Potentials of field beans and other food legumes in Latin America

Material Information

Potentials of field beans and other food legumes in Latin America February 26-March 1, 1973 edited by Duncan Wall
Series Title:
Series seminars no. 2E
Wall, Duncan
Centro Internacional de Agricultura Tropical
Seminar on Potentials of Field Beans and other Food Legumes in Latin America, 1973
Place of Publication:
Cali Colombia
Centro Internacional de Agricultura Tropical
Publication Date:
Physical Description:
x, 388 p. : ill. ; 24 cm.


Subjects / Keywords:
Legumes -- Congresses ( lcsh )
Food supply -- Congresses -- Latin America ( lcsh )
Beans ( jstor )
Food ( jstor )
Crops ( jstor )
bibliography ( marcgt )
non-fiction ( marcgt )
conference publication ( marcgt )


Includes bibliographies.

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Full Text

Paper prsete in SEIARo

Cali C o i Februar 26- M c 1, 1

Cetr Unencoa cl Agiutr Tr~*6S opica


Potentials of field beans

and other
food legumes

Latin America

February 26- March 1,1973

Centro Internacional de Agricultura Tropical
Call, Colombia

The articles contained in this publication were edited by
Mr. Duncan Wall, Tacoma Park, Maryland, U. S. A. His
valuable contribution to CIAT's effort in publishing the
proceedings of the Bean Seminar is highly appreciated.

ACKNOWLEDGEMENT: Research and training activities reported for
the calendar year 1973 were financed by grants from a number of do-
nors, principally the United States Agency for International Develop-
ment, the Ford Foundation, the Rockefeller Foundation, the Canadian
International Development Agency, the W.K. Kellogg Foundation, and
the Government of the Netherlands. In addition. special project funds
were supplied by the International Development Research Centre of
Canada and the Interamerican Development Bank. Information and
conclusions reported herein do not necessarily reflect the position of
any of the agencies, foundations, or governments involved.

This publication was produced by the
office of Information Services (Training
and Communications Program of CIAT).
Our address: Apartado Aereo 67 13.
Cali, Colombia, S. A.



Summary Report of the Seminar VI
List of Speakers Ix
List of Discussants N
Moderators X

Section I

Food Legumes and Human Protein Needs 1

The improvement of food legumes as a contribution to improved human
nutrition. Samuel C. Litzenberger. 3

Acceptability and value of food legumes in the human diet. Ricardo
Bressani. 17

J. E. Dutra de Oliveira and Nelson de Souza 49

Problems and potentials in storage and processing of food legumes in
Latin America. Luis G. Elias. 52

Factors and tactics influencing consumer food habits and patterns.
Marina Flores. 88

Francis C. Byrnes 115

Section 2

Production of Food Legumes 121

Relative agronomic merits of various food legpmes for the lowland
tropics. Ken O. Rachie. 123

H. Doggett 140
A. M. Pinchinat 142

Potentials and problems of production of dry beans in the lowland
tropics. Guillermo Hernandez-Bravo. 144
Luis H. Camacho 151
Colin Leakey 157

Bean production systems. Juan Antonio Aguirre and Heleodoro Miranda. 161

Fernando Fernandez and David L. Franklin 188

Agronomic practices for food legume production in Latin America.
George F. Freytag. 199

Goals and means for protecting Phaseolus vulgaris in the tropics.
W. J. Zaumeyer. 218

Leonce Bonnefil 229
Rodrigo Gamez 233

Section 3

Plant Type and Bean Breeding 237

Plant introduction and germplasm of Phaseolus vulgaris and other food
legumes. Clibas Vieira. 239

Efraim Hernandez X. 253
Harold F. Winters 259
Colin Leakey 263

Plant architecture and phisiological efficiency in the field bean.
M. W. Adams. 266

A. M. Evans 279
D. H. Wallace 287
H. C. Wien 296

Section 4

Implementing Institutional Cooperation 299

Organizational and institutional opportunities for food legume programs in
Latin America. A. Colin McClung. 301

Report on survey of the food legume situation in Latin America.
Antonio M. Pinchinat. 311

Modern approaches to training of food legume scientists in the tropics.
Fernando Fernandez. 324

The design of an information network as a support to scientific research.
Fernando Monge. 339

Appendices 349

I. Report of Moderators 351
II. Reports of Disciplinary Work Groups 352
III. Reports of General Work Groups 361
IV. Summary of the answers to the post-seminar evaluation
questionnaire 375
V. List of participants 382


It was in Latin America that man first brought the common bean in from the
wild and added it to the world's great food crops. In the ancient cultural patterns of
Latin America's people, it is fiatural that beans hold a special place in traditional
agriculture and accustomed foods.

Along with their edible relatives in.the legume family, beans both offer
promise, and pose stubborn problems, for hungry millions everywhere. This is
nowhere more evident than in the developing countries of Latin America.

What is the promise? Into diets too narrowly based on cereals such as maize,
or roots such as cassava, beans and other food legumes bring quantities and qualities
of body-building protein lacking in the customary daily food of lower income people.
Protein is vital need, particularly of the growing young. No source of the needed
protein, other than food legumes, is so close to the means of, and so accepted by, the
masses of people.

What are the problems? Climatic hazards and prevailing low-level technology
keep bean yields low. Demands exceed supply and keep market prices beyond reach
of many low-income people, even while farmers too commonly find growing bean
risky and commercially unprofitable. The subsistence farming family simply hopes,
too often vainly, that the little bean plot will fend off hunger. Even if we learn how to
produce more beans, there are gaps in our knowledge of how best to process beans
into various food products, and how best to utilize their food values.

What are the solutions? They are not simple. Both technological and socio-
economic actions are needed. While the long-term problems are tackled, short-term
ingenuity is needed. Plant breeders can raise yields by combining productive genes
from the wide variety found in the many strains of Phaseolus vulgaris (the common
field bean).

Agronomists, with the help of entomologists and pathologists, can devise better
ways of planting, tending and protecting the crop. More effective storage methods
can be developed along with ways of processing beans into new and perhaps more
acceptable foods. Aided by newly built-in qualities, nutritionists can explore how to
use beans in healthful, satisfying diets compatible with traditional customs.
Extension workers can carry the new "technology package" to farmers and new
dietary knowledge to homemakers. Governments can provide the infrastructure of
supporting institutions.

To confront this complex of promise-problems-solutions, a Seminar on The
Potentials for Field Beans and Other Food Legumes in Latin America and the
Caribbean was organized by CIAT-Centro Internacional de Agricultura Tropical. The
seminar took place February 26-March 1, 1973, in Cali, Colombia, CIAT's base.

From more than 20 countries on'five continents, from national and international,
public and private, institutions, some 150 participants came to hear 32 speakers-not
only to listen, but also to contribute their own experience and insights in lively
inter-disciplinary discussions. They were scientists in a dozen biological and social
disciplines; researchers and practical agronomists and engineers; administrators and

One result, is the gathering together of a great fund of knowledge about the
potentials and the problems of food legumes. This information is being published by
CIAT in English and Spanish for widespread circulation.

Out of the Seminar came no new Institute or "Program," nor was this intended.
The national and international organizations represented are already, each in its own
way, engaged in programs spanning research, training, communication, and action
in the field.

There resulted, however, agreement to find practical means to link all these
efforts together and so to focus more sharply upon recognized priority tasks.

To this end, the seminar participants asked the Seminar Steering Committe
to form a small task force to draft a proposal as to how these linkages might be most
effectively forged. This request came at the conclusion of a plenary session in which
the reports of 12 general discussion groups were heard and consolidated.

While there was unanimous agreement abouf the convenience and desirability
of establishing a regional cooperative network or program, suggestions varied with
respect to criteria of formulation and operation. It general, it was considered
convenient to review the experiences obtained in Latin American institutions such as
the Central American Cooperative Program for Food Crops Improvement (PCCMCA)
that could be the basis for the establishment of a wide-ranging network.

Participants agreed that an international network must not replace national
activities, but must complement and provide effective liaison among them. Activities
suggested for consideration included cooperative research projects, publication and
documentation systems, conferences and symposia, exchange of personnel, training,
and operation of germplasm banks.

Once operating, the network could also help channel research activities and
technical and financial resources to member institutions.

Within one hour after adjournment of the seminar, the Steering Committee
met and nominated three persons to staff the proposed task force. All had
participated in the seminar and were still available. When invited to serve on the
Task Force, all three agreed to do so.

Members of this group are Dr. Ricardo Bressani, Institute for Nutrition in
Central America and Panama, Guatemala City, Guatemala; Dr. Luis Marcano,
president, Shell Foundation, Caracas, Venezuela, and Dr. Oswaldo Voysest,
Departamento de Leguminosas de Grano, Estaci6n Experimental "La Molina,"
Lima, Peru.

In addition to the papers of the seminar and the specific comments which the
participants were invited to send the Task Force, the group will draw upon the
recommendations of the 12 discussion groups mentioned above as well as the reports
of the six disciplinary work groups. These latter reports identify the major problem

areas, assign priorities to the problems, propose approaches to consider and suggest
the institutions and individuals which the people from that discipline attending the
seminar believed might most appropriately undertake the needed work.

Specific research-oriented goals of a coordinated program were outlined as
follows: To idelitify research areas of common interest; to establish priorities among
these; to plan experimental work toward these objectives; to seek additional funds
when needed to carry out the indicated experiments; to assist various cooperators to
conduct the agreed upon research, and to evaluate and disseminate the results of the
cooperative research effort.

While each disciplinary work group listed several areas for priority attention,
some of the areas emphasized by each group were as follows:

Agronomy: Greater attention to the cultural practices of small bean producers
in hilly areas who grow beans inter-planted with other crops, as well as varieties and
practices for tho, who produce beans as a monoculture, commercial crop.

Breeding: Increased efforts to identify and to incorporate into productive
genotypes resistance to a wide spectrum of insects and disease.

Plant Physiology: Intensive research on the physiological capabilities that
limit yield in a continuing program to determine superior plant types.

Crop Protection: Location of sources of resistance for or means of controlling
the-principal diseases (rust, root rot, bacterial blight, common mosaic, golden mosaic)
and the main insect pests (small harvest flies, lady bugs, cutworms, aphids, storage

Economics and Nutrition: Establish nutritional and chemical composition
patterns according to eating habits; study price stabilization mechanisms attractive
to producers and consumers; seek improved means of taking technology to farmers;
study bean processing; establish adequate storage conditions, and provide more
reliable statistical information on production and prices.

Administration: Form a small task force to develop plans and criteria for an
international network for bean improvement.

(in order of presentation)

Samuel C. Litzenberger
Agronomy Research Specialist
Office of Agriculture
Technical Assistance Bureau
U. S. Agency for International Development
Washington, D. C., U. S. A.

Ricardo Bressani
Head, Division of Agricultural and Food Sciences
Institute de Nutrici6n de Centro America y PanamB
Apartado Postal 1188
Guatemala City, Guatemala, C. A.

Luis G. Elias
Scientist, Division of Agricultural and Food Sciences
Institute de Nutrici6n de Centro America y Panama
Apartado Postal 1188
Guatemala City, Guatemala, C. A.

Marina Flores
Head, Division of Applied Nutrition
Institute de Nutrici6n de Centro America y Panama
Apartado Postal 1188
Guatemala City, Guatemala, C. A.

Ken O. Rachie
Leader, Grain Legume Improvement Program
International Institute of Tropical Agriculture
Oyo Road, P. M. B. 5320
Ibadan, Nigeria

Guillermo Hernandez-Bravo
Bean Program
Cali, Colombia

Juan Antonio Aguirre
Agricultural Programmer
Northern Zone
Interamerican Institute of Agricultural Sciences
Apartado 1815
Guatemala City, Guatemala, C. A.

Heleodoro Miranda
Agricultural Researcher
Northern Zone
Interamerican Institute of Agricultural Sciences

Apartado 1688, Sucursal 1
San Salvador, El Salvador, C. A.

George F. Freytag
Chief of Party and Professor of Plant Breeding
University of Wisconsin Contract US/AID
Universidade Federal do Rio Grande do Sul
Caixa Postal 09676
Porto Alegre, R. S., Brazil

W. J. Zaumeyer
U. S. Department of Agriculture
Washington, D. C., U. S. A.

Clibas Vieira
SProfessor of Agronomy
Federal University of Minas Gerais
Vicosa, M. G., Brazil, and
National Bean Project
Ministry of Agriculture
Brasilia, Brazil

M. W. Adams
Department of Crops and Soil Science
304 Agriculture Hall
East Lausing, Michigan. 48823. U. S. A.

A. Colin McClung
Deputy Director General
Cali, Colombia

Antonio M. Pinchinat
Centro Tropical de Ensefianza e Investigaci6n
Interamerican Institute of Agricultural Sciences
Apartado. 74
Turrialba, Costa Rica,,A. C.

Fernando Fernandez
Plant Science Training Program
Cali, Colombia

Fernando Monge
Associate Communication Scientist; Librarian
Cali, Colombia

(In order of presentation)

J. E. Dutra de Oliveira
Medical School
Ribeirao Preto, Sao Paulo, Brazil

Nelson de Souza
Medical School
Botucatu, Sao Paulo, Brazil

Francis C. Byrnes
Training and Communication
Cali, Colombia

H. Doggett
International Development Research Centre
Ottawa, Canada

Antonio M. Pinchinat
(see List of Speakers)

Luis H. Camacho
Food Legumes Program
Institute Colombiano Agropecuario (ICA)
Bogota, Colombia

Colin Leakey
Makarere University
Kampala, Uganda

Fernando Fernandez
(see List of Speakers)

David L. Franklin
Systems Engineer
Harvard University
Cambridge, Massachusetts, U. S. A.

Leonce Bonnefil
Department of Natural Resources
Puerto Rico

Rodrigo Gamez
Faculty of Agronomy
University of Costa Rica
Ciudad Univorsitaria "Rodrigo Facio"
San Jose, Costa Rica

Efraim Hernandez X.
Research Professor
Colegio de Postgraduados
Escuela Nacional de Agricultura
Chapingo, Estado de Mexico, Mexico.

Harold F. Winters
Plant Genetics and Germp!asm Institute
Germplasm Resources Laboratory
U. S. Department of Agriculture
Washington, D. C., U. S. A.

Colin Leakey
(see above)

A. M. Evans
Department of Applied Biology
University of Cambridge
Cambridge, England

D. H. Wallace
Plant Breeding and Biometry Department
Cornell University
Ithaca, New York, U. S. A.

H. C. Wien
International Institute of Tropical Agriculture
Ibadan, Nigeria.


Leobardo Jimenez S.
Colegio de Post-Graduados
Escuela Nacional de Agricultura, E. N. A.
Chapingo, Estado de Mexico

Alberto Pradilla
Unidad Metabolica
Departamento de Pediatria
Universidad del Valle
Call, Colombia.

Section 1.


The improvement of food legumes as a contribution to improved human nutrition

Samuel C. Litzenberger

Acceptability and value of food legumes in the human diet
Ricardo Brcssani

Discussants: J. E. Dutra de Oliveira and Nelson de Souza

Problems and potentials in storage and processing of food Jegumes in Latin

Luis G. Elias

Factors and tactics influencing consumer food habits and patterns
Marina Flores

Discussant: Francis C. Byrnes


Samuel C. Litzenberger

The FAO Food Survey estimates that on a world basis some 10 to 15 percent of
the people are undernourished and up to half suffer from hunger or malnutrition
or both. These nutritional deficiencies are most serious within the developing
countries. According to Schertz (7) about two-thirds of the world, the poor countries,
consume only half of the world's protein; and this is mostly cereal protein. If the
projected population increases are realistic, that within the next generation the
world's population will double, the food situation will worsen unless substantial
effort is directed toward increasing food production.

Undernourishment or malnutrition may arise from inadequate caloric intake,
protein deficiencies, and a shortage of vitamins and minerals. Of these deficiencies
protein deficiency has aroused the greatest concern. Protein hunger may largely be
overcome by an increase in availability in animal or plant proteins at price levels the
affected population can afford, or through fortification. These alternative routes
have often been considered as competitive; in reality they are complementary. Each
alternative has special advantages and disadvantages and both have their inherent

In fortification the costs include the price of the basic ingredients (soybean flour,
fish concentrate, amino acids, minerals, vitamins, etc.) and the costs of transportation,
dietary incorporation and distribution. The costs of materials can be calculated but
the characteristics of the target population ( age profile, geographic
distribution, etc.) are largely unknown making transportation and distribution costs
difficult to estimate.

Increased plant or animal proteins can be achieved from improved plant varieties
and from better management practices. These, in turn, require increased expenditures
for research. Increased levels of productivity resulting from research can be predicted
almost with certainty but the costs involved are less predictable. This is true because
for many crops the potential for improvement is largely unknown. Secondly, the
efficient utilization of improved cultivars is somewhat dependent upon the local
infrastructure (extension effort, seed production and distribution facilities,
transportation and marketing facilities, etc.). Thus, any precise cost comparisons
between the alleviation of protein deficiency through breeding, or through
fortification are not possible at present.

Table 1. Comparative cost of major protein sources in human diets

Food Source US$/kilo /o Protein US$/kilo protein

Beef 1.54 15.2 10.12
Pork 1.10 11.6 9.46
Poultry 0.66 20.0 3.30
Nonfat dry milk
solids 0.32 35.6 0.90
Dry beans 0.18 23.1 0.77
Soybeans 0.11 34.9 0.31
Oats 0.051 13.0 0.40
Wheat 0.062 12.2 0.51
Maize 0.057 9.5 0.59
Potatoes 0.11 2.0 5.50

Source: Dimler, R. J. Soybean protein food. Soybean Protein Foods 1966, Agr. Res. Service,
USDA 71 35 May 1967.

This paper will be concerned only with the possible role of the food legumes in
alleviating protein deficiency and opportunities for increased production. As for
comparative costs of major protein sources in human diets, the cost per kilo of
protein for crops is strikingly lower than that for animal protein (Table 1). Of those
listed, cereals and soybeans are the least costly.

The world over, vegetable proteins account for approximately 70 percent of the
protein in the human diet and animal proteins some 30 percent. In the developing
countries even less of the total dietary protein comes from animal sources. Cereal
proteins make up more than 70 percent, a sizeable fraction of the total vegetable
protein consumed. The protein content of cereals normally ranges from about 8 to
16 percent. In each of the cereals, protein quality is below the optimum need of
man; some one or more of the essential amino acids being limiting, the major ones
being lysine and tryptophan. Small animal trials run on opaque-2 maize, high proly,
barley, high protein wheats, and on the man-made species triticale, indicate that
even within the cereals, improvements in protein quantity and quality are being

Compared with the cereals and root/tuber crops the food legumes in general
present a much more favorable picture with respect to both quantity and quality of
protein. Protein varies from 20 to 40 percent. Methionine and to some extent cystine,
both sulfur-bearing, are usually the most limiting amino acids. Thus cereals and
legumes complement each other very satisfactorily, both in terms of protein content
and quality. The food legumes, when raw, contain a number of toxic factors. Most
of these, however, are destroyed by normal cooking procedures. The heat stable
factors which must be considered include cyanogens, alkaloids (most serious in
Lupinus species), lathyrogens (Lathyrus sativus), favism (Vicia faba) and flatulence

Approximately 20 species of the Leguminosae family are used for human food in
some area of the world. Eight of these are most extensively grown but even within
this group there are striking differences in area of adaptation and use. Roberts (5)
has grouped six of these into four major classes depending primarily upon climate
requirements. These are as follows:

A. Low humid tropics
(1). Pigeon peas (Cajanus cajan)
(2). Cowpeas (Vigna sinensis)

B. Semidry or seasonal tropics
(3). Groundnuts or peanuts (Arachis hypogaea)

C. Tropical intermediate elevations to temperate zones
(4). Soybeans (Glycine max)
(5). Dry beans (Phaseolus vulgaris)

D. Cool weather, high elevation zone
(6). Chickpeas (Cicer arietinum)
(7). Peas (Pisum sativum)
(8). Broad beans (Vicia faba)

We have added peas and broad beans to the Roberts' list with chickpeas in the
cool weather group because of their relative importance as food legumes in these
special environments. Next to soybeans and groundnuts, peas and dry beans are the
most extensively grown legume crops, each occupying about 10 percent of the
world's area planted to food legumes. After these in importance come the broad
beans, averaging about 5 percent of the area planted.

The limitation of food legumes to the above eight species must be somewhat
arbitrary. In certain geographical areas other species would equal or exceed them
in importance. For example, lentils and broad beans are grown as extensively as
chickpeas in the Near East and pigeon peas, although widely grown, are of little
importance as a food crop in Africa. Similarly cowpeas are yet only of major
consequence in Africa as a legume food crop.

Data on production and on average yield by regions, for a selected group of
legumes and oilseed species, are presented in Table 2. Average yields for any given
species vary greatly among regions and only soybeans and peas on a worldwide basis
and to a lesser extent groundnuts and broad beans exhibit any marked yield
superiority. These average yields, however, provide a poor measure of yields which
might be expected under more favorable management practices.


If the six species listed by Roberts (5) plus certain others of regional importance,
are to play an important role in alleviating protein deficiency a greatly expanded
research program will be required. With a few notable exceptions, only limited
research has been done on food legumes encompassing a balanced program involving
both the development of improved cultivars and a careful examination of soil
management and production practices. In terms of grain yield per hectare the food
legumes are characteristically lower yielding than the cereals. Critical data are lacking
to establish what fraction of the yield differential is inherent and what fraction a
reflection of the limited research effort expended.

Table 2. Average world and region production of grain in thousands ot metric tons (M /MT) and yield in hundreds of
kilos for a selected group of legumes and oil seed species

World Total North America Latin America -Near East Far East Africa
Crop Production/Yield Production/Yield Production/Yield Production/ Yield Production/ Yield Producton/ Yield
(M/MT)/(kg/ha) (M/MT)/(kg/ha) (M/MT)/(kg/ha) (MAIT) /(kg/ha) (M/MT) /(kg/ha) (M/MT) /(kg/ha)

10708(11) 1_ 4.7 833 15.3 40032- 5.9
10115(10) 11.5 197 16.3 101 6.9
4636( 5) 9.9 189 5.9
7445( 7) 6.9 150 7.2
996( 1) 6.2 31 12.4 22 5.9
1829( 2) 6.3 31 7.0
1083( 1) 3.9 25 6.3 -

43613(44) 13.0 30269 18.1 903 10.5

15034(15) 8.5 1153 19.8 1246 11.5
16285 2.9 4 4.0 3211 6.6
9944 12.7 102 9.5 1032 8.7

195 11.0 2619 3.1 805 6.0
7 17.5 970 9.2 352 7.3
328 15.0 11 12.2 341 8.3
206 9.1 6558 6.9 316 6.3
223 7.7 458 5.1 128 5.9
1760 6.4 38 3.8
16 12.3 26 6.2 1004 3.7

9 11.3 1161 7.0 23 7.7

292 7.8 5869
2107 3.6 5930
237 9.6 -

7.0 4219 8.1
1.9 1305 3.0
- 155 6.0

Source: 1969 FAO Production Yearbook Vol. 23.
1/ Numbers in parentheses indicate percentages of world total food legume production which totaled 101,347,000 metric tons.

2/ Values darkened indicate the current world center of production of the crop listed. For dry peas and sunflowers it is Russia with respective production of 4,818,000 and
6,685,000 M.T., and for yield of 1,540 and 1,370 kg/ha. For broad beans it is Mainland China with an average production of about 3,000,000 MT and a yield of 980 kg/ha.

Pulse Crops
Dry beans
Dry peas
Broad beans
Pigeon peas

Oil Seed Crops
(in shell)

For the production of protein nutrition per hectare not all of the food legumes
yield less protein nutrition per hectare than the cereals (Table 3). Soybeans averaged
about 150 percent more than the three most extensively grown cereals in the world;
groundnuts were nearly 25 percent more productive, while peas were nearly 10
percent higher. For dry beans, one of the most extensively grown food legumes in
Latin America, protein nutrition averaged about 30 percent less than the best of the
cereals. The other food legumes yielded progressively less.

While climate is a major limiting factor in the ultimate yield of any crop, it is
apparent from these data that past concerted effort in breeding and selection has
undoubtedly played a major role in giving comparative advantages to soybeans, peas
and groundnuts for yield superiority. For example, starting from a tropically-adapted
plant the soybean was transformed through a concerted effort into one of the most
efficient producers of grain of any of the legume crops in the temperate zone. This
is not to indicate that no further improvement is possible. Quite the contrary, since
the past efforts were geared mostly toward the production of a seed with the highest
content of oil.

Continued orientation of research to the development of types with more and
better protein and the selection of plant types particularly well adapted to the
tropical and subtropical environments can develop equally superior plants not only
for the soybean, but can be similarly effective in improving yields of other selected
food legumes. Most species are endowed with sufficient genetic diversity to make
this advancement possible, otherwise they would already have disappeared as species.
Continued effort on the part of research is necessary, first to locate the needed
genetic factors and then to combine them into the winning combination.

Fields in which additional research is obviously needed include the development
of higher yielding cultivars having the maximum possible resistance to disease and
insect pests of local importance; improvements in protein percentage, amino acid
balance and other nutritional qualities; and the development of better soil management
and production practices.


In tropical areas work on varietal improvement of food legumes has suffered from
lack of continuity as well as limited resources. Where major advances have been
realized, e.g., beans in Mexico and Colombia, cowpeas in Nigeria, pigeon peas in
India, etc., the new varieties have had only limited impact due to restricted seed
production and distribution programs and extension efforts.

At the Stockholm Conference on Human Environment considerable emphasis was
given to the necessity for the collection and preservation of both cultivated and wild
plant species. The importance of such efforts cannot be over-emphasized. One of the
first requirements for effective breeding research with any crop is an adequate
germ plasm reservoir of the variability characterizing the species. Some collections
exist hut it is questionable if these are adequate for any of the species of interest.

Major collections now available include beans, soybeans and peanuts maintained
by the U.S. Department of Agriculture, beans by CIAT, cowpeas by IITA and the
Nigerian Government. A program in Iran and India supported by AID and the
Agricultural Research Service (ARS), U.S. Department of Agriculture, assembled a
collection of some 26,000 items representing 10 species. This collection is currently

Table 3. Relative efficiency of worldwide protein production of selected food crops

Protein World avg
Total Protein content yield
Crop world Grain content Nutritional nutritional protein
production yields of seed value coefficient nutrition

(Million MT) (MT/ha)

Legume food crops
Dry beans
Dry peas
Broad beans
Pigeon peas

Cereal grain crops

Rice (Paddy)

Potatoes (Irish)



% egg protein)





Sources: 1969 Production Yearbook (FAO Vol. 23) and 1970 Amino Acid Content of Foods and Biological Data on Protein
(FAO Vol. 24).

being maintained by the All India Coordinated Pulse Program and by the U..S.
Department of Agriculture in Puerto Rico. In addition, smaller collections involving
items of local interest are maintained by each active breeding program.

The assembling of germ plasm variation in world collections, however large, is of
limited value unless adequate provision is made for both maintenance and evaluation.
Too often, these two activities have been dependent upon the interests of a very few
individuals. As a result, neither effort has'been completely satisfactory.

Roberts (5) has suggested a system which should give a greater degree of stability
and usefulness to collections now in existence and for their further expansion. This
responsibility would be assumed by the several International Institutes. Some of his
recommendations have already become a reality. For example, dry beans are currently
being supported to a beginning extent by CIAT; cowpeas have been accepted by
IITA as a major pulse crop for needed research and training on an international basis;
pigeon peas and chickpeas are now the international responsibility of ICRISAT;
soybeans were to have been assigned to CIAT or IITA and groundnuts possibly to

No priority support was indicated for dry peas or broad beans, two of the food
legumes which have shown some real advantages as producers of quality protein in
volume in selected environments. The Federal Station at.Mayaguez and the University
of Puerto Rico would continue their general interest-in soybeans for the tropics and
subtropics in cooperation with the University of Illinois and its large legume collection.

As for the mungbean, while the brief production and seed quality data of Table
3 show it to be a poor performer, its importance as a short-seasoned catch crop
following other regular crops, especially rice, in tropical regions requires some
research support: This will probably be forthcoming from the Asian Vegetable
Research Development Center (AVRDC), Taiwan,which will be working very closely
with IRRI.

Regardless of the final disposition of responsibilities for further collection and for
maintenance, provision must also be made for a network of cooperating stations to
accumulate the information needed on relative yield performance, day-length
responses and disease and insect reactions.

More recently AID has been encouraged by the Consultative Group (CG) through
TAC (Technical Advisory Committee on International Agricultural Research) to
consider the development of an International Soybean Resource Base at the
University of Illinois where advantage would be taken of the vast competence that
already exists with this crop in the U. S. at the University and as supported by the
Regional Soybean Laboratory located nearby. To support its immediate need for a
U. S. based tropical environment Puerto Rico would become an integral part of the
Resource Base.

Such a proposal would serve as the nucleus for the ultimate establishment of
an international institute providing research and training services to the international
soybean network much as is currently being done by the other international crops
centers. Outreach and linkage activities would be handled comparably to those
already worked out for the different crops by the international institutes. Soybean
Resource Base activity linkages with IITA, CIAT, ICRISAT, IRRI, etc., would be
envisioned to be direct and supported by multilateral funding through the CG.

In the Regional AID/ARS Pulse Improvement Project which has variously
cooperated with India, Iran, and at Puerto Rico, since 1969 for special support to
Latin America on bean and cowpea diseases and related insects, tremendous
differences have been observed among the collections representing each species.
These variations included apparent yield potential, maturity, plant type and
resistance to various diseases and insect pests. It was apparent that major
improvements could be achieved by selection among and within currently grown
types. Even greater increases in yield potential should be possible by selection among
the progeny of carefully selected parents or through population breeding where a
broad genetic base is required to control limiting diseases and insects. Relatively little
breeding work of this type has been undertaken and yet this is the simplest way in
which desired recombinants may be produced.

Each crop poses its own peculiar problems. Extensive breeding work has been
done on soybeans within the temperate regions and a large number of commercial
varieties are available. Soybeans, however, are day-length sensitive and these varieties
are of limited usefulness outside the region of their development. Most of these
varieties would be poorly suited to the range of day-lengths prevailing in the tropics.
Many other legumes exhibit similar response to variation in day-length. Similar, the
major disease and insect pests vary from species to species and, possibly to a lesser
extent, with ecological zones. It is thus apparent that any screening or selecting of
improved types must be done in the environment in which the crop is to be
ultimately grown.

Breeding and management are complementary activities; high yielding cultivars
cannot express their potential if water or fertility is limiting. Similarly, good
management cannot compensate for inferior germ plasm. This relationship requires
that breeding and management studies be conducted simultaneously. Population
densities, time of planting, pest control, water distribution and fertility regimes each
may affect yield response and must therefore be incorporated into any breeding and
evaluation program. Knowledge of response under an adequate or optimum regime is
required to provide useful information on relative yield potential.


Information on variation in protein percentage is available for several of the food
legumes. Environmental effects are known to be important. Corresponding information
on the effects of environment on the individual amino acids is much less extensive.

Protein content

The most extensive work on protein variation has been done in soybeans (1).
Protein and yield are negatively correlated as are also protein and oil content. These
correlations, while statistically significant, are not so great as to be a major barrier to
genetic progress. The major emphasis in modifying composition has been directed
toward increasing oil percentage. Only limited effort has been directed toward
increasing protein percentage yet two varieties, Protana and Bonus, have been
released having approximately 43 percent protein. If protein were to receive increased
emphasis it appears that still higher types could be developed.

Silbernagel (8) has screened a large number of bean varieties and; introductions
and found protein values ranging from 16 to 33 percent. Protein percentage was found
to be influenced by environment with considerable variation among both locations
and years. Certain lines, however, were consistently high in protein under all
environments tested. Rutger (6), also working with beans, found variation in protein
content ranging from 19 to 31 with a mean of 24.6 percent. Within the sample of
lines used yield and protein content were not significantly correlated but a positive
correlation was observed between protein content and late maturity and negative
correlation between protein and seed weight.

While mungbeans were not included in the select group of six listed earlier, variation
in protein percentage is of some interest. Studies were conducted at the University
of Missouri in 1970 and 1971 AID contract. Among the 313 strains tested
from the world collection protein percentage ranged from 19.1 to 28.3 percent in
1970 and from 22.1 to 31.2 percent in 1971. Yield, protein percentage and seed
weight were negatively correlated.

In studies conducted in India with chickpeas, pigeon peas, mungbeans, peas and
cowpeas, Krober et al (3) reported significant varietal differences in protein content.
No significant differences were found among the urd bean and lentil varieties tested.

From the rather limited data available, it appears that protein content is under
some degree of genetic control; however, the pattern of inheritance has not yet been
established. The development of higher protein types should therefore be possible in
most of the species examined. An effect of environment on protein content was noted
in most studies. This relation complicates the problem of breeding for increased
values as the material must be evaluated under a range of environments to obtain a
fair measure of real differences. The extent to which environmentally induced
differences can be minimized by uniform management practices remains to be

Protein quality

Information on amino acid profile in the food legumes is less detailed than for
protein content. Data for some of the legumes of interest are presented in Table 4.
Some cereal and root/tuber crops and animal products are included for comparison.

Two points are of particular interest. First, lysine values tend to be high for the
legumes. This fact is responsible for the complementarity of cereals and legumes.
Second, there are rather large variations in the methionine plus cystine values among
the different leguminous species. The values given serve for average comparative
purposes but have the limitation that the samples tested were not necessarily grown
under uniform conditions.

In breeding for improved protein quality primary emphasis must be given to
methionine, as it is normally the first limiting amino acid. Cystine variation would
also be of some interest as methionine and cystine exhibit a mutually sparing relation.
Possibly some attention should also be given to lysine to ensure discarding strains
with below normal values.

The ion exchange amino acid analyzer is not well suited to the needs of the plant
breeder who is concerned with the evaluation of large numbers of samples. The
microbial assay, though possibly less precise, can be more readily adapted to handle

Table 4. Comparison of amino acid content per 100 grams of food

Sulfur-containing amino acid
Total Total
Food Moisture Protein Lysine Methi- Cystine Total Trypto- essential amino
(grams) (grams) (mg) onine (mg) phan amino acids acids
(mg) (mg) (mg) (mg)

Cereal Grains
Maize 12 9.5 254 182 147 329 67 3,820 9,262
Rice-brown 13 7.5 299 183 84' 264 98 3,033 7,973
-polished 13 6.7 255 150 108 259 95 2,695 6,785
Wheat 12 12.2 374 196 332 528 142 4,280 12,607

Roots and Tubers
Potato 78 2.0 96 26 12 38 33 667 1,572
N Yam (Dioscoria) 72.4 2.4 97 38 27 65 30 821 2,009
Cassava (Manihot) meal 13.1 1.6 67 22 23 45 19 404 1,184

Legumes (pulses)
Beans (Phaseolus) 11 22.1 1,593 234 188 422 223 8,457 20,043
Beans, Broad (Vicia) 11 23.4 1,513 172 187 359 202 8,244 20,951
Chickpea 11 20.1 1,376 209 238 447 174 7,802 19,290
Cowpeas (Vigna) 11 23.4 1,599 273. 255 528 254 8,640 21,086
Peanut 5.2 25.6 1,036 338 366 704 305 9,502 27,610
Lentil 11 24.2 1,739 194 221 415 231 9,504 23,447
Lima bean 11 20.0 1,466 246 199 444 199 8,359 19,104
Muhgbean 11 23.9 1,927 126 168 294 8,547 20,344
Peas 11 22.5 1,692 205 252 457 202 8,464 20,901
Pigeon pea 11 20.9 1,607 107 204 311 117 7,505 18,460
Soybean 8 38.0 2,653 525 552 1,077 532 16,339 40,945

Meat and Poultry
Beef and Veal 61 17.7 1,573 478 226 704 198 7,875 17,163
'Chicken 66 20.0 1,570 502 262 764 205 8,380 18,206
Egg (Hen) 74 12.4 863 416 301 717 184 6,338 12,763
Fish meal 10.1 75.0 5,808 2,052 924 2,976 720 30,360 70,308

large numbers. The modified microbiological assay developed by Kelley cE al (2) has
been used extensively on beans. From a study involving 3,600 strains he concluded
that methionine level was under genetic control and speculated that through
breeding and selection the present level of critical amino acids might be doubled.
Work with mungbeans at Missouri (9, 10) indicated a three-fold range in methionine
content. Unfortunately, here appeared to be an inverse relation between protein
and methionine content.

Amino acid compositional studies are under way at a number of institutions in
both the U.S. and India. Hopefully, information will soon be forthcoming on the
inheritance patterns of the individual amino acids of interest and their interactions
with both protein and environment established.

Other nutritional characters

The heat stable factors of greatest concern include the cyanogens, alkaloids,
favism and flatulence factors. Fortunately, all of these factors are not common to
all species and therefore routine screening of all material may not be necessary. Any
new variety, however, should be carefully evaluated for all heat stable factors before
release. Assay procedures are available for the factors of greatest potential importance.

Wide variations in the time required for cooking exist among the food legume
species. Reduced cooking time may be an important factor in consumer acceptance
of new cultivars where fuel is in limited supply.
Evaluation of each of the factors of interest (amino acid composition, heat stable
factors and cooking time) can be incorporated into a laboratory screening program
closely coordinated with a breeding program. Staff and funds required for such an
effort will, however, be substantial. Experience will likely dictate that some
priorities be established and that only a small segment of the breeding material will
be subjected to all tests.

The final evaluation of any breeding product must depend upon nutrition studies
with appropriate test animals, both when utilized as the major source of protein and
when utilized in combination with normally available cereal and root and tuber crops
that are consumed with it. Differences in amino acid nutritional availability have
been demonstrated in some of the cereals and may exist more widely even in the food
legumes. Unfortunately, because of the quantities of material required, nutritional
evaluation must be deferred until late in the breeding and evaluation process.
However, this is an early must for any new variety being considered for release. For
obvious reasons this should even be a basis for selecting parent stocks in any expanded
breeding program.


The complementary relation between breeding and management has already been
mentioned. Management studies on the food legumes have been limited. A partial
explanation for this arises from the wide differences in cultural practices employed.
Legumes may be grown in nionoculture or as mixtures with corn, sorghum, cotton
or other crops. When grown in mixtures, the regime of planting time and fertility is
that employed for the major crop. This may or may not be optimum for the legume.

When grown in monoculture it has commonly been assumed that nitrogen
requirements will be satisfied through nitrogen fixation by appropriate strains of
Rhizobium. In studies with soybeans in Illinois the use of nitrogen fertilizer has
given some increase in yield but the level of response was not economic. Nitrogen
applications, however, did produce a higher protein percentage in the seed. The
need for phosphorus and potash will be dependent upon soil characteristics
and previous management and cropping practices. With the introduction of any
relatively new species into a community either for testing or production, and
especially in the tropics and sub-tropics, assurance of appropriate nitrogen fixation
by Rhizobium is of prime importance.

Plant population must be geared to rainfall distribution patterns and stored soil
moisture unless water needs are to be met through irrigation. Fertilization levels
must be geared to both available water and population levels.


Unless plant breeding and management research are successful in increasing
average yield levels to the extent that they become competitive with cereals, the
deserved increase in production may be difficult to achieve. Some data from India
(Table 5) may serve to illustrate the problem.

Prior to the introduction of the short-statured wheats, yields of wheat were
approximately 30 percent greater than for chickpeas (gram). With approximately
equal prices, returns per unit area would correspond to the average yields. With the
current extensive use of the new improved wheats and the accompanying
improvements in management practices yields per hectare have nearly doubled while
yields of chickpeas have shown little change. The effect of this example is.self

Thus, in 1970, per unit area returns from wheat were nearly double those from
chickpeas, ignoring any differences in cost of production.

Table 5. Average yield and price for wheat and chickpeas (gram) in
India for the agricultural years, 1950 to 1970

Crop 1950 1960 1965 1968 1969 1970

Avg. yield, lbs/acre 591 759 738 1043 1079 1159
Price RO/Quintal 97.0 97.1 1068 104.5

Avg. yield, Ibs/acre 430 601 469 541 639 600
Price RO/Quintal 93.2 101.5 99.0 108.1

Source: Bulletins of Food Statistics, Ministry of Agriculture, New Delhi, India.

This comparison is not entirely valid as the two crops are not completely
competitive. Wheat is grown under irrigation where this is possible, while chickpeas
are more commonly grown under rain-fed conditions. The illustration, however,
emphasized the point that without substantial increases in yield or without some
differential pricing structure substantial increases in legume acreage may be difficult
to achieve on a sustained basis.


In conclusion, the prospects of developing food legume types superior in yield to
those in common use appear excellent. Improvements in quantity and quality of
protein appear equally feasible. Either of these developments would contribute
greatly to a lessening of the protein deficiency problem. The extent'to which these
possibilities are achieved will depend upon continued resources being allocated to
needed research.

Priority support should be provided to the eight most extensively grown food
legumes whose prospects appear comparatively brightest for more and better protein
production on a world or regional basis. Current average protein production
performances per hectare for the eight major food legumes for specific countries or
regions serve as a beginning for any overall food legume improvement program
(Table 6).

For the greater part of Latin America, to help alleviate the problem of protein
deficiency, no national or regional program supporting research, training, and
production, could exclude the bean. Beans have been and will continue to be for
some time a major supplier of protein in that part of the world. It is apparent,
however, that as a first priority special effort will be necessary for all concerned to
concentrate on the development of improved strains and supporting cultural practices
which result in economically competitive yields when compared to other crops
grown, while at the same time retaining or increasing their consumer acceptability
and nutritional value.

Table 6. Comparative production levels of protein nutrition in kg/ha for Latin America
and centers of most extensive cultivation

Crop Latin America Center of most
extensive cultivation

Soybeans 248 425 (USA)
Groundnuts 163 90 (India-Pakistan)
Dry beans 61 69 (Brazil)
Dry peas 78 174 (USSR)
Chickpeas 77 74 (India-Pakistan)
Broadbeans 57 94 (Mainland China)
Cowpeas 79 (Nigeria)
Pigeon peas 57 54 (India-Pakistan)

To accomplish this, actual protein yields per hectare of beans will have to be more
than doubled in Latin America to be on a par with the cereals; more than tripled to
be on a par with the groundnut; and more than quadrupled to be on a par with the
soybean. Thus, where the soil and climatic environments appear appropriate for the
culture of soybeans and groundnuts, the researcher-production team may find these
two crops the quickest route to increased production of quality protein and deserving
support accordingly.

For the more humid environments where limiting disease and insect pests also do
well, special consideration may have to be given to the cowpea, pigeon pea and
possibly other species. While the present farmer yield level of protein nutrition per
hectare is hardly that of the other food legumes considered worthy of research
support, their prospects of improvement appear to be as great as for the bean.
However, as with any of the food legumes, advancements will only come with a
continued and expanded research effort with central direction.


1. Hartwig, E. E. 1969. Breeding soybeans for higlr protein content and quality. New
approaches to Breeding Improved Plant Proteins. International Atomic Energy Agency,
pp. 67-70.

2. Kelly, J. F., Firman, A., and Adams, H. L. 1971. Microbiological methods for the
estimation of methionine content of beans. Rpt. 10th Dry Bean Res. Conf. ARS 74-56,
pp. 84-90, U. S. Dept. Agr.

3. Krober, O. A., Jacob, M. K., Lal, R. K., and Kashkary, V. K. 1970. Effects of variety and
location on the protein content of pulses. Indian Jour. Agr. Sci. 40: 1025-1030.

4. Leverton, Ruth M. 1959. Amino acids. 1959 U. S. Yearbook of Agr., pp. 64-73.

5. Roberts, L. M. 1970. The food legumes: recommendations for expansion and acceleration
of research. Rockefeller Found. (Mimeo. report).

6. Rutger, J. N. 1971. Variations in protein content and its relation to other characters in
beans (Phaseolus vulgaris L.). Rpt. 10th Dry Bean Res. Conf. ARS 74-56, pp. 59-69. U. S.
Dept. Agr.

7. Schertz, Lyle P. 1971. Economics of protein improvement programs in the lower
income countries. FED Report, p. 51.

8. Silbernagel, M. J. 1971. Bean protein improvement work by USDA Bean and Pea
Investigations. Rpt. 10th Dry Bean Res.-Conf. ARS 74-56, pp. 70-83. U. S. Dept. Agr.

9. Yohe, J. M., Watt, E. E., Bashandi, M. M., Sechler, D. T. and Poehlman, J. M. 1971.
Evaluation of mung beans (Phaseolus aureus, Robx.) strains at Columbia, Missouri in 1970.
Mo. Agr. Exp. Sta. Misc. Pub. 71-4. 31 pp.

10. Yohe, J. M., Swindell, R. E., Watt,E. E., Bashandi, M. M.,Sechler, D. T. and Poehlman,
J. M. 1972. Evaluation of mung beans (Phaseolus aureus, Roxb.) strains at Columbia,
Missouri. Mo. Agr. Exp. Sta. Misc. Pub. 72-9.


Ricardo Bressari
Marina Flores
Luis G. Elfas

Discussants: J. E. Dutra de Ollveira and Nelson de Souza


Leguminous grains have been recognized as important sources of protein in the
diet of populations of many tropical areas of the world. As the production of meat,
milk, eggs and fish increases slowly, legume foods offer a way to bridge the problem
of an enlarging protein gap. They can easily cover the amount of protein that is
needed, and what is probably more important, they may, when properly consumed,
provide the quality of protein highly desirable for the feeding of vulnerable
population groups infants, children, pregnant and lactating mothers.

These foods are generally accepted and consumed by all populations, including
those in areas where animal protein foods are more available. Therefore the task of
supplying more protein through legume grains is in many ways easier than other
approaches. In spite of these well known and accepted general facts, legume grains
have been, in a way, regarded as more of a laboratory curiosity because of their
protein and antiphysiological factors, than as food which can provide significant
amounts of nutrients. Furthermore, the efforts of agricultural scientists to improve
on them, are far behind their achievements with cereal grains, oilseeds, fruits and
vegetables. Today, however, the food problems of the world, particularly the
protein problem, make it mandatory to increase research in all aspects of legume
grains from production to consumption.


Information on the intake of legume grains is not easily obtained and available
data comes mostly from production records. However, there is some reliable
information from dietary surveys. Granting limitations inherent in these statistics,
values reported from both sources for Latin American countries are listed in Table 1.
The table also includes information on the total dietary intake of calories and
protein, as well as from legume grains specifically (1).

Table 1. Legume grain intake in Latin American countries, excluding soybeans and peanuts

Legume Food
Country Intake Calories Proteins Total Total
g/day /day /day intake intake
calories protein
cal/day g/day

Argentina 6.3 20 1.3 2,820 81.6
Bolivia 5.6 19 1.3 1,840 47.9
Brazil 64.4 220 14.8 2,780 66.3
Chile 27.1 92 5.8 2,410 77.2
Colombia 11.4 38 2.6 2,160 51.9
Costa Rica 27.3 93 6.0 2,430 53.9
Ecuador 26.3 91 6.1 1,890 48.4
El Salvador 31.6 108 7.1 2,030 56.7
Guatemala 23.3 80 5.3 2,080 55.4
Honduras 29.9 102 6.6 2,080 53.7
Meico 54.7 208 12.0 2,610 71.9
Nicaragua 72.0 245 17.3 1,986 64.4
Panama 24.0 82 5.2 2,310 58.1
Paraguay 30.6 105. 7.1 2,560 64.1
Peru 26.2 91 5.8 2,230 55.9
Uruguay 9.0 28 1.8 3,220 104.3
Venezuela 29.6 100 6.5 2,310 58.7

Source: Food Balance Sheets 1960-62. FAO, Rome, 1966.

One could conclude that except for three or four countries of the 17 listed,
legume grains are a significant part of the people's diet. However, the intake is really
not as high as desirable, probably for reasons other than lack of acceptance or
because they do not belong to the area's food patterns. The reasons probably lie in

The value reported is for the whole country; however, it has often been reported
that different areas within a country show higher consumption rates. For example,
in Venezuela for 1966, the national average intake was 26 g per person per day,
represented by P. vulgaris, P. sativum, C. cajan and V. sinensis, while in a rural town
in the Venezuelan Andes, consumption per person was close to 71 g, mainly from
P. sativum (2). A study carried out in a coffee plantation in Guatemala showed that
children aged 18-32 months consumed 24 g/day, mothers, 79 g/day, and adult men,
91 g/day (3). These figures are significantly higher than the national average shown
previously (4).


Table 2 lists the legume grains more often consumed by the population of Latin
America. Although P. vulgaris, whether black, white or red, occupies first place in

Table 2. Legume foods consumed in Latin America

Common name
Scientific name English Spanish

Phaseolus vulgaris Garden beans .Frijol, Caraota,
Poroto, Habichuela
Phaseolus angularis Adzuki Judia
Phaseolus calcaratus Rice bean Judfa

Phaseolus coccineus Scarlet runner bean Judia
Phaseolus lunatus Sieva bean Judia'
Phaseolus limensis Lima bean Judia
Vigna sinensis Cowpea Frijol, Caupi
Cajanus cajan Congo pea Gandul, Guandu,
Pigeon pea Quinchoncho
Pisum sativum Alaska pea Arveja, Guisante
Cicer arietinum Chick pea Garbanzo
Lens esculenta .Lentils Lenteja
Vicia faba Broad bean Haba
Dolichos lablab Field bean Gallinazo
Lathyrus sativus -- Almorta
Lupinus mutabilis Lupin Lupino

most countries, there is color preference between countries, black coated grains are
preferred in most. Other legumes consumed, but in lower amounts, probably because
of acceptance, are Vigna sinensis, Cajanus cajan and Vicia faba. .\lso consumed in
lower amounts, but for reason of price are Lens esculenta, Cicer arietinum and
Pisum sativum.


Food habits or acceptance patterns are formed early in childhood and like other
fundamental habits tend to resist change. The acceptance pattern for legume grain
consumption is clearly shown in Figure ] (5). The values represent the average of
dietary surveys in three towns in Guatemala. They show that legume intake in one
form or another begins early in childhood. Consumption of P. vulgaris broth,
relatively high at first, decreases with age, while the intake of the cooked grain

This pattern, which from the nutritional point of view is highly desirable, is not
necessarily stable, and it is changing mainly due to the low availability and consequent
high price of P. vulgaris The relatively low intake of beans by children is not peculiar
to Guatemala. but is a practice of mothers almost everywhere where beans are
consumed. For example, Martinez and Chivez (6), indicated that in a very poor

I PE. vulgaris

Ref.: Flores, M., A. Flores and M. Y. Lara.
J. Amer. Diet. Assoc. 48: 480, 1966.

1 2 2-3 3-4 4-5 Adults
Age (years)

Incap 73-95

Figure 1. Relationships between the intake of some P. vulgaris food preparations
and age.

Mexican rural community, mothers did not feed any beans to children aged 3 to 24
months. However, when an educational program was initiated, at least 50 percent
of the mothers accepted beans as a food for their children. Similar observations have
been reported from other countries, for example in Jamaica, where children one to
six years of age consume from 2.6 to 5.3 g of legume grains per day (7).

Because of their low availability, the frequency with which legumes are consumed
is far less than daily, particularly in very poor communities, as shown in Table 3. The
data in the table come from continuous dietary surveys performed in Santa Maria
Cauque, in the highlands of Guatemala (8). About 37.0 and 49.0 percent is
consumed by the mother and father, respectively, and the difference by the other
four family members. On this basis, the four young members, who need more
protein of better quality, would get only 8 to 10 g per serving, the two adults, 85
to 113 g per serving.

Frequency of intake is important for most nutrient sources if they are to make a
nutritional impact on the quality of the diet. An example is shown in Table 4. In
this study, carried out with young rats, fed a maize diet, soybean protein was fed
daily, every two and every three days. The results show a favorable relationship
between frequency of intake and weight gain ofPthe animals, and between frequency
of intake and the protein quality of the diet, and utilizable protein.

Obviously, a daily intake of Phaseolus represents a higher intake of protein,
therefore more utilizable protein, than when intake is less frequent (9). The same
effect is observed in children. Table 5 presents results of a study in which Phaseolus
was fed every 3,6 and 12 hours as a supplement in a constant ratio of one part
Phaseolus to three parts maize. The effects were measured using the nitrogen balance
method. These results suggest a lack of complementation between maize and
Phaseolus protein. They suggest also the need to make Phaseolus more available if
expected to improve protein nutrition (10).

The acceptance pattern indicated by the amount of legume food consumed is
quite constant during the year for the family unit. Table 6 shows figures published
by Flores et al (11) on legume intake over a 12-year period. Intake per family varied

Table 3. Frequency of Phaseolus intake per family in Santa Maria Cauque, Guatemala/

Frequency Number of Distribution
days/week families o

2 10 12.7
3 20 25.3
4 36 45.5
5 10 12.7
6 3 3.8

Source: INCAP. Unpublished data. Garcia, B. et al. 1972.
1/ Average of 690 g Phaseolus, served in 3 meals to a 6 member family

Table 4. Effect of frequency of intake of a soybean protein supplement
on the protein quality of a maize diet -

Frequency of Avg. weight PER Utilizable
supplementation gain, g protein, %
28 days

Daily 74 2.26 6.71

Every 2 days 61 1.98 5.83

Every 3 days 60 1.84 5.42

None 35 1.49 3.47

Source: Bressani, R., L. G. Elfas and M. Flores (1971).
1/ 8% soybean flour added to basal diet when supplemented.

from 1 48 to 54 g per person per day, while intake for 3 to 5 year old children, varied
from 10 to 14 g. During the same period, production increased about 25 percent
while prices increased from $0.07 to $0.10 per pound. The relatively low production
increase, together with the higher price and population in the country, may explain
the constancy of intake.


Since P. vulgaris is the most accepted legume grain in Latin America, more
discussion will be given to its preparation than to other legume foods. Figure 2
represents schematically the process of cooking and food preparations obtained.

Table 5. Effect of frequency of Phaseolus intake on nitrogen balance in children1 2/

Nitrogen balance
Frequency Intake Absorbed Retained Absorption Retention
mg/kg/day % intake

Every 3 hrs 326 209 74 64.1 22.7
Every 6 hrs 340 211 61 62.0 17.9
Every 12 hrs 310 202 50 65.2 16.1

Milk 322 260 55 80.7 17.1

Source: INCAP. Unpublished data. Wilson, D. et al. 1964.
1/ Nine children, aged 2-6 years, weight 9.30-23.20 kg.
2/ Ratio of maize/Phaseolus intake: 3 parts maize to 1 part Phaseolus.

Table 6. Phaseolus vulgaris consumption in rural Guatemala


Year Family Child

1953 54
1956 54
1959 51 10
1960 52 14
1961 48 10
1962 53 11
1965 50 13

Sources: Flores et al. 1955, 1957, 1964, 1966.

For P. vulgaris the grains are placed in sufficient water to cover them, with additional
water to allow for absorption and evaporation. Onions and other flavoring ingredients
are usually added and cooked at atmospheric pressure for four to five hours until
soft. The bean broth, if available, is consumed as a soup with rice, cubes of toasted
bread or other such food. The cooked beans may then be consumed as such, usually
with plantains, rice or maize in the form of tortillas, or by crushing and straining,
strained beans are prepared. These are then mixed with fat to make fried beans. The
changes in chemical composition and nutritional value are shown in Table 7. Some
crude fiber is lost during straining and fat content increases as expected in fried
beans. Cooking improves protein quality through destruction of antinutritional
factors, but fried beans show a slightly lower value, probably due to destruction of
some essential amino acids, such as lysine and/or methionine (12). There are variations
to the above cooking process, particularly addition of salts, sodium chloride and
sodium bicarbonate. In most countries, fried beans are more popular with the

Table 7. Protein quality of bean preparations in Guatemala

Processing Avg. weight PER Available Protein Fat Crude
product gain, g lysine fiber
g/16 g N

Raw beans 0 5.83 24.6 1.9 4.6
Cooked beans 34 1.24 6.30 24.9 0.7 2.8
Bean broth 1.9 0.1 0
Strained beans 37 1.43 6.35 24.0 0.6 1.6
Fried beans 10 0.87 5.17 17.8 13.3 1.6
Casein 130 2.73 -


water to cover grain
allowed to soak
4-5 hours atmospheric pressure or
i 20-30 min. 16 Ibs. pressure

Cooked grain
Broth ) consumed or discarded

Cooked grain (including broth)

Smashed, strained

seed coats strained Phaseolus

Addition of fat or
oil cooking

Fried Phaseolus

Incap 73-91
Figure 2. Home cooking process and food preparations of Phaseolus vulgaris in

Other legume grains are similarly prepared, but some are eaten differently. For
example, Vicia faba may be consumed immature but is often allowed to mature and
then toasted. The toasted seed is ground into a fine powder and used to prepare cold
"drinks. C. cajan, also consumed when dry, in areas where it is consumed is also
prepared in the immature form as garden peas (13).


Legume grains known to contain antiphysiological factors have received the
. attention of many investigators. Table 8 lists such factors which, it should be clear,
are not universally found in all legume grains (14, 15). Furthermore, the concentration
of such substances is not the same for all edible legume grains.

The most common of such factors are the trypsin inhibitors. These
antiphysiological factors are important chiefly in raw legume grains, since heat
processing destroys them in most cases. These substances are rich sources of cystine,
a semi-essential amino acid which may replace part of the methionine needs of
monogastric animals. Since legume grain protein is methionine deficient, the
presence of cystine may be of nutritional benefit. Therefore, it has been suggested
that selection of legume grains for higher trypsin inhibitor content might be useful
in increasing the protein quality of legume grain protein (16). However, Jaff6 and
others, have indicated a negative relationship (17, 18). Most, if not all, of the studies
of trypsin inhibitor activity in legume grains have concerned monogastric animals,
particularly rats; however, some species such as poultry are not as sensitive and it
has been indicated that such an antiphysiological effect is not detectable in humans
(19). This point, however, should be studied.

Ilemaglutinin compounds are also present in most legume grains, characterized by
causingblood clotting. As these are assumed to be destroyed by heating, their
importance is only in raw grains. Recent results show, however, that in some
situations cooking does not destroy all hemaglutinin activity (20).

The goitrogenic factors and cyanogenic glucosides are less well known
antiphysiological factors in legume grains and as is the case for trypsin inhibitors
and hemaglutinin compounds they are destroyed during heat processing (15).

Lathyric factors present in L. sativus constitute a serious problem in areas where
such a legume is consumed. Much work has been done on the identification of the

Table 8. Antiphysiological factors in legume grains

Trypsin inhibitors
Amylase inhibitors
Cyanogenic glycoside
Goitrogenic factors
Flatulence factors
Lathyric factors

responsible compounds and mode of action. The same is also true for favism, a toxic
compound present in Vicia faba, a legume grain produced and consumed in Central
America, and for toxic alkaloids of bitter taste found in Lupinus mutabilis, a
legume grain consumed in Ecuador (21, 22).

Flatulence factors have received much attention in recent years, particularly in
soybeans. These compounds are not destroyed by heat processing, and for many
people, they probably limit the intake of beans. Consumption of beans in some cases
has increased flatulence from 16 cc/hr to about 190 cc/hr. Along with the volume
increase, CO2 content rises from a normal value of 10 to 12 percent to above 50

Evidence suggests that the primary cause of flatulence may be the production of
gas by gram-positive, anaerobic bacteria present in the intestinal tract, after
stimulation by unknown factors in dry beans. The microorganism Clostridium
perfringens has been shown to be the primary source of gas, and it is the main
intestinal anaerobe. The unknown factors utilized by the bacteria may very well be
low molecular weight carbohydrate fractions present in legume grains, including
sucrose, stackyose and raffinose (23, 24, 25). Recently, it has been reported that
processing may decrease to variable degrees the flatulence factors in some legume
grains (26).

Up to now, mention has been. made of the antiphysiological factors in
legume grains. However, some relatively recent reports show that they have a
hypocholesterolemic property; that is, they decrease blood cholesterol levels.
Studies in the United States and in India have shown that individuals consuming
cooked beans, such as P. vulgaris, or Cicer arietinum, had lower serum cholesterrc
levels than those who did not. The factors responsible are not known. Some
workers have suggested legume grains have a carbohydrate fraction which causes
such a decrease in cholesterol (27). However, it should be pointed out that the
lipid content of beans is highly unsaturated, although present in low amounts (28).

Legume grain contain other factors not yet even well classified, which may
cause pathological effects when consumed raw. For example, it has been noticed in
pregnant ewes, rats and chicks that feeding of raw beans causes muscular dystrophy,
increasing vitamin E. requirements. These compounds however, are sensitive to heat,
therefore are destroyed during processing (29, 30).


Most people recognize that beans are difficult to digest and may give rise to
stomach upsets. Nutritionists are aware that they have a low protein digestibility.
Information on this particular problem is limited. It is not known whether these
effects are caused by a more rapid movement of the cooked legume through the
intestinal tract or by resistance to protein hydrolysis by the gastrointestinal
enzymes. In any case, significant losses of nitrogen occur in feces when beans are

Table 9 summarizes the results of studies on human adults fed Alaska split pea
(Pisum sativum) (31). Similar observations have been made in children. Table 10
shows results of various studies of children fed Phaseolus vulgaris in combination
with other foods. Fecal nitrogen increased as milk-protein nitrogen intake decreased.
Not all the effect can be attributed to bean protein, since it was given in

Table 9. Fecal nitrogen and apparent protein digestibility of human adults fed egg
protein and split peas with and without methionine addition

Nitrogen, g A
Protein source Intake Urine Fecal Absorbed Retained prot. dig.

Split pea
Split pea + met

4.90 0.81 4.79
4.62 1.16 4.31
4.21 1.19 4.76

Source: Esselbaugh et al. 1952.

combination with maize. However, nitrogen losses increased, and beans may be
responsible to some degree (32).

Results in the lower section of Table 10 were obtained from young dogs. The
intake of beans equalled 32 percent of total nitrogen, and with these relatively
small amounts of beans, fecal nitrogen increased from 36 percent to 40 percent of
the nitrogen intake (32).

Additional information for children summarized as nitrogen balance data is
shown in Table 11. In these results (33), fecal nitrogen for milk was equivalent to
19 percent of milk nitrogen intake. On the other hand, for beans, fecal nitrogen was
equivalent to 36 percent of nitrogen intake. Nitrogen loss in urine is quite similar
for both protein sources. Therefore it may be concluded that the lower retention of

Table 10. Fecal nitrogen from children and young dogs fed various
protein containing cooked beans

Diet Intake Fecal % Fecal N
mg/kg/day of N intake


Milk 387 70 18.1
25% Milk
+ 75 (maize +beans) 358 98 27.4

10 Milk
+ 90% (maize+beans) 353 134 38.0

100 %(maize+beans) 347 107 30.8

Maize 520 189 36.3

Maize + black beans 635 254 40.0


nitrogen is due mainly to the significant losses of nitrogen in feces, rather than to a
poorly balanced absorbed protein. The author indicated that in comparison with the
number of bowel movements from milk, used as reference, bean consumption
increased bowel movements by six. There was also an increase in the weight of feces
when beans were ingested (33).

These findings indicate again some of the reasons for the lower digestibility of
beans. However, the fundamental factors are not known. Studies with rats have
shown accelerated food passage when beans are consumed. Furthermore, the
cotyledons and not the seed coat were responsible (24).

The low protein digestibility of legume grains has been observed not only as
among species, but also among varieties of the same species; see Table 12,Jaff6 (34).

No experimental results permit us to estimate with precision the variability of
protein digestibility of the various bean cultivars, which would allow us to select
varieties with higher values. It is possible that grain size has a significant influence,
since small seeds have heavier cotyledons.

Recently, Seidl et al (18) obtained a protein fraction from'black beans that was
resistant to in vitro digestion by 10 proteolytic enzymes, even after protein
denaturation, and that was inhibitory to trypsin and papain. It is not known if such
a protein is present in all legume grains. The classical trypsin inhibitor is thermolabile,
so it follows that it cannot be responsible for the low digestibility of protein
observed in some species and varieties of beans.


Because legumes are nutritionally important among vegetable foods for their
relatively high protein content, attention is given here only to that nutrient.

Protein content of edible species of legume grains, excepting soybeans and
groundnuts, varies between 18 to 32 percent. The cotyledons contain about 27
percent protein, while the embryonic axes and seed coat contain 48 percent and
5 percent, respectively. Cotyledons contribute the largest amount of protein because
of their greater weight. Salt-soluble globulins are the predominant class of proteins
in seeds of Phaseolus and some of these have been shown to be resistant to
hydrolysis by proteolytic enzymes. The presence of such proteins in legume grains
may explain the low digestibility of legume grain protein (18).

Table 11. Fecal nitrogen losses from milk and P. vulgaris fed to children

Nitrogen balance
Protein source Intake Fecal Urine Absorbed Retained


Milk 236 46 116 190 74

Cooked black beans 227 81 109 146 37

Source: Data from Rosales Arzi, A. M. INCAP (1972).

Table 12. True protein digestibility of legume grain species and varieties

Iegume grain True protein
digestibility, %

Phaseolus vulgaris (black) 76.8
Phaseolus vulgaris (white) 84.1
Phaseolus vulgaris (pink) 79.5
Vigna sinensis (black) 90.0
Vigna sinensis (beige) 86.4
Pisum sativum (green) 90.7
Pisum sativum (yellow) 93.9
Cajanus indicus 90.5
Cajanus indicus 59.5
Lens esculenta 92.6
Cicer arietinum 90.5

Source: Jaffe, W. G. (15).

In addition to species differences, other factors have been shown to affect the
content of protein as well as other nutrients, including essential amino acids. Table
13 summarizes the results of one study carried out with 25 varieties of Phaseolus
vulgaris. The protein content ranged from 20.1 percent, to 27.9 percent, and was
influenced significantly by both variety and location. Methionine varied from 0.17
percent to 0.33 percent, lysine from 1.69 percent to 2.42 percent, and tryptophan
from 0.14 percent to 0.22 percent. This variation was the result of both, varietal
and location factors, except in the case of methionine, where varietal differences
were not significant.

This particular study found that the intervariety coefficients of correlation
between pairs of these nutrients were all positive and that a majority of them were
highly significant. This implies that genetic factors that cause one nutrient to
increase effect an increase in other nutrients as well (35).

The essential amino acid content of legume grains has been studied many times.
Representative values indicating the variations reported are showfi in Table 14. Eor
comparative purposes, the table also shows values for beef, since beans have been
called "the meat of the poor." This table shows that legume grain protein is high in
lysine content, a factor of much nutritional significance when beans are considered
as supplements to cereal grains. A second factor of interest is that they are low in
total sulfur-amino acid content, which also is important when considered in terms
of diets based primarily on such roots as cassava. The next amino acid of special
interest is tryptophan with relatively low values.

Amino acid content of legume grains depends on species, varieties, localities,
and management practices. Of particular significance are the results of application of
minor element fertilizers. For example, it has been shown that the uptake of zinc

Table 13. Analysis of variance of nutrient content of bean varieties grown in two localities

Mean square

Source of D. F. Nitrogen Methionine Lysine Tryptophan

Varieties 24 0.560** 0.009 0.193* 0.003**
Localities 1 2.869** 0.189** 0.998** 0.041**
Var x loc 24 0.090** 0.006** 0.091** 0.001*
Reps within
loc 4 0.016 0.0002 0.021 0.0002
Exptl error 96 0.024 0.001 0.019 0.0002

Source: Tandon et al. (35).
Statistically significant differences at the 5 % level of probability.
** Highly significant differences at the 1 % level of probability.

by the pea bean causes increases in methionine. In another study, Pisum sativum
fertilized with sulfur, increased methionine content from 1.29 to 2.18 g per 100 g
of protein (11).

The nutritive value of legume grains also has been studied extensively. Biological
value, representing the amount of absorbed nitrogen retained in the body, has been
found to be variable and low in most legume grains. Some representative results are

Table 14. Range in essential amino acid content in species and varieties of legume grains

Amino acid Range Beef
g/ g N g/ g N

Arginine 0.36 0.57 0.40
Histidine 0.08 0.21 0.22
Isoleucine 0.32 0.62 0.33
Leucine 0.20 0.68 0.51
Lysine 0.34- 0.71 0.55
Methionine 0.03 0.11 0.15
Cystine 0.01 0.07 0.08
Phenylalanine 0.15 0.49 0.26
Threonine 0.16 -0.31 0.28
Tyrosine 0.06 0.24 0.21
Tryptophan 0.01 0.07 0.07
Valine 0.24 0.49 0.35

Table 15. Biologic value of some species and varieties of legume grains

Legume grain Biologic value

Cajanus cajan 46 74
Phaseolus vulgaris (black) 62 68
Vigna sinensis 45 72
Cicer arietinum 52 78
Lens esculenta 32 58
Phaseolus aureus 39 66
Phaseolus mungo 60 64
Pisum sativum 48 49

shown in Table 15. Values range from 32 percent to 78 percent, and large variations
are also observed for varieties of the same species (34, 36). It is difficult to explain
such high variability because many factors are involved. However, it is highly
probable that the main factor is the relatively low concentration of sulfur-amino
acids in legume grains.

The beneficial effect of the addition of methionine to beans has been shown
many times (11). Table 16 summarizes some results. Addition of 0.3 percent
methionine increased the protein efficiency ratio in every case, but not equally
among all species. This small effect of methionine addition in some cases may be
explained on the basis that methionine is not the most or the only limiting amino
acid in some legume species.

Table 16. Effect of methionine addition to various species and varieties of.legume grains

Protein efficiency ratio
Legume grain -Methionine +Methionine

Phaseolus vulgaris (black) 0.0 0.9 3.5 3.8
Phaseolus vulgaris (red) 0.0 1.7
Phaseolus vulgaris (white) 1.2 2.7
Vigna sinensis (black) 1.0 1.6
Vigna sinensis (beige) 1.0 1.8
Pisum sativum (green) 0.3 2.7
Pisum sativum (yellow) 0.0 1.2
Lens esculenta 0.0 0.9
Cicer arietinum 1.7 2.8

Source: JaffW, W. G. (17).

Table 17. Amino acid supplementation to Cajanus indicus

Amino acid Amount added Avg. wt. PER
gain, g

None 48 1.82
DL-methionine 0.1 35 1.52
DL-methionine 0.3 30 1.32
DL-tryptophan 0.1 58 1.81
DL-methionine 0.2

118 2.65
DL-tryptophan 0.1

Source: Braham et al. (37).

The results in Table 17, obtained with Cajanus cajan, show that methionine
addition has no effect on improving protein quality. The same is true if only
tryptophan is added. However, when both amino acids were added, protein quality
increased, which indicates that, at least in Cajanus, both amino acids are about
equally limiting (37). The same sort of situation may exist with other legume
grains, particularly with those that do not respond significantly in protein quality
improvement when supplemented with methionine.

The protein quality of legume grains can also be affected by other factors, such
as storage, and processing. These two post-harvest factors may have played important
roles in the nutritive value reported by various workers. Legume grains contain
antinutritional factors which are destroyed by cooking, and cooking may decrease
protein quality. So it is possible that if processing is not carried out under equal and
standardized conditions, it may contribute to the variability in the biological value
reported in the literature.

Storage affects cooking quality, because it is common to find hardshell beans in
stored beans. Hardshells require longer cooking, which may decrease protein quality.
Therefore, it is suggested that optimum cooking conditions should be established
for each legume grain species, in order to reduce the variability in nutritive value as
determined biologically. This will be of value for agronomic and nutritional
improvement programs. Furthermore, care should be taken to compare bean species
and varieties that have been under equal storage conditions.


Among vegetable crops, legume grains contain the highest amounts of protein, in
general well above twice the level in cereal grains, and significantly more than in
root crops. The protein of the legume grains is considered to be a rich source of
lysine. Sulfur-containing amino acids are the major amino acid deficiency. Cereal
grain proteins are low in lysine but have adequate amounts of the sulfur-amino acids.
It is evident that legume grain protein is the natural supplement to cereal grain
proteifis. If this is accepted, any nutritional improvement to be done in legume

foods must consider the nutritional role they play indiets,based on cereal grains and
starchy foods. In the specific case of edible roots such as cassava and other starchy
foods such as plantain, legume grain protein may constitute the only source of

The supplementary effect of legume protein to cereal grains is well documented.
On a dry-weight basis, the level of beans usually represents about 10 percent of the
dry weight in diets, at least those eaten in Central America (4, 5). Therefore, in the
results presented in Tables 18 and 19, the diets fed to rats were prepared with 90
percent cereal and 10 percent black beans (P. vulgaris). The resulting performance
was compared with that from diets which contained 100 percent cereal grain

The effect of beans in increasing utilizable protein in cereal-legume mixtures is due
to an increase in protein quality as well as to a higher protein content. This is shown
in Table 18, in which protein content is equalized to about 7.5 percent among
dietary treatments. Even though the presence of 10 percent beans in diets increased
the protein quality of the cereal, the increases were larger for those cereal grains
poorer in protein quality, such as maize and sorghum, followed by wheat, rice and

The results when protein content of the diet was not adjusted to a fixed level are
shown in Table 19.

Table 18. Percent utilizable protein from cereal fed alone and from 90 percent
cereal +10 percent bean mixtures

Protein source Protein in Utilizable
diet, % protein, %

100 % Rice 6.9 4.01
90 % Rice + 10 % Beans 7.9 4.96

100 Maize 8.5 2.41

90 %Maize + 10 O Beans 10.3 4.10

100% Sorghum 7.7 2.23

90 % Sorghum
+ 10% Beans 8.6 3.93.

100 % Whole Wheat 11.0 4.26

90% Wheat
+ 10 ,Beans 12.0 5.94

100 Oats 13.8 8.22
90 % Oats
+ 10 % Beans 14.6 8.73

Casein 10.7 8.02

Table 19. Protein quality of cereal grain and of cereal grain-bean diets
fed at equal levels of dietary protein

Protein source Avg. wt. PER
gain, g

100 % Rice 43 2.15

90 % Rice
+ 10% Beans 56 2.32

100 Maize 13 0.87

90% Maize
+ 10% Beans 32 1.40

100 % sorghum 12 0.88

90 %o Sorghum
+10 Beans 30 1.39

100 Wheat 19 1.05

90g Wheat
+ 10% Beans 41 1.73

100 Oats 34 1.60

90 goOats
+ 10% Beans 75 2.37

Casein 75 2.71

Table 18 shows two results of interest. One is the increased protein content of
the diets when they contained 10 percent bean. This is a significant increase,
particularly for children, who require relatively higher protein intakes than do adults
but have a smaller stomach capacity. The second point of interest can be seen
under the utilizable protein column, which is higher for diets made with cereal and
beans. It is also of interest to see that higher increases in utilizable protein are
obtained from the cereal-bean mixtures when the cereal is of a low protein quality-
as for example, maize, sorghum, wheat, rice and oats, in that order.

The term utilizablee protein" means the product of protein quality and protein
content relative to a reference protein, which in the present case was casein.

The evidence presented serves to propose at least two factors that should be
considered in bean quality improvement programs. First is the desirability for higher
protein concentration in legume grains, which becomes more significant in terms of
child feeding. Second, such protein should be higher in lysine content, as this amino
acid is limiting in all cereal proteins tested. Even though lysine is not the only
limiting amino acid in cereal proteins, increased protein content in beans will carry


Table 20. Amino acid supplementation of maize-bean diets.

Dietary treatment Avg. wt. gain PER
g/28 days

Maize +Beans--' 69 2.11

Maize+ Lys+ Try
+ Beans,2/ 103 2.64

Maize + Beans
+ Met3/ 66 1.93
Maize + Lys + Try2/
+Beans+ Met 3 108. 2.69

Maize 32 1.21

Maize + Lys
+ Try" 100 2.68

1/ 72.4f maize+8.1 %beans.
2/ 0.30%L-lys HCI +0.10 DL-try.
3/ 0.30%DL-met.
4/ 0.406%L-lys HCI + 0.10oDL-try.

with it more tryptophan, threonine, and methionine-amino acids that are somewhat
deficient in the cereal grain protein.

Even though the presence of 10 percent beans increases the protein quality of the
cereal, such mixtures are still deficient in the same amino acids as the particular
cereal under consideration. However, the amounts needed are lower. The information
in Table 20 supports these statements. Maize alone shows a significant response to
the addition of lysine and tryptophan; these two amino acids also improve the
quality of the mixture of maize and bean under consideration (38). Addition of
methionine to beans, whether or not maize is supplemented with lysine and
tryptophan, does not improve the quality of the protein. Similar results have been
observed with rice-bean mixtures, in which bean contributes about 10 to 12 percent
of the dry weight of the diet.

The above information is presented to indicate that any consideration given .to
improving the nutritive quality of beans must be based on the fact that they are
eaten together with other foods, cereal grains in particular. In this respect, it is of
interest to analyze the results in Table 21. This study seeks information on what
changes should be introduced into beans to obtain cereal-based diets with higher
protein quality.

The results were obtained by changing those nutritional characteristics in beans
that would be reflected in. better quality protein diets. Adding beans to a maize diet
improves protein content and protein quality.

Table 21: Effect of various dietary treatments of beans on the protein quality of corn bean diets

Dietary treatment Protein in Protein Utilizable
Avg. Wt.
diet, % 'Maize Beans gain protein
% o g/28 days

100 % maize 8.7 100 0 25 2.93

87'% maize + 13 % beans 10.6 71 29 48 4.54

74% maize + 26% beans 12.3 51 49 86 6.26

87 %inaize + 13 % beans/ 12.3 62 38 72 5.87

87 %. maize + 13 % beans2/ 12.8 59 41 94 7.09

87% maize + 13% beans3/ 10.5 71 29 71 5.45

1/ Bean with a protein content 1.5 times the protein content of common beans.
2/ Bean with a protein content 2.0 times the protein content of common beans.
3_/ Bean with a higher lysine content than common bean.

In treatment 6, bean intake and protein content were maintained as found in
nutritional surveys. However, the bean protein simulated in this case represented
one with a lysine content higher than normal. The results indicated that this was
as adequate a change in bean protein composition as were the other modifications

For practical purposes, the data shown in this and other tables suggest that the
protein quality of cereal-based diets could be much improved if the intake of beans
could be increased through increasing their availability and reduced prices provided
of course, that there are no physiological factors limiting the intake. Likewise, the
data suggest that beans containing higher protein or those containing normal
protein with higher lysine levels could be nutritionally beneficial to populations who
consume ceieal-based diets. This applies particularly to preschool populations, where
nutrition problems seem to be concentrated. Any alternative should be as good, and
it is up to the agronomist to concentrate on one of the possibilities. Let me
emphasize, however, that it is not advisable to generalize, because the situation
recommended is (a) for populations consuming maize, (b) when beans contribute
about 13 percent of the dry weight of the diet, and (c) when the legume food is
Phaseolus vulgaris.

Some information is also available for cassava-based diets. Results are shown in
Table 22. Beans with or without methionine addition improve growth performance,
as indicated by lower weight loss in a 28-day experimental period. The results were
expected, because dietary protein is about 4.6 percent, a level too low for growing
weanling rats. The solution would be to increase the intake of beans, and the beans
utilized should have a higher menthionine content.

Table 22. Effect of small amounts of legume grain on the
nutritive value of cassava-based diets

Dietary treatment Protein Avg. wt.
% gain, g

Cassava (100) 1.8 -13

Cassava + beans (87/13) 4.6 7

Cassava + beans
+ met (87/13/0.3) .4.6 6

As shown in Table 23, manioc flour diets with and without methionine were
tested in the presence of three levels of beans in the diet. Protein intake was higher
as the percentage of bean in the diet increases. Best performance was obtained in
every case in which methionine was present, also expected in view of the well known

Table 23. Protein quality of manioc flour with and without methionine
addition mixed with various levels of beans

Dietary treatment Protein % Avg. wt. PER
in diet gain, g

65 % manioc flour
+ 35 % bean flour 8.04 7.7 0.78

65 % manioc flour
+ 0.6% methionine
+ 35% bean flour 8.85 68.2 2.70

55 % manioc flour
+ 45 % bean flour 9.97 14.2 0.96

55 % manioc flour
+ 0.6 % methionine
+ 45 % bean flour 10.09 66.8 2.68

45 % manioc flour
+ 55 % bean flour 12.17 31.7 1.28
45 % manioc flour
+ 0.6% methionine
+ 55 bean flour 12.23 71.0 2.27

Source: Dutra de Oliveira et al. (39)

sulfur-amino acid deficiency in bean protein. Even though protein efficiency appears
to decrease as common beans increased in the diet, the percentage of utilizable
protein was essentially the same.

It must be pointed out that a recommendation for bean with a high methionine
content to complement manioc diets will depend on the actual amount of bean
consumed by these particular populations. Although methionine addition to beans
fed to humans has resulted in improved quality (31), the levels needed are smaller
than those commonly utilized in rat studies.


It has been shown that small amounts of legume protein added to cereal grains
improve the amount of utilizable protein in the mixture. It also has been shown that
higher intake of beans with a higher protein content and beans with a higher lysine
content also could result in better quality diets. Assuming that bean production could
be easily increased and that this increased production would stimulate higher
intakes, the question would be: How much is recommendable in terms of protein

Figure 3 presents results when diets for growing rats contained equal amounts
of protein, derived in different proportions from maize and Phaseolus. Maximum
protein value was obtained when 50 percent of the protein in the diet was derived
from beans and 50 percent from maize (40), corresponding to 72 g of maize and 28
g of beans. The ratio of maize to beans is 2.6 to 1.

It is interesting that a mixture of the two components in the ratio shown has a
protein quality greater than each component fed alone. From the amino acid
content of the two components and comparison to amino acid patterns, lysine
appears to be the main limiting amino acid when maize provides from 50 percent to
100 percent of the protein of the diet. On the other hand, methionine becomes the
deficient amino acid as greater proportions of protein are provided by beans.

Some evidence to -this is shown in Table 24. The addition of small amounts of
the three limiting amino acids to maize increased protein utilization from a protein
efficiency ratio (PER) value of 1.05 to 2.47. The 50/50 mixture was improved from
2.10 to 2.42 by the addition of small amounts of lysine and methionine. The addition
of methionine, tryptophan and leucine improved the quality of bean protein, an
effect probably due mainly to methionine.

Additional results are shown in Table 25. This shows the effect of amino acid
supplementation to optimum protein quality mixtures of cereal and legume grains.
The effect of methionine supplementation is dependent on the cereal grain as well
as on the legume. For example, the mixtures of maize and sorghum with Phaseolus
vulgaris are improved when methionine is added, but this is not true in the case of
rice. On the other hand the cereals with Phaseolus lunatus are not improved in
quality when supplemented with methionine.

Similar studies have been carried out with opaque-2 maize and black beans, with
the results shown in Figure 4 (42). In this example, bean protein is still deficient in
methionine; however, though opaque-2 maize has essentially the same methionine
content as common maize, it has significantly higher levels of lysine and tryptophan.

(8-9% Protein in Diets)

Lysine Methionine
Deficient I Deficient

U0, l14 1 1-*
Corn 100 90 80 70 60 50 40 30 20 10 0
Beans 0 10 20 30 40 50 60 70 80 00 100
Protein % Distribution
in Diets
Incap 68-226

Figure 3. Optimum protein quality mixtures between maize and Phaseolus

Table 24. Amino acid supplementation of 72 percent maize and
28 percent bean mixtures

Weight distribution, % Amino Acids Avg. wt. PER
Maize Beans added gain, g

100 0 None 29 1.05

100 0 Lys-Try-Leu 74 2.47

72 28 None 51 2.10

72 28 Met-Try 59 2.03

72 28 Met-Lys 75 2.42

0 100 None -3 -

0 100 Met-Try-Leu 23 1.04

Table 25. Amino acid supplementation of cereal legume grain combinations

Weight distribution, % Amino acid Avg. wt. PER
Cereal Legume added gain, g

Maize (70)

Maize (80)

Sorghum (70)

Sorghum (70)

Rice (80)

Rice (80)

P. vulgaris (red) (30)

P. lunatus (20)

P. vulgaris (black) (30)

P. lunatus (30)

P. vulgaris (red) (20)

P. lunatus (20)







Source: Sirinit et al. (41).




120 -


100 -

90 -

80 -

70 -

60 -

50 -

40 -

30 -

20 -

10 -


Incap 72-759

Figure 4. Optimum protein quality mixtures between opaque-2 maize.and
Phaseolus vulgaris.

_ *e

I I I I 1 I
80 60 50 40 20
20 40 50 60 80

Protein in diet distribution X% bean/opaque 2 maize

Highest performance occurred when 50 percent of the dietary protein was derived
from each component. However, similar values were observed when maize
contributed greater levels of protein. On the other hand, greater levels of bean
protein in the mixture resulted in lower performance, because of an increasing
methionine deficiency. The 50/50 mixture of maize and Phaseolus vulgaris gave a
PER value of 2.1 and a weight gain of 52 g. In contrast, the 50/50 protein mixture
of opaque-2 maize and Phaseolus vulgaris gave a PER value of 2.6 with a weight
gain in 28 days of 108 g.

The experimental results show the optimum proportion of maize to beans to be
78 g of maize and 28 g of beans for a 2.6 to 1 ratio. The results of various nutritional
surveys carried out in Central America permit calculation of the actual ratio
consumed. These results are shown in Table 26 (4,5). In both adults and children,
consumption of maize predominates, which permits the conclusion that the diets'
are low in protein and deficient in lysine.

Mixtures that provide the maximum protein quality have been determined for
other cereals and legume grains (43). A summary of such results is presented in Table
27. These results suggest that the poorer the quality of the cereal the greater the
level of legume protein needed to bring about the improvement in quality. They
also suggest that cereal-based diets could be of a higher protein quality if the legume
grain intake were higher than at present.

Examination of legume intake in bean-consuming countries shows that in general,
it is relatively low -- for example, average intake levels in the Central American
countries. The highest intake is 72 g/person/day which is not enough to give a 2.6
ratio with respect to the cereal intake (5).

These and other results raise various questions. Why do people eat only these
amounts of beans? Can more beans be consumed? Is consumption limited by their
low availability, or is there a physiological limit induced by unrecognized factors, or
by a resistance to digestion? If bean consumption is to increase and help solve the
world protein deficiency, these questions must be answered.

Table 26. Average daily intake of maize and beans in various areas of Central America

Maize Beans Maize/Bean
g/day g /day ratio

Adults 423 58 7.3

Children 281 24 11.7
295 26 11.3
277 15 18.5

Adults 398 56 7.1
El Salvador
Adults 374 60 6.2

Best ratio 72 28 2.6

Table 27. Protein value of optimum combinations between cereals and leguminous seeds

Distribution of Protein
in diet, %
From cereal From beans PER Increase, %

100 rice 0 beans 2.25
80 rice 20 beans 2.62 16.4

100 maize 0 beans 0.90
50 maize 50 beans 2.00 122.2

100 maize 0 cowpea 1.22
50 maize 50 cowpea 1.84 50.8
100 wheat 0 beans 47*
73 wheat 27 beans 70* 48.9

100 maize 0 soybean 1.50
40 maize 60 soybean 2.85 90.0

Net Protein Utilization (NP U).

An attempt to answer some of them is shown in Table 28. In this study, young
rats were allowed to eat as they wished from two feeder cups placed in the cage.
One contained maize, the other Phaseolus. The maize and bean diets were modified
(second column) to permitthe rat to choose the food that was made more suitable
nutritionally. Intake from each cup was recorded (third column) and used to
calculate the maize-to-bean ratio. From the protein ingested and the protein efficiency
ratio, the percentage of utilizable protein was calculated.

The first group was fed on maize and beans without any other dietary treatment.
The ratio of maize to beans was 3.58 with a utilizable protein of 3.11 percent.

Results indicate that the animal tried to balance the quality of the protein
ingested, because the ratio of 3.6 is closer to the best ratio-2.6- found in other
experiments. When both maize and beans were supplemented individually with"
vitamins, minerals and additional calories, the animals consumed higher amounts of
maize and beans to give a ratio of 3.87, similar to that of the previous case.
Utilizable protein increased to be expected because other needed nutrients were

The third treatment stimulated the free intake of beans and also of maize. The-
increased intake of beans can be explained on the basis that the animal consumed
more to meet its needs for other nutrients. There was also an increase in maize
intake, probably needed by the rat as a source of calories to balance the increased
intake of protein from an increased intake of beans. These results also indicate that
beans do not impose a physiological limit of intake.

Table 28. Effect of various dietary treatments on the free intake of maize and bean by young rats

Foods Dietary Intake Utilizable protein
treatment g /rat /28 days Ratio

Maize None 188 3.58 3.11
Beans None 53

Maize Vit-Min-Cal 238 3.87 5.15
Beans Vit-Min-Cal 61

Maize None 257 2.08 6.24
Beans Vit-Min-Cal 124

Maize Vit-Min-Cal 250 2.65 6.19
Beans None 94

Maize Lys-Try 184 3.86 3.81
Beans Met 47

Maize Lys-Try-Vit
Min-Cal 272
Met-Vit- 2.26 6.68
Min-Cal 120

Maize Lys-Try-Vit
Min-Cal 291 2.94 6.10
Beans Vit-Min-Cal 59

Factors more directly related to protein quality were tested in treatments 5 to 8.
Adding lysine and tryptophan to maize and methionine to beans did not significantly
alter the ratio of maize to beans observed in the first group. Utilizable protein
increased slightly. When all three amino acids and other nutrients are added to the
two foods there is a high intake of both to give a 2.3 ratio with 6.7 percent of
utilizable protein. Treatment 7 improved the protein quality of maize, but not of
beans, with other nutrients present in both. This stimulated maize intake, but not
that of beans, contrary to what is seen in treatment 8, in which beans, but not maize,
were supplemented with methionine to improve protein quality. This resulted in an
increase in bean intake, but it did not differ greatly from the intakes observed in the
third treatment.

The results indicate clearly that when the rat was allowed to choose its food, it
did so by nutrient supplementation, but not by amino acids alone. Many observations
are difficult to explain, and no attempt is made to do so now. However, the results
show clearly that the animals tend to consume more beans when they are available
and that this higher intake causes no damage to theanimal. Therefore, efforts should
be made to increase production of legume grains to permit cost reductions and thus a
greater intake.

On the basis of the results presented regarding the supplementary and.
complementary effect of bean protein to cereal grain protein, as well as the effect of
amino acid addition to bean-cereal mixtures, calculations were made on the best levels
of certain essential amino acids and other nutrients which beans should have.
Consideration in these calculations.was also given to the possibility of attaining
them now or in the near future according to the variability in the nutrients normally
found in a relatively large number of samples analyzed.

The calculations based on these facts suggested that bean protein should contain
6.4 g of lysine/16 g of nitrogen, 1.2 g of tryptophan/16 g of nitrogen and 2.3 g of
total sulfur-containing amino acids per 16 g of nitrogen.

These values in bean protein will complement cereal protein efficiently. The
protein level in beans should be not less than 25 percent. The reasons behind this
figure have been outlined. Furthermore, present cereal-bean diets are low in protein
content, which makes it difficult for a child to meet his protein needs from such
diets, because they tend to be bulky. The protein digestibility of beans should be
about 85 percent. Finally, maize-bean diets have a low calorie density, and populations
consuming them also have a calorie deficiency. Therefore, it would be ideal if bean
lipid concentration was around 6 to 8 percent. An advantage of soybeans as a food
over other legume foods is their higher fat content. The lipids in beans should be
of great nutritional benefit not only as sources of calories, but as sources of essential
fatty acids.


It would appear that the most important effort to be made in bean research is to
increase the yield, which, it is hoped, would increase their availability and decrease
their cost. Significant advances have already been made in this respect in some
countries, for example, El Salvador. However, the higher yield effort may be short-
lived because of improper storage conditions, which cause hardshell in the grain, so
reducing cooking quality.

Once the above is achieved, bean research should concentrate on increasing total
protein content. Results indicate that higher levels of lysine, tryptophan and
methionine, in that order, result from higher protein-containing beans. Higher protein
content is of benefit to situations in which beans are consumed together with cereal
grain and manioc-based diets.

Attempts should also be directed toward increasing protein digestibility of some
legume grain species. The factors responsible for protein indigestibility are not
known. Trypsin inhibitors could not be totally responsible, because they are destroyed
during heating. However, it is possible that presently available techniques do not
permit assays for other heat-stable factors.

Beans with a higher lysine content might prove to be very effective in improving
the quality of the cereal diet. However, if digestibility of the protein is improved, it
is probable that the amounts now present are enough to balance the low lysine
content in cereal grains.

The flatulence factor is another characteristic of beans that should be
eliminated. It may be possible that it might be destroyed by certain processing

High methionine-containing beans also should receive attention, particularly
for those populations on manioc diets, which contribute little protein.

Higher intakes of bean protein probably could be achieved through the
preparation of stable pre-cooked products, which offer the advantages of improved
stability, lower costs of preparation, and possible additional nutrients.

Finally, it should he emphasized that for nutritive quality screening purposes, it
is essential to standardize all procedures, starting with storage, through processing
and drying to the biological assay technique. The optimum cooking procedure to
inactivate trypsin inhibitors and other heat-sensitive toxic substances probably is
not the same for all legume species or varieties, because they contain different
concentrations of those compounds. Similarly, some species have a greater tendency
than others to hardshell. Standardization and definition of the screening procedures
will speed up the nutrition role of legume grains for human populations.


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nes derivadas por solubilidad diferencial, en niios preescolares. Trabajo de tesis Escuela de Nu-
trici6n, Instituto de Nutrici6n de Centro America y Panami (INCAP), Guatemala, C. A.

34. JaffW, W. G. 1950. El valor biol6gico comparative de algunas leguminosas de importancia
en la alimentaci6n venezolana. Arch. Venez. Nut. 1:107.

35. Tandon, O. B., R. Bressani, N. S. Scrimshaw and F. LeBeau. 1957. Nutritive value of beans.
Nutrients in Central American beans. J. Agr. Food Chem.:137.

36. Patwardhan, V. N. 1962. Pulses and beans in human nutrition. Amer. J. Clin. Nut. 11:12.

37. Braham, J. E., R.M. Vela, R. Bressani and R. Jarqufn. 1965. Efecto de la coccibn y de la
suplementaci6n con aminoicidos sobre el valor nutritivo dd la protein del gandul (Cajanus
indicus). Arch. Venez. Nut. 15:19.

38. Elfas, L. G. and R. Bressani. 1971. Improvement of the protein quality of corn-bean diets
by the use of fortified corn or opaque-2 corn. In: III Western Hemisphere Nutrition Congress. Bal
Harbour, Miami, Florida, August, 1971.

39. Dutra de Oliveira, J. E. and E. B. Zappelini deMenezes Salata, 1971.Methionine fortified
manioc flour to combat protein malnutrition. Nut. Reports Int. 3:291.
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human feeding. VI. The growth promoting value of combinations of lime treated corn and.
cooked black beans. J. Food Sci. 27:394.

41. Sirinit, K., A. G. M. Soliman, A. T. Van Loo and K. W. King. 1965. Nutritional value of
Haitian cereal-legume blends. J. Nut. 86:415.

42. Bressani, R. and L. G. Elias. 1969. Studies on the use of opaque-2 corn in vegetable
protein-rich foods. Agric. & Food Chem. 17:659.

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Latinoamer. Nut.19:109.

Commentary upon:



J. E. Dutra de Ollvelra
and Nelson de Souza


We would like to make a few comments on the basis of our past work, mainly
with common beans (Phaseolus vulgaris). Brazil is the largest common bean producer
of the world and we have one of the largest per capital consumption. It can be said
that it is the staple food in Brazil. In the northeast area of the country it is consumed
mainly with manioc flour and in the south with rice.

The ICNND survey in northeast Brazil found that common beans were used at
least once daily by almost 100 percent of the families and are the most important
single source of protein in the local diet (1).

The intake of beans varies from one place to another within the northeast; a
few results of dietary surveys in that area appear in 'fable 1. Because beans are eaten
along with manioc flour in that area, we thought it would be advantageous to utilize
manioc as a methionine carrier to balance the local diet. Our initial results have been
shown by Dr. Bressani, and further studies on the same subject, including different
ratios of beans to manioc and variable amounts of methionine, have been published (2).

Table 1. Food consumption in some areas in northeast Brazil

Urban Rural area
Food Recife area A B


Beans 80 130 215 70
Rice 100 155 125 15
Manioc flour 65 125 200 330
Meat 235 105 40 70

In south Brazil, where beans are commonly used along with rice, we have
intensively studied this combination. The most common bean is the brown variety. We
have been finding in rats that the mixture with the best nutritive value is the one
with 80 to 90 percent of the protein from rice and 10 to 20 percent from beans.

We did a series of studies on amino acid supplementation of the rice and
beans mixtures. We think it of interest to report a study on self-selection of dietary
protein from rice and beans by rats (3). We confirmed that on the ad libitum intake
the animals chose a mixture of 80 percent of the protein from rice and 20'percent
from beans. It was also shown that methionine supplementation of the beans is
responsible for a three-fold increase in the total intake with a better PER. When both
rice and beans are amino acid fortified the animals gain more weight, the PER is
greater but the bean consumption is not so large as when only the bean is
supplemented (Table 2).

We have-done a few metabolic studies on children, giving them a rice and bean
diet in the same proportions as they eat at home. The nitrogen retention is not so
high and the nutritive value of the mixture can be improved when part of it is
replaced by milk or corn and soya mixture (4).

Acceptance of beans as a daily food in the south is quite good and we do not
expect a problem in this respect. Current food habits in Brazil make it unlikely that
a large intake of beans by infants and small children will occur. We believe that in
this region a bean flour or a formulated well-balanced bean mixture could be of

The price of beans in Brazil (Table 3), is not higher than other usual foods; in
terms of protein it is even cheaper.

A better contribution of beans to the human diet can be achieved by new
varieties with more methionine, or with pre-cooked products. Methionine can be
infused in beans in the pre-cooking process, as we have reported earlier (5).

Using common bean protein concentrates is another approach through which,
we thought, beans could supply protein for human consumption (6).

Also new varieties, or bean processing, that would save the three to five hours
cooking and the fuel used, could enhance bean consumption.

Table 2. Food intake and utilization of rats by self-selected diets

Food intake, g Diet 1 Diet 2 Diet 3 Diet 4

Rice 166 137 233 234
Beans 41 129 50 75
Amino acid
Rice -++
Beans + +
Weight gain, g 40 67 70 95
PER 2.71 3.51 3.39 4.28

Table 3. Price of beans as compared to other foods in Brazil (1972) *

Belem Recife Rio S.Paulo Protein

g/l00 g

Beans, kg 2.13 1.46 1.31 1.89 20-25
Rice, kg 1.50 1.73 1.89 7-8
Manioc flour, kg 0.75 1.06 1.01 1.11 0.8-1.8
Meat, kg 7.33 5.89 5.91 6.32 18-22
Milk liters 1.30 0.70 0.67 0.71 3.4-3.6

*Cruzeiros (1 dollar = 6 cruzeiros)

In summary, we conclude that beans can have a real impact on the quantity
and quality of the protein intake and diet of several areas, if interest and support
can be brought to thoroughly investigate different aspects of their utilization.


1. ICNND Nutrition Surveys Northeast Brazil, 1965.

2. Dutra de Oliveira, J. E., E. B. Z. M. Salata and J. Campos, Jr. 1973. Manioc flour as a
methionine carrier to balance common bean-based diets. J. Food Science 38: 116.

3. Souza, N. and J. E. Dutra de Oliveira. Self selection of dietary protein from rice and
beans. To be published.

4 Dutra de Oliveira, J. E. and N. Souza. 1967. Metabolic studies with a corn and soya mixture
for infant feeding. Arch. Latinoam. Nut. 17: 197.

5. Campos, Jr., J. and J. E. Dutra de Oliveira. 1972. AbsorgBo de metionina pelo feyao e
melhqria do seu valor nutritivo. III. Reuniao de SLAN, Guatemala.

6. Moraes e Santos, T. and J. E. Dutra de Oliveira. 1972. Valor nutritivo de fravoes
proteicas isoladas do ferjao. Arch. Latinoam. Nut. 22: 547.


Luis G. Elfas
Ricardo Bressani
Marina Flores


The leguminosae comprise approximately 600 genera with around 13,000
species; however, out of this number only a few, about 20, are of'economic
importance as legume foods, and they are consumed either immature or dried by
humans. In Latin America the varieties recognized and accepted as edible food are
fewer. In Central America and Mexico, as well as Argentina, the most widely
consumed is Phaseolus vulgaris, in all of its variety of forms and colors. Although
in lower amounts other legume foods such as Phaseolus lunatus, Vigna sinensis, Cicer
arietinum, Lens esculenta and Cajanus cajan are also eaten in specific regions of this

Preference for one type of legume over the other is probably related to
availability in the area; in turn, availability is determined by environmental
conditions which favor higher yields of one over other legume toods. It is also possible
that factors not related to agronomic aspects are responsible for preferences, such as
dietary habits and cultural practices. Apart from these problems, it must be
recognized that a great part of this potential source of protein, which could help
improve the nutritional value of the diet consumed by the Latin American population,
has not been fully utilized. This is due notonly to the low production of this food,
but as well to lack of adequate storage conditions, which further limit its availability.

The purpose of this paper is to analyze some present and potential aspects
related to the storage and processing of legume foods in Latin America.


Obviously, it is necessary to know the availability of the raw material if
recommendations are to be made in order to improve storage conditions and
increase the possibilities for processing. Unfortunately, due to extensive gaps in crop
production statistics, no accurate statement can be made as to the production of

legume foods in Latin America. One of the reasons is that in most of the area legume
foods are grown in small plots, usually around the homestead, to supply the needs
of the family. Only that part of the production calculated as a surplus is sold in the
market, or when the need for money arises. Even though the figures have their
limitations, it is possible to draw some interesting observations from them.

The data published in the 1966 FAO Production Yearbook for the six continents
are shown in Table 1. As can be observed, the production of dry beans in Latin
America is only surpassed by the Far East. Yield per hectare is quite variable for the
same species, not only between regions, but also between species in the same region,
suggesting that some species are better adapted to environmental conditions than
others. Therefore, an increased production would be achieved through the selection
of species which are best adapted to prevailing environmental conditions in the

On the other hand, the variability of production and yield indicates also that
there is a definite potential in the developing countries for a substantial increase in
legume food production. It is also of interest to note that yields vary with the type
of pulse and with respect to region, being lower for Latin America, Africa and the
Far East. Such a situation could well be due to slow development of improved
varieties, poor agricultural practices and adverse environment. It is feasible to think
that the use of an appropriate technology would permit an increase in the production
of legume foods in Latin America. However, higher production requires the availability
of adequate facilities to handle the crop in terms of storage an'd processing.

Postharvest problems

The chemical and physical characteristics of the leguminous seeds suggest they
are one of the more stable foods. However, long periods of storage require some
technical measures to avoid detrimental effects on their quality for processing, on
their organoleptic and culinary characteristics and on their nutritive value.

Dry bean quality includes the characteristic of softening during reasonable
cooking time, uniformity in color and size of the seeds, absence of fissures, and
normal sanitary conditions (1).


Lack of adequate storage conditions appears to be one of the most important
technological problems, affecting indirectly the production and more directly the
availability of leguminous seeds. The problem can influence these aspects mainly in
two ways:

(1). The farmer has to sell the crop to intermediaries at a lower price, before
demand for the product arises, thus reducing economic incentive.

(2). The total availability is affected by the physical and organoleptic changes
which occur in the seeds, due to inadequate conditions of storage, hardening of the
Shells being the effect most often observed.

Table'1. 'Production of dried pulses, by continent, in 1966

1965 Dry Dry Dry Chick Lentils Pigeon Cow- Vetch Lupines Other
beans peas broad peas peas peas pulses

Europe Area 4009 484 715 391 109 --- 13 314 225 357
Prod. 863 722 841 162 67 12 250 257 204
Yield 2.2 14.9 11.8 4.1 6.1 --- 9.2 8.0 11.4 5.7
-------------------------- -------------------------- ------------------------------------ --
North Area 645 112 -- --- --- 41 --
America Prod. 805 219 --- -- --- 24 ----
Yield 12.5 19.6 --- --- -- 5.9 -- -
-------------------------------------------------------------------- ---------------------
Latin Area 6293 151 297 132 64 23 --- -- 4 31
America Prod. 3776 120 188 120 40 15 --- -- 6 25
Yield 6.0 7.9 6.3 9.1 6.3 6.5 --- ---- 15.0 8.1
-------------------------------------- 7--------------------------------------------------- --
Near Area 190 13 248 247 307, --- 13 325 7 209
East Prod. 207 12 432 209 281 --- 13 298 12 227
Yield 10.9 9.2 17.4 8.5 9.2 --- 10.0 9.2 17.1 10.4

Far Area 7560 1146 16 10256 973. 2584 47 --- --- 4199
East Prod. 2315 946 17 6546 473 1915 27 --- -- 1995
Yield 3.1 8.3 10.6 6.4 4.9 7.4 5.7 --- --- 4.8
7 ----------------------------------------------------------------------------
Africa Area 1233 463 333 400 207 127 2504 21 226 1654
Prod. 607 345 295 240 122 49 1083 11 56 822
Yield 4.9 7.5 8.9 6.0 5.9 3.9 4.3 5.2 2.5 5.0

Area: 1,000 hectares.
Production: 1,000 metric tons.
Yield: 100 kg/hectare.
Ref. Taken from: FAO Production Yearbook (1966 b).

According to results of several studies carried out to establish optimum conditions
to maintain dry bean quality, the main factors involved are moisture content of the
seeds, environmental temperature, relative humidity and period of storage (2, 3, 4, 5).
Although there are no specific investigations studying these four variables
simultaneously, the results so far obtained indicate that these conditions are closely

Physical changes.

The most evident physical deterioration in quality through inadequate storage
conditions is the hardening of the shells. This effect is generally evaluated by the
time required for the beans to soften during cooking. Figure 1 shows the effect of
temperature, moisture content of seeds and period of storage on the cooking time of
a variety of Phaseolus vulgaris. By increasing the moisture, temperature and period
of storage, the cooking time required was increased significantly. These results also
indicate that a moisture content in the seeds-of less than 13 percent does not affect
the cooking time, regardless of the temperature and period of storage. Other studies
have confirmed the importance of the moisture content in keeping the quality of
dry beans during storage (3), indicating a high positive correlation between moisture
content in the seeds and cooking time.

It is also known that these conditions depend not only on temperature but also
on the relative humidity of the environment. Studies on the hygroscopic equilibria
of beans stored at different relative humidities (6) are of interest. Figure 2 shows
the results obtained with a variety of beans with an initial moisture content of 11.4
percent, stored at 250C in relative humidities ranging from 11 to 75 percent.

It was not possible to obtain equilibrium moisture values for relative humidities
between 80 and 98 percent, due to the development of mold growth on the seed.
Using this same procedure, different varieties were studied, and it was found that
there were no significant varietal differences in equilibrium moisture values.
However, differences were found in the change of moisture content when beans
were stored at high humidities. From these results it was possible to establish a
relationship between the equilibrium moisture values and the environmental relative
humidity, as shown in Figure 3.

These studies to find the adequate storage conditions should be carried out with
the varieties most often consumed in our countries.

A longer cooking time due to varietal differences or inadequate conditions of
storage constitutes a problem to the housewife because of fuel costs, and at the
industrial level also, since food processors standardize processing methods.

Although less appreciated, another important problem is biodeterioration of the
seeds, due to the attack of insects, fungi and rodents. In this case also, proper
conditions of storage and appropriate handling and cleaning of the material
contribute to decrease serious wastage of a food which is at present in shortage.

Changes in the chemical and organoleptic properties

Besides the observed changes in texture, beans can also be affected during storage
in their organoleptic properties.

% H=16.0

H 13.9

SH 12.2%

30 H = 10.3
0 %5H= 8.2


-- 10

S50 -
55 12.80C % H = 16%

30 % H =13.9

S% H = 17.2
30 - ----------_----------- _. %_"H ,,.0%_

20 -% H = 13.9
% H = 12.2


6 12 18 24
Period of storage (months)
Taken from: Purr, H. K., Samuel Kon and H. J. Morris. Food Tech. 22: 336, 1968. Incap 73-98

Figure 1. Cooking time of Pinto Beans stored at different humidities and

18 /

HR = 75.3%


HR 64.4%

HR = 53.3%

10 HR r 42.8%

o, HR = 33.0%

HR 33.4%

6 HR 11%


Michelite beans (Phoseolus vulgoris)
stored at 250C

2 -Initial moisture content = 11.40.
M = Mold

0 l, iSIl i s
2 4 6 8 10 12 14 16 18 20 22 24
Period of storage (weeks)

Taken from: Weston, W. J. and J. 4. Morris. Food Tech. 8: 353, 1954. Incop 73-99

Figure 2. Rates of approach to moisture equilibrium at various relative humidities.

/ i
18" /



M = Mold become visible



0 10 20 30 40 50 60 70 80
Percent relative humidity

Token from; Weston, W. J. and J. H. Morris. Food Tech., 8: 353, 1954.
Incap 73-96

Figure 3. Relation of equilibrium moisture content to storage relative humidity at 250C.
Michelite beans (Phaseolus vulgaris).

7 ,'o Control samples
n A o ~ I stored at -23.30C

* Variety .
U Light Red Kidney
o Great Northern
o 4
Sa Michelite \
g Red Mexican
o a Pinto


5 10 15
Percent moisture

Taken from: Morris, H. J. and Wood, E. R. Food Tech. 10: 225, 1956.
Incop 73-101

Figure 4. Organoleptic evaluation vs. moisture content of dry beans stored 2 years at 250C.


Figure 4 shows the results when six varieties of beans with different moisture
contents were stored for two years at 250C. These data indicate that beans with a
moisture content higher than 10 percent, developed off-flavor, whereas beans stored
with a moisture content below 10 percent kept their quality for two years. These
organoleptic changes are due to the deterioration of the lipidic fraction of the seeds,
as is illustrated in Figure 5, which shows an increment in the acid value of this
fraction for beans with a moisture content higher than 10 percent. It is also of
interest that the fat content of pulses represents a relatively small percentage of
their overall composition, varying from 1 'to 6 percent depending on the species (7).

However, it has been found that a high percentage of the lipid content is of
unsaturated fatty acids, consisting mainly of palmitic, linoleic and linolenic acids,
together with smaller amounts of stearic and oleic acids (8, 9, 10, 11, 12).
Development of a rancid off-flavor during storage, therefore could well be due to the
action of the enzyme lipoxidase present in beans on the unsaturated fatty acids (9).
It is also possible that oxidation and polymerization of the lipids cause changes in
water permeability which in turn affect cooking time (9). The main factor affecting
the texture of the seeds, that is, the moisture content, is also responsible for the
deterioration observed in their organoleptic properties. Figure 6 illustrates the effect
of moisture content on the lipid acid values of a variety of Phaseolus vulgaris. The
sample with 16 percent moisture, at six months of storage, gave a relatively high
acid value as compared to the initial values, and increased significantly with the
storage period. On the other hand, the sample with a moisture content of 5 percent
was stable during 24 months of storage. Panel testing carried out on the same
material showed a positive correlation between the lipid acid values and acceptability

Changes in nutritional value

There is little information in the literature related to the effect of storage on the
nutritive value of bean protein. Some investigators (1), however, have suggested that
the factors affecting the physical-chemical, organoleptic and culinary characteristics
of legume foods could also alter its nutritional quality due to the longer time required
for cooking (3, 13).

Specific studies related to the nutritive value of soybean during storage have been
reported by some investigators (14, 15) using in vitro techniques. These results
indicated that protein solubility in salt solutions, as well as the enzymatic
digestibility, decreased during storage. Table 2 shows the effect of storage on the
biological value and the digestibility of soybean protein. Biological value decreased
during the period of storage for the raw whole beans as well as for ground
autoclaved seeds. It is also of interest that the reduction in protein quality was not
observed until 12 months of storage for autoclaved beans. Storage decreased
protein digestibility only for raw whole beans.

Further work on this problem carried out by Mitchell and Beadles (16), indicates
that the higher stability of autoclaved beans as compared to the raw is probably due
to the lack in the processed beans of conditions which permit enzymatic reactions
to take place. These enzymes are involved in respiration processes in the embryo,
which accounts for 92 percent of the total weight of the seed. According to the
authors this factor could also explain that the nutritive value of cereal grains stored
under these conditions is not appreciably altered by seed respiration since the embryo
or germ in these seeds represents only 9 to 10 percent of their total weight.

Table 2. The effect of storage on the true digestibility and B. V. of
whole soybean and soybean ground and autoclaved

Treatment True Biological
digestibility value

Raw soybean 84 72
Stored for 8.5 months
at 26 27 C (78-80 F) 78 63
Stored for 12 months at
26 27C (78-800 F) 79 66

Ground, autoclaved
and stored for 8.5 months 85 73
Ground, autoclaved and
stored for 12 months 84 68

Taken from: Mitchell, H. H. (quoted in Adv. Food Res. 4:269, 1953)
Ind. Enq. Chem. Anal. Ed., 16: 696, 1944.

Adverse conditions of storage can also affect the nutritive quality of bean proteins,
through a reduction of the availability of some amino acids, as reported for other
foods (17, 18, 19, 20, 21, 22).


Measures to increase the production as well as to improve storage conditions of
legume seeds are one of the most important aspects for the solution of the
problems faced by this crop. An additional aspect is that technological processes are
required to take care of increased availability. It is also very important to find new
ways of utilizing the product.

Industrialization of beans could, in fact, be an indirect way to increase their
cultivation through a more stable economic incentive, and could be a guarantee in
the utilization of the crop. In addition it would permit selection of varieties needed
by the industry and consequently stimulate the use of improved agricultural practices.

The processed product would have, furthermore, the advantages of a higher
stability, constant availability through the year, more uniformity, and easier
preparation, and could also be used as a vehicle for other nutrients. From the
industrial point of view, the main problem is economic, since processing involves an
increase in the final cost of the product. This aspect becomes more important in the
case of beans, since this food is a basic ingredient in the diet of most Latin American

Types of processing

The types of processing must be developed according to the dietary habits of the
population and also to the forms in which the food is consumed. This does not mean
that other types of products could not be processed, but in the beginning it would
be easier to introduce preparations that are part of the normal diet.

Light Red Kidney O
o Great Northern
o Michelite
A Large Lima
Red Mexican A
A Pinto A

o @

t't I Control

5 10 15
Percent moisture
Incop 73-100
Token from: Morris, H. J. and Wood, E, R., Food Tech., 10: 225, 1956

Figure 5. Acid values of lipid fraction in 6 varieties of dry beans of different moisture
content stored 2 years at 25oC.

1H 10.5
(Stored at -23.3oC)

Period of storage (months)
Token from: Morris, H. J. and Wood, F. R. Food Tech. 10: 225, 1956.


Incop 73.97

Figure 6. Effect of moisture content on the lipid acid values of a variety ofMichelite beans
(Phaseolus vulgais) stored at 250C.


The food technologist must also have in mind the housewife's convenience in
preparing the product. In the case of legume foods, the types of products that can
be processed are (1) pre-cooked, dehydrated whole beans; (2) pre-cooked bean flour;
(3) canned bean (whole); (4) canned beans (fried). Each one of these processes will
be analyzed as to advantages and problems.

Pre-cooked, Dehydrated Whole Beans

Continuous advances in food technology have made possible development of
different processes for the preparation of pre-cooked, dehydrated whole beans. A
great deal of research has been done to reduce the cooking time of beans, and at the
same time to avoid adverse changes in the physical characteristics of the final
product. Figure 7 shows an outline of some methods proposed and utilized in the
preparation of this product.

In general terms, it consists of soaking the beans in water, steam-cooking,
followed by dehydration (23). A blanching step has been recommended by some
investigators (24, 25), indicating that this additional treatment offers the advantages
of ensuring complete hydration, and destroying lipoxidase activity prior to soaking,
improving in this way the stability of the processed product during storage.

Freezing before or after cooking as well as dipping in a sugar solution is carried
out to avoid "butterflying", a characteristic represented by the development of
fissures which appear during drying of cooked beans. The cooking time required to
soften the final product varies according to the process employed and the variety of
beans utilized, as well as the previous conditions of storage. In this case, the final
product is ready for consumption after rehydration and a cooking time of 5 to 10

The process shown at the right of Figure 7 involves hydration of the dry beans by
soaking in water, pre-cooking in steam, cooking and dehydrating. The processed
beans are ready for consumption after covering them with hot water, followed by
boiling for 30 minutes. This process is claimed to have advantages in terms of cost
and of product quality.

Other processes (26, 27) that have been described, ensure not only the physical
appearance of the product, but also the stability of its nutritional quality.

In one of these processes (Figure 8), the main feature is that the cooking step is
omitted. In this case, beans are subjected to an intermittent vacuum treatment for
30 to 60 minutes in a solution of inorganic salts, which facilitates hydration in the
soaking step which is carried out later, using this same solution. The material is then
rinsed and dried. Cooking time of the processed beans varies between 25 to 30
minutes.-With little modifications, this process can also be used to prepare pre-
cooked frozen beans. In this case, cooking time of the final product varies between
10 to 20 minutes.

In the other process (Figure 9) beans are coated with sucrose instead of dextrose
to avoid the development of fissures during drying, as well as to maintain the
nutritive value. This is possible since there is no Maillard reaction (29, 30, 31) which
occurs when a reducing sugar, as for example dextrose, is used (32). This reaction
is known to decrease the nutritive value of foods, due to the interaction of
carbohydrates with amino acids, giving as result a decrease in the physiological
availability of these nutrients.

I lonchirng

- ^ Freezing

- Freezing

Feldberg y col.
Food Technol. 10 523, 1956.

Dorsey y col.
Food Technol. 15 13, 1961.

Stelnkrous y col
Food Technol. 18 1945, 1964.

Incop 73-92

Figure 7. Processes used in the preparation of pre-cooked, dehydrated whole beans.

Rockland, L. B., and Metzler, E.
Food Technol. 21: 344, 1967.

Rockland y col.
J. Food Sci. 34: 411, 1969.

Incap 73-94

Figure 8. Processes used in the preparation of pre-cooked, dehydrated whole beans.


La Belle y col. (1969). Ninth Dry Bean
Research. Conference at Forth Collins,
Colorado, August 13-15, 1968. (ARS
Incap 73-93

Figure 9. Processes used in the preparation of pre-cooked, dehydrated whole beans.










For the housewife's convenience, industry is manufacturing different types of food products from
legume grains.





Damage of beans (right) occurred during drying in comparison with pre-cooked beans, processed
adequately (left).


_ _

Close-up of damaged pre-cooked beans.

-. ___ J~:3mor



Partial loss in color in bean flour occurs generally when black beans are used.



i '


Pre-cooked Bean Flour

The technology used in the preparation of pre-cooked bean flour (33, 34) is very
similar to the processes previously described (See Figure 10). The material is
subjected to soaking, cooking and dehydration, followed by grinding. The final
product is ready for consumption after cooking for 10 to 15 minutes.

As in the previous process, the main objective is to obtain a quick-cooking product
with minimum deterioration of the organoleptic and nutritional properties of the
original material.

Two problems have been found in relation to the physical characteristics of the
final product: the final texture of the preparation and a discoloration of the flour.
Partial loss in color is mainly observed when black beans are used.

Apparently this change can be controlled by processing conditions during
cooking. Cooking in water seems to facilitate solubility of the pigments located in
the seed coat, which further penetrates the cotyledons, resulting in a darker flour
color. A discoloration of the flour is observed when the cooking step is carried out
without the addition of water. This is a very important aspect from the viewpoint
of the consumer, since a good quality of black bean soup is associated with its
darker color. Coarse texture of the flour is due to the presence of dried particles of
the seed coat, which is not completely pulverized. Care should be taken in the
grinding step to obtain a more homogeneous product, since eliminating the seed
coat makes the process more expensive.

Several studies have been made of the effect of this process on the nutritive value
of the bean proteins (13, 34, 35, 36). The results shown in Table 3 demonstrate that
a cooking time beyond 30 minutes at 1210C under 16 lbs pressure, without a previous
soaking, decreases the nutritive value of the proteins. This reduction is due, in part,
to a lower availability of lysine, one of the essential amino acids (13). The combined
effect of different periods of soaking and cooking time on protein quality is
illustrated in Figure 11. The data show that optimum cooking time for the samples
without soaking varies from 20 to 30 minutes. On the other hand, the soaked
samples showed a reduction in the nutritive value when the cooking time was
higher than 10 minutes.

Statistical analysis showed significant differences between the samples subjected
to 16 and 24 hours of soaking and those cooked for 20 and 30 minutes (37).
Furthermore, the conditions of soaking, cooking and grinding must be controlled in
order to obtain an acceptable product, from the organoleptic and nutritional point
of view.

Pre-cooked Canned Beans

The preparation of pre-cooked canned beans differs from the process previously
discussed in at least two aspects. First, beans are generally cooked in the can, and
second, in some products the legume food is mixed with other ingredients, such as
meat, tomato sauce, and other condiments. The simplest product is prepared with
beans in brine.
To obtain an acceptable texture in the final product, it is important to use beans
with a normal cooking time, since it has been reported that sometimes canners find
that the heat process required to sterilize canned beans is not sufficient to make
them tender (38).

Table 3. The effect of cooking on the protein quality of beans

Cooking Weight Protein
time b gain efficiency
minutes g/28/days ratio

0 Oa 0

10 75 1.31

20 72 1.35
30 76 1.29
40 59 1.20
60 35 0.89

90 37 0.92

120 37 0.88

150 29 0.78
180 24 0.63

a. All animals died.
b. Cooked in autoclave at 1210C and 16 lbs pressure.

In some cases canning has been found to affect protein quality significantly (39).
For example, in the preparation of canned beans with sauces, sugars are generally
added, which can react with bean proteins under the high temperature processing
conditions, causing non-enzymatic browning reaction to take place (29). This
reaction is desirable from the organoleptic point of view, giving a product with a
characteristic flavor, known as "baked beans". However, the nutritive value is
drastically affected (39, 40, 41, 42) if a reducing sugar, like glucose, is-used.

Table 4 shows the effect of adding glucose and sucrose on the protein quality of
canned beans. Canned beans, cooked in water for 70 minutes, showed a decrease in
weight gain and in protein efficiency ratio, indicating a reduction of nutritive value.
The addition of sucrose to the input solution, resulted in a slight decrease of these
two parameters, whereas the presence of glucose alone in the canned product
reduced significantly the weight gain as well as the protein efficiency ratio. The
simultaneous addition of sucrose and dextrose to the input solution, did not
significantly affect the protein quality as compared with the addition of glucose

Excessive cooking time affects not only the protein quality, but also the
vitamin content of the product. Lantz et al (43) have shown an increased destruction
of thiamine in prolonged cooking.

Stability of the processed products

The processes to which beans are subjected no doubt help increase the chemical
stability and the organoleptic, cooking and nutritional characteristics of the raw




Pressure cooker 15-30 min.
Cloy pot 2-5 hrs.

Whole beans Brot


(fat, gorlich, onion, others)

Soft puree
fried beans


Fried beans



Retort 1210C
30 min.




- Rehydration

Incop 73-102

Figure 10. Process for the preparation of pre-cooked bean flour.


(Growing rats)


m 30




* 0 hrs soak

A 8 hrs soak

O 16 hrs soak

O 24 hrs soak

0 10 20 3
Cooking time (min)

Dry bean samples processed after 4 months of storage at ambient.

Figure 11. Relationship between average weight gain and PER with cooking time of bean
samples (dry bean samples processed after 4 months of storage at ambient) subjected to
various soaking times (Growing rats).

Incop 73-110

Table 4. Protein quality of canned beans

Samples of canned beans Average weight Protein
gain, g/53 days efficiency

1. Cooked with water* (20 min) 72 1.53
2. Cooked with water (70 min) 44 1.06
3. Cooked in 10% sucrose solution 40 1.09

4. Cooked in 10 glucose solution 4 0.16

5. Cooked in solution of
8 % sucrose and 2 % glucose 26 0.78
6. Control: casein-lactoalbumin
(5:1) 158 3.64

*Cooking temperature: 1210C.
Taken from: Powrie, W. D. and E. Lamberts. Food Technol. 18: 111, 1964.

material. However, storage time and conditions, as well as the type of packaging
will influence to a larger extent the keeping qualities of the product. When pre-cooked
and dehydrated whole beans, for example, were packaged in plastic bags (25)
at room temperature, there was no sign of damage after one year of storage. Similar
samples stored at 500C and 50 percent relative humidity developed an unpleasant
odor after two months. It has also been found that a higher water content in the
product is conductive to lesser stability of its physical and organoleptic characteristics.

Similar studies have been carried out on stability of pre-cooked bean flour.
Recently, Del Busto et al (50) found that storage temperature and type of packaging
affected the stability of this product (Figure 12). After 15 months of storage, the
flour packed in paper or in polyethylene bags showed an increase in the free fatty
acid content, as well as in the water content. Similar results were obtained with
storage at 50C although the increase of free fatty acids was lower than in the previous
case (Figure 13). These and other results (51, 52) indicate that the final water
content in the processed food is a very important factor in retaining the organoleptic
qualities of the product. In this regard the addition of antioxidants is an adequate
solution to avoid the damage due to deterioration of the lipidic fraction.

Loss of the original color and alterations in texture and odor have been the main
problems found during prolonged storage of canned beans. This physical and
organoleptic damage is due to an interaction between traces of minerals with the
organic constituents of the seed, taking place during the autoclaving and later on
during the storage period. The addition of chemicals during the soaking process
often contributes to the keeping of characteristics demanded by the consumer (53).
Obviously, these aspects are very important and should be taken into consideration
when dealing with the different climatic conditions in Latin America.

Technical and nutritional problems

The technological and nutritional problems inherent to each of the products
described can, in general, be solved by means of adequate processing techniques.

Storage: Ambient temperature

Paper bag

Free fatty acids*

Paper bag

Moisture' --
Plastic bag

mg KOH 100 g sample
% moisture

Time, months

Incop 73-108

Figure 12. Effect of storage on precooked bean flour quality.

Storoge temperature: 50C

Free fatty acids*

Poper bag I

..-------------- /

0 3 6 9 12 15 18
Time, months

* mg KOH 100 g sample
** % moisture
Incap 73-107

Figure 13. Effect of storage on precooked bean flour quality.





A ~.:

* I-^^

Pre-cooked gandul flour, pre-cooked cowpea flour, pre-cooked black bean flour and mixture of
black bean and cowpea flours. Note similar appearance of products.





Pre-cooked bean flour and canned fried beans are two products that have been in the market of
Guatemala since 1971.



. ,

Whole cooked beans with rice is a typical dish in several Latin American countries.



Pre-cooked flour of legumes can be used to prepare soups of different type and flavor.


This technology, however, is used to a limited extent by the food industry, in the
Latin American countries, mainly because of the unavailability of the raw material,
and the lack. of acceptability of the product by the consumer for economic reasons.

The food industry needs perforce a constant availability of raw materials. In the
case of beans, the problem is more complicated since beans are a basic food in most
Latin American countries, and thus the direct demand of the population competes
with industrial demands.

The problem could be obviated, at least in part, by increasing production or by
using other legume grains less consumed than beans but capable of being used in
processed foods. As an example, it is possible to partially replace beans (P. vulgaris)
by other legumes in the production of pre-cooked black bean flour, without
'affecting the nutritional or organoleptic characteristics of the product. Table 5
summarizes results obtained in biological trials when black bean flour was
substituted by cowpea (Vigna sinensis). Substitution did not significantly alter
'protein quality as measured by weight gain of experimental animals and protein
efficiency ratios.

Another interesting aspect shown in this table is that as cowpea replaced black
bans, no.increase in the weight of the pancreas was observed. The increase of
pancreas weight, according to previous studies (44, 45, 46), is a reflection of the
presence or residues of heat-stable trypsin inhibitors present in some legumes.
Cowpea thus presents the added advantage of being free of trypsin inhibitors, and
some varieties have a superior protein quality to that of beans(Phaseolus vulgaris)

Combinations of black beans with other legumes such as pigeon pea (Cajanus
cajan) could also be used in order to make black beans more available, possibly
reducing the price of the product and developing interest in the production of new
legumes in Latin America.

As concerns acceptability of these products by our population, it has been said
that for several reasons, it would not be successful at present. We believe that the
industrial and economic change that has been taking place in our countries will allow
the consumption of these products by the majority of the population. In Guatemala,
.for example, at least two of these products pre-cooked bean flour and canned fried
beans have been in the market for the last two years, thus showing the feasibility
of processing and consumption of these products.

Advantages and uses

Advantages of a processed product, mentioned previously, are greater stability,
uniformity, and availability. Regarding beans, shorter cooking tire is an obvious
practical advantage to the housewife. The use of these products will, of course,
depend on the culinary preparations in each country. Pre-cooked and dehydrated
beans can be used in several cooking preparations, such as whole cooked beans,
beans and rice, salads and so forth.

Pre-cooked flour of legumes can be used mainly as soups of different type and'
flavor and other home preparations as shown in Figure 10. Besides, it cap be
combined with other foods in the preparation of thick soups of a high nutritive
value (49). Table 6 shows the composition and nutritive value of one of these
products developed by INCAP. The quality of the protein of the basal formula, as
evaluated by protein efficiency ratio, is quite high.


Table 5. Protein quality of different combinations between black
beans (Phaseolus vulgaris) and cowpea (Vigna sinensis)

Ingredientes 1 2 3 4 5 6 7 8

o0 Precooked cowpea flour, .% 33.00

Precooked black bean flour, -

Percentage distribution of
protein in the diet from cowpea 100

From black beans 0

Average weight gain, g 56

Protein Efficiency Ratio 1.69

Weight of pancreas, g 0.445

26.40 23.10 19.80 16.50

8.30 12.50 16.70 20.80

80 70

20 30

46 50

1.53 1.401

0.368 0.326

60 50

40 50

53 48

1.61 1.50

0.995 0.923





40 20

60 80

55 55

1.54 1.57

1.038 0.9657






Table 6. Composition and protein quality of soup base formula of high nutritive value

Ingredients in the basal formula

Precooked beans flour

Cereal flour (corn, rce)

Cottonseed flour

Torula yeast


Percentage of protein
in the diet,

Weight gain, g

Protein Efficiency Ratio









Soup Base formula

Base formula

Seasonings and
other ingredients







3 4

Above and below: physical appearance of pre-cooked flours of legumes and home made soups
prepared with these products.

^ I^ --------------





The quality of the raw material determines to a very large extent the quality of
the final product. Adequate storage conditions are of primary importance in
retaining bean quality for processing. The phenomenon known as hardening of the
seed is one of the most serious problems confronting the food industry, since
"hard" beans are not properly cooked during the time normally used in this step of

With the purpose of separating normal beans from "hard" ones, Bourne (54)
developed an interesting practical method based on the fact that seed size in a given
lot of beans follows a normal pattern of distribution, while "hard" beans are usually
found in the fraction comprising the smaller size. Rejection of 20 percent of beans
prior to soaking discards about 70 percent of "hard" beans. Likewise, during the
soaking process, normal beans absorb water and swell, while "hard" beans do not
swell and are, consequently, discarded with the smaller-size seeds. Selecting again
for size after soaking, "hard" beans can be practically eliminated, obtaining a better
final quality of raw material.

Storage-conditions can also determine the processing to which beans should be
subjected. It has been found, for example, that when recently harvested beans are
processed by the same technology used for beans that have been under storage, results
on the nutritive value are different (37), as can be observed inr Figure 14.

In this case, protein quality was damaged by cooking times longer than 10 minutes,
including those samples that were not previously soaked, which suggests a greater
swelling capacity of the recently harvestedbeans. This hypothesis was confirmed
(Figure 15), when the hydration coefficients of recently harvested beans, and
beans stored for four months under laboratory conditions, were compared. Beans
that had been stored did not, in 24 hours, reach the hydration level reached by the
recently harvested beans in 8 hours (37). These results could explain the greater
sensitivity of the fresh bean protein to the thermal treatment used during processing,
especially that of samples which were not subjected to soaking.

In some cases, bean quality can also determine the kind of processing which will
be more adequate from the practical and economic points of view. The seeds that
require a longer cooking time, for example, can preferentially be used for the
manufacture of precooked flours, thus utilizing a raw material which is unfit for
ordinary consumption or for other preparations.


The most pressing nutritional problem facing Latin America seems to be the
unavailability of legume seeds for human consumption, due mainly to agronomic,
economic, and technological factors.

Inadequate storage conditions contribute also to decreased human consumption
of these products, due to a deterioration of the cooking and organoleptic
characteristics of the seeds.

Industrialization of beans could help to partially solve the production problem,
through an incentive for increased agricultural technology, price stabilization,


* 0 hrs soak

A 0 hrs sook

O 16 hrs soak

3 24 hrs soak

10 20 30
Cooking time (min)


* 0 hrs soak

A 8 hrs sook

O 16 hrs sook

.r- 24 hrs soak

Cooking time (min)

Dry bean samples processed soon after harvest.

Incoo 73-111

Figure 14. Relationship between average weight gain of rats and cooking times of
bean samples subjected to various water soaking times.'

1 1 I


0 Dry bean samples processed after harvest

A Dry bean sample processed ofter 4 month
of storage at ambient

Soaking time (hrs)

Incop 73-112

Figure 1'S. Relationship between soaking time and hydration coefficient of bean



greater availability throughout the year of these products, and production of a
variety of processed foods aimed at the convenience of the housewife.

Since beans are a basic food in most Latin American countries and considering
their potential as a protein source, their increased consumption would contribute
to the improvement of the nutritional status of these populations.


Studies are needed on the storage of the most common varieties of beans
consumed in Latin American countries, in order to establish the adequate conditions
that will guarantee the preservation of the crop up to the time of purchase by the
consumer. These findings would lead to the construction of adequate silos, thus
guaranteeing the farmer the economic incentive of his crop.

Since quality of raw materials is of vital importance to the food industry,
improved legume varieties should be selected that will fulfill the quality standards
needed for the production of processed foods that can compete advantageously
with other products in the food industry market.

Another desirable measure would be to increase the production of other high-
yielding legume grains that are not normally consumed in these countries and.
which are easy to cultivate. The selection of varieties with the same seed shape and
color as normally consumed by the different regions should not be overlooked since
they could be used in processed foods as a partial substitute for those legume grains
which are already accepted, with consequent increased availability of the latter.

It is possible that through research and through conferences like the present,
beans will finally achieve the preeminent place they deserve in the field of food
technology since, through the years, they have played and continue to play a
significant role in the cultural and dietary pattern of the Latin American countries.


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Marina Flores
Ricardo Bressani
Luis G. Elias

Discussant: Francis C. Byrnes


Anthropologists and sociologists have been the first investigators to provide
information on food habits from regions of historical interest in civilizations that
have disappeared, or native groups living in primitive conditions. Little is known
about food habits elsewhere because research studies have been very scarce.

On the other hand, nutritionists have been studying the quantitative consumption
or availability of food in each country without paying too much attention to food
habits. Nevertheless, the developing countries are those in need of such
information. In some, customs and food habits are known but unfortunately
sociologists and anthropologists do not give the origin but only the prevalence of
these customs without data on the reasons behind them. Therefore, some
nutritionists, as they gather data on quantitative intake also take the opportunity to
collect information to explain food habits. This is the case in Central America (1-8)
where the characteristics of the diets are well known in the different population
groups, and the reasons for the dietary habits in those food patterns.

These studies were first carried out through dietary surveys which covered
seven days of almost living with the family (9) to observe the handling, preparation
and distribution of foods within the family. In Guatemala, unique in this regard,
the anthropologist Antonio Goubaud Carrera (10) studied extensively all social
aspects and especially food habits among rural communities.

Later, the dietary studies in Central America have continued in.a more
specialized way, as measuring the food consumption of preschool children (11, 12).
Small children represent one of the most vulnerable groups in regard to nutritional
status of the population of Central America and Panama.


Nature offers human beings an enormous variety of foodstuffs. Men usually
select them according to the quantity in which they are produced and give preference
to those that satisfy their basic needs. The main cultures and civilizations have
flourished in areas where man's efforts were rewarded by abundance of a certain
indigenous cereal.

Rice, wheat and maize have represented the source of life for the civilizations
of the Far East, the Mediterranean (Egypt and Rome) and America,'respectively,
during the development of their societies. The opening of routes across the world
brought those grains to the rest of the world, where they combined with other
products and formed special dietary designs called food patterns.

In some areas of the world, the majority of people enjoy plentiful food sources,
while in others low production limits food availability drastically, and only a minority
satisfies its needs. The amounts in which different items are consumed by people in
each area, and the customary treatment given to them, determine the levels reached
by calorie and nutrient intake in every population group.


Differences in types of foods and combinations in which they are consumed
have been determined by several ecological factors, defined below.

Geographical Location

The territory where man happens to live will lead him to select the staple, as
well as other food products, with which to build his diet. In the highlands or near
the sea, close to the rivers or lakes, in the tropical or temperate zones, land and water
will offer him different foods.

In general, most cereals such as wheat and maize, and legume grains, such as
beans or chickpeas, grow better in the highlands and temperate climates, while some
root crops, such as sweet potatoes or yam, and oily seeds, as sesame or cotton, are
native to warm lowlands. Sea shores shaded by palm trees provide foods rich in
protein and fats; in addition, a variety of marine products may be available.

Extensive grassy plains where cattle or other domesticated animals can be fed
provide their inhabitants with meat and milk. Thus, great differences in food patterns
may exist not only between countries, but also within each country.

Cultural Factors

Throughout the centuries, cultures have developed around an area's principal
indigenous foods. Man learned to cultivate and domesticate the necessary plants
and animals. After many generations, he inherited special technologies for preparing
those products. Each society disseminated its own culture, so foods which originated
in one place appeared in different areas also, following the expanding civilization.
Optimum climatic and soil conditions found in differing areas have favored the