Title: Research highlights
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00071929/00004
 Material Information
Title: Research highlights
Uniform Title: Research highlights (East Lansing, Mich.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Bean/Cowpea Collaborative Research Support Program
Publisher: Michigan State University Bean/Cowpea CRSP
Place of Publication: East Lansing
Publication Date: 1984-
Subject: Beans -- Research -- Periodicals -- Africa   ( lcsh )
Beans -- Research -- Periodicals -- Latin America   ( lcsh )
Cowpea -- Research -- Periodicals -- Africa   ( lcsh )
Cowpea -- Research -- Periodicals -- Latin America   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
Statement of Responsibility: Michigan State University Bean/Cowpea CRSP.
Dates or Sequential Designation: Vol. 1, no. 1 (1984)-
General Note: Title from caption.
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Bibliographic ID: UF00071929
Volume ID: VID00004
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 13864898

Full Text

Michigan State University Bean/Cowpea CRSP

Vol. I No. 4 1984

Ardeshir Ghaderi, Editor

Improving Food Accessibility
Through Village-Level Production
of Cowpea Meal
Nigeria/University of Georgia/McWatters

The cowpea (Vigna unguiculata) is proba-
bly the most important food legume in West
Africa, with more than 90% of the world
crop being produced in this region of the
world. The contribution of cowpeas to the
nutritional status of West Africans is dispro-
portionally large since they are consumed
locally rather than exported, contain a high
concentration (about 25%) of good quality
protein, and are highly favored by the
population. Cowpeas are used in West Af-
rica much as in the United States, as a fresh
vegetable and as a rehydrated palatable
cooked dry bean. In addition, cowpea paste
is the principal ingredient in several popular
dishes which are cooked by steaming or
deep-fat frying. Consumers prefer a light-
colored paste free of black specks and,
therefore, employ a rather labor-intensive
decorticating process to remove the seed
coats and hilum, "black eyes," from cowpea
cotyledons. This process involves soaking
dry seeds in water to loosen the seed coat,
decorticating by either manual rubbing or
stirring the wetted peas in a mortar and
floating off the seed coats in water, and
grinding to paste either on a stone, in a
mortar, or in an electric blender if available.
These time-consuming and laborious tasks
associated with preparing cowpeas for food
are a major constraint limiting their wider
Efforts to devise mechanical means for
removing the seed coat from dry cowpeas
have been successful, and equipment to de-

corticate peas by a dry, abrasive process is in
use on a limited scale in Nigeria. However,
yields of completely decorticated peas ob-
tained with this equipment are low because
tightly-adhering seed coats, not easily
loosened during the dry decortication pro-
cess, require extensive milling. Flour-like
products milled from decorticated cowpeas
are available in some local markets in
Nigeria but have not been widely accepted
by consumers because of their poor perfor-
mance in preparation of traditional foods.
A major focus of the collaborative re-
search project between the Unitersity of
Georgia and the University of Nigeria at
Nsukka has been the development of
technologies to improve the ease and effi-
ciency of seed coat removal. A simple, low-
cost pretreatment process has been devised
to loosen the cowpea seed coat. It involves
dipping cowpeas in room temperature
water, draining, then drying at 500C to a
moisture content of 5-7%. Cowpeas tem-
pered in this manner have loose, brittle seed
coats which are easily removed and sepa-
rated from the cotyledon. Although high
temperature drying (80-120C) is more rapid
than at 50C, adverse quality changes occur
including decreases in protein solubility,
water-holding capacity, and swelling capac-
ity, reduced rate of water absorption, and
development of an undesirable brown color.
Loosened seed coats may be removed
mechanically by means of the polishing sec-
tion of the Engelberg rice mill. This device

Funded through USAID/BIFAD Grant No. AID/DSAN-XII-G-0261

consists of an inner shafted, horizontal
wooden drum which rotates inside an outer,
stationary perforated steel cylinder. Numer-
ous short (4-inch) leather strips are attached
to the inner rotor which overlap and flail
freely against the outer cylinder. Cowpeas
are abrasively decorticated when the seeds
pass between the two cylinders and are pro-
pelled by the leather flails against the rough
walls of the stationary outer steel cylinder. A
large proportion of the seed coat and all of
hilum, "black eyes," are separated from the
cotyledons in one pass through the mill. The
discharge may be passed through the
polisher again or fed into an air aspiration
seed cleaner to separate the seed coats,
eyes, and fine particles from the split cotyle-
dons. The Engelberg mill is considered to be
ideal for use in a village industry because it
is simple to use, and over 4,000 are already
established, although underutilized, in rural
rice mills throughout Nigeria.

te 1: Technician at University of Georgia dumping
decorticated cowpeas from rollover dehuller.
Photo: McWatters

Following decortication and cleaning, peas
may be milled to produce meal or flour.
Since grinding the decorticated cowpeas is
another time-consuming process for the
consumer, the availability of a ready-to-use
meal or flour to which water could be added
to make paste should facilitate cowpea
usage. Another focus of this project has
been to determine the appropriate particle
size distribution for the milled product. A
number of mechanical devices (hammer
mills, stone mills) are readily available for
reducing peas and other grains to meal or
flour and can produce particles ranging in
size from very fine to very coarse. However,
cowpea meal having the greatest concentra-
tion of particles in the 50-200 mesh range
performs more satisfactorily in preparation
of traditional paste-based foods than very
fine or very coarse products. Following
milling, cowpea meal may be packaged in
single service (family) or bulk units for in-

Plate 2:
Plate 2:

Technician at University of Georgia passing
decorticated cowpeas through a seed cleaner
to separate seed coats and fine particles
from cotyledons. Photo: McWatters


stitutional use. Finished products with
physical and sensory characteristics very
similar to those made by the traditional pro-
cess have been prepared by mixing 60%
water with meal of appropriate particle size.
During the 5th year of this project,
cowpea meal processing will be initiated at
the village level for on-site evaluation. The
impact of village-scale processing and of the
resulting cowpea products on the sur-
rounding community will be monitored by
means of socio-cultural, socio-economic,
and nutritional studies.
Numerous supporting research activities
have been in progress throughout the pro-
ject. These include determination of effects
of various cooking methods on functional
and nutritional quality of cowpea meal, flow
characteristics of cowpea paste, functional
roles of cowpea starch and protein in foods
processed from cowpea paste, mycological
quality (mold) of cowpeas during long-term

storage, effect of vegetable oil treatments on
resistance to insect infestation and sensory
qualities of stored cowpeas, relationship of
water activity to moisture content sorptionn
isotherms) of cowpeas and cowpea flour
during storage, electronic monitoring of
cooking rates of cowpeas, and household
consumption profiles for cowpeas among
low-income families in villages in the Nsukka
area of Nigeria.
Storage and processing technologies de-
veloped in the project should provide read-
ily prepared forms of cowpeas in greater
quantities to consumers. Development and
implementation of technologies to improve
the utilization of cowpeas should contribute
to improved nutritional status and quality of
life for West Africans. Added benefits which
have become apparent as a result of project
activities are new applications for using
cowpeas which, though unfamiliar to the
American palate, have potential in this and
other developed countries.

Plate 3: Market stall in Nigeria with cowpea dough being fried into akara
balls. Photo: Barnes-McConnell

6 -,** y ^,,

Plate 4: Roving akara vendor's wares. Photo: Barnes-McConnell

For further information contact:
Bean/Cowpea CRSP
200 Center for International Programs
Michigan State University
East Lansing, Michigan 48824-1035

Telephone: (517) 355-4693
Telex: 810-251-0737

An international community of persons, institutions,
agencies and governments committed to collectively
strengthening health and nutrition in developing
countries by improving the availability
and utilization of beans and cowpeas

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