• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Table of Contents
 Introduction
 Methods
 Experimental
 Discussion
 Summary
 Literature cited






Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 444
Title: Levels of carotene and ascorbic acid in Florida-grown foods
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026712/00001
 Material Information
Title: Levels of carotene and ascorbic acid in Florida-grown foods
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 21 p. : ; 23 cm.
Language: English
Creator: French, R. B ( Rowland Barnes )
Abbott, O. D ( Ouida Davis ), b. 1892
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1948
 Subjects
Subject: Fruit -- Composition   ( lcsh )
Vegetables -- Composition   ( lcsh )
Carotenes   ( lcsh )
Vitamin C   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 20-21.
Statement of Responsibility: by R.B. French and O.D. Abbott.
General Note: Cover title.
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Florida Sea Grant technical series, the Florida Geological Survey series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00026712
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000925522
oclc - 18254076
notis - AEN6173

Table of Contents
    Front Cover
        Page 1
    Front Matter
        Page 2
        Page 3
    Table of Contents
        Page 4
    Introduction
        Page 5
    Methods
        Page 5
        Collection of samples
            Page 5
        Preparation of samples
            Page 6
        Carotene
            Page 6
        Ascorbic acid
            Page 7
    Experimental
        Page 8
        Average values
            Page 8
            Page 9
            Page 10
        Variety data
            Page 11
            Page 12
            Page 13
        Fertilization under field conditions
            Page 14
            Page 15
            Page 16
            Page 17
        Fertilization in pot cultures
            Page 18
    Discussion
        Page 19
    Summary
        Page 19
    Literature cited
        Page 20
        Page 21
Full Text



Bulletin 444


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
GAINESVILLE, FLORIDA









Levels of Carotene and Ascorbic

Acid in Florida-Grown Foods

By R. B. FRENCH and 0. D. ABBOTT









TECHNICAL BULLETIN









Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


May, 1948









BOARD OF CONTROL
J. Thos. Gurney, Chairman, Orlando
N. B. Jordan, Quincy
Thos. W. Bryant, Lakeland
J. Henson Markham, Jacksonville
Hollis Rinehart, Miami
W. F. Powers, Secretary, Tallahassee

EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President of the
University3
H. Harold Hume, D.Sc., Provost for Agr.3
Harold Mowry, M.S.A., Director
L. O. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield, M.S., Asst. Dir., Admin.
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Associate Editor"
Jefferson Thomas, Assistant Editors
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Managers
Geo. F. Baughman, M.A., Business Managers
Claranelle Alderman, Accountants

MAIN STATION, GAINESVILLE
AGRICULTURAL ENGINEERING

Frazier Rogers, M.S.A., Agr. Engineers
J. M. Johnson, B.S.A.E., Asso. Agr. Engineers
J. M. Myers, B.S., Asso. Agr. Engineer
R. E. Choate, B.S.A.E., Asst. Agr. Engineers
A. M. Pettis, B.S.A.E., Asst. Agr. Engineer3

AGRONOMY
W. E. Stokes, M.S., Agronomist'
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomist2
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
M. E. Paddick, Ph.D., Agronomist
S. C. Litzenberger, Ph.D., Associate
W. A. Carver, Ph.D., Associate
Fred A. Clark, B.S., Assistant

ANIMAL INDUSTRY
A. L. Shealy, D.V.M., An. Industrialist1
R. B. Becker, Ph.D., Dairy Husbandman'
E. L. Fonts, Ph.D., Dairy Technologists
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian'
L. E. Swanson, D.V.M., Parasitologist
N. R. Mehrhof, M.Agr., Poultry Husb.'
G. K. Davis, Ph.D., Animal Nutritionist
R. S. Glasscock, Ph.D., An. Husbandman'
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.'
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech."
Katherine Boney, B.S., Asst. Chem.
J. C. Driggers, B.S.A., Asst. Poultry Husb.'
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
S. John Folks, B.S.A., Asst. An. Husb.3
W. A. Krienke, M.S., Asso. in Dairy Mfs.
S. P. Marshall, Ph.D., Asso. Dairy Husb.'
C. F. Simpson, D.V.M., Asso. Veterinarian


ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agri. Economist1 '
Zach Savage, M.S.A., Associate'
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
R. E. L. Greene, Ph.D., Agri. Economist
H. W. Little, M.S., Assistant

Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr. Statistician'
J. B. Owens, B.S.A., Agr. Statistician'
J. F. Steffens, Jr., B.S.A., Agr. Statistician'

ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.1
R. B. French, Ph.D., Biochemist

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist'
H. E. Bratley, M.S.A., Assistant

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Truck Hort.
H. M. Reed, B.S., Chem., Veg. Proc.
Byron E. Janes, Ph.D., Asso. Hort.
R: A. Dennison, Ph.D., Asso. Hort.
R. K. Showalter, M.S., Asso. Hort.
Albert P. Lorz, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. D. Dickey, M.S.A., Asst. Hort.
Victor F. Nettles, M.S.A., Asst. Hort.5
F. S. Lagasse, Ph.D., Asso. Hort.2
L. H. Halsey, B.S.A., Asst. Hort.

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist1 '
Phares Decker, Ph.D., Asso. Plant Path.
Erdman West, M.S., Mycologist and Botanist
Lillian E. Arnold, M.S., Asst. Botanist

SOILS
F. B. Smith, Ph.D., Microbiologist'
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologists
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
C. E. Bell, Ph.D., Associate Chemist
R. A. Carrigan, B.S., Asso. Biochemist
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, Ph.D., Asso. Microbiologist
R. E. Caldwell, M.S.A., Asst. Chemists
J. B. Cromartie, B.S.A., Soil Surveyor
Ralph G. Leighty, B.S., Asso. Soil Surveyor
V. W. Cyzycki, B.S., Asst. Soil Surveyor


1 Head of Department.
2 In cooperation with U. S
Cooperative, other divisions, U. of F.
SIn Military Service.
On leave.










BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
W. H. Chapman, M.S., Asso. Agron.
R. C. Bond, M.S.A., Asso. Agronomist
L. G. Thompson, Ph.D., Soils Chemist
Frank S. Baker, Jr., B.S., Asst. An. Husb.
Kelvin Dorward, M.S., Entomologist

Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist

Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist

Mobile Unit, Wewahitchka
J. B. White, B.S.A., Associate Agronomist

Mobile Unit, DeFuniak Springs
R. L. Smith, M.S., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
J. T. Griffiths, Ph.D., Asso. Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Plant Pathologist5
R. K. Voorhees, M.S., Asso. Horticulturist
C. R. Stearns, Jr., B.S.A., Asso. Chemist
James K. Colehour, M.S., Asst. Chemist
T. W. Young, Ph.D., Asso. Horticulturist
J. W. Sites, M.S.A., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
J. A. Granger, B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Horticulturist
Francine Fisher, M.S.. Asst. P1. Path.
I. W. Wander, Ph.D., Soil Chemist
A. E. Willson, B.S.A., Asso. Biochemist
R. W. Jones. Asst. Plant Path.
J. W. Kesterson, M.S.. Asso. Chemist
C. W. Houston. Ph.D.. Asso. Chemist
R. N. Hendrickson, B.S., Asst. Chemist
E. H. Bitcover, M.A., Soils Chemist
L. C. Knorr, Ph.D., Asso. Histologist
Joe P. Barnett, B.S.A., Asst. Hort.
J. C. Bowers, B.S., Asst. Chemist
D. S. Prosser, Jr., B.S., Asst. Hort.
R. W. Olsen, B.S., Biochemist, Con. Res.
F. W. Wenzel, Jr., Ph.D., Supervisory Chem.
R. W. Jones, M.S.A., Asst. Plant Path.

EVERGLADES STA., BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
B. S. Clayton, B.S.C.E., Drainage Eng.s
J. W. Randolph, M.S., Agricultural Engineer
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. An. Husb.
T. C. Erwin, Assistant Chemist
Roy A. Bair, Ph.D., Agronomist
C. C. Seale, Asso. Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist


J. C. Hoffman, M.S., Asso. Hort.
C. B. Savage, M.S.A., Asst. Hort.
D. L. Stoddard, Ph.D., Asso. Plant Path.
W. A. Desnoyers, B.S., Asst. Hydrologist

SUB-TROPICAL STA., HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Director in
Charge
D. O. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robt. A. Conover, Ph.D., Asso. Plant Path.
R. W. Harkness, Ph.D., Asst. Chemist
Milton Cobin, B.S., Asso. Hort.

W. CENT. FLA. STA., BROOKSVILLE
C. D. Gordon, Ph.D., Geneticist in Charge2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Associate Agronomist
D. W. Jones, B.S., Asst. Soil Tech.
H. J. Fulford, B.S.A., Asst. An. Husb.

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Director in
Charge
A. Alfred Foster, Ph.D., Asso. PI. Path.
J. W. Wilson, Sc.D., Entomologist
Ben F. Whitner, Jr., B.S.A., Asst. Hort.

WEST FLORIDA STATION, MILTON
H. W. Lundy, B.S.A., Asso. Agronomist


FIELD STATIONS
Leesburg
G. K. Parris, Ph.D., Plant Path. in Charge

Plant City
A. N. Brooks, Ph.D., Plant Pathologist

Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist

Monticello
S. O. Hill, B.S., Asst. Entomologist' '
A. M. Phillips, B.S., Asso. Entomologist'

Bradenton
J. R. Beckenbach, Ph.D., Horticulturist in
Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
E. L. Spencer, Ph.D., Soils Chemist
Robert O. Magie, Ph.D., Gladioli Hort.
J. M. Walter, Ph.D., Plant Path.
Donald S. Burgis, M.S.A., Asst. Hort.

Lakeland
Warren O. Johnson, B.S., Meteorologist2

SHead of Department.
In cooperation with U. S.
Cooperative, other divisions, U. of F.
In Military Service.
SOn leave.

















CONTENTS
Page


INTRODUCTION ...... ..... ........................ .................... ........ ........ 5


M ETHODS ..... ...................................... .................... ... ...... 5


Collection of Samples ............................. ..... ... .. ................. 5


Preparation of Sam ples ........................ ........ .......... ..................... 6


Carotene ................................ ................................................. 6


Ascorbic Acid .....................................-........... ..- ........ 7


EXPERIMENTAL .......................................... ..................... 8


Average Values .............. .... .......................... 8


V variety D ata .............................................. ............................................ 11


Fertilization Under Field Conditions ........................ .............. 14


Fertilization in Pot Cultures ............................................... ................... 18


DISCUSSIN .................................................................................. 19


SUM MARY ................. ................... ........................... 19


LITERATURE CITED ....................................................... 20








Levels of Carotene and Ascorbic Acid in
Florida-Grown Foods

By R. B. FRENCH and 0. D. ABBOTT
It is generally recognized that intake of both carotene
provitaminn A) and ascorbic acid (vitamin C) in a large portion
of the population is far below optimum. In Florida during the
part of the year when citrus fruits are scarce and in sections
where these fruits are not grown the need for vitamin C often
becomes acute. There is also considerable evidence that in sec-
tions where and when green and yellow vegetables are not
readily accessible the need for vitamin A also is acute.
The level of food intake of population groups is determined by
food surveys. The level of intake of each individual nutrient is
assessed from values obtained from tables based on average
values. Surveys would furnish more accurate information if
the intake of any nutritional factor were based on values that
were valid for the environment studied. The increase in accuracy
would be particularly marked if values were at hand for foods
supplying a major quantity of a given item. In this bulletin
the carotene and ascorbic acid contents of many Florida-grown
vegetables, edible wild plants, and sub-tropical fruits are reported.
These determinations were made with the thought that, in addi-
tion to supplying data on carotene and ascorbic acid content of
the people's food, some little-known but easily-grown and widely
distributed plants might contain an unusually high concentra-
tion of these factors and become important additions to the
nutritionists' armamentarium. Since the idea of increasing
intakes of nutrients through raising their levels in fruits and
vegetables is attractive and rational, some supplementary data
are included. These data suggest how the level of carotene and
ascorbic acid in plants may be affected either by fertilization or
by selection of variety. Such information may help to point the
way which will lead to the production of foods richer in these
essential nutrients.

Methods
Collection of Samples.-Samples of fruits and vegetables were
collected from both commercial and home gardens and groves,
from experimental plots at the Agricultural Experiment Sta-
tion and Substations, and from local markets. Only samples that








Levels of Carotene and Ascorbic Acid in
Florida-Grown Foods

By R. B. FRENCH and 0. D. ABBOTT
It is generally recognized that intake of both carotene
provitaminn A) and ascorbic acid (vitamin C) in a large portion
of the population is far below optimum. In Florida during the
part of the year when citrus fruits are scarce and in sections
where these fruits are not grown the need for vitamin C often
becomes acute. There is also considerable evidence that in sec-
tions where and when green and yellow vegetables are not
readily accessible the need for vitamin A also is acute.
The level of food intake of population groups is determined by
food surveys. The level of intake of each individual nutrient is
assessed from values obtained from tables based on average
values. Surveys would furnish more accurate information if
the intake of any nutritional factor were based on values that
were valid for the environment studied. The increase in accuracy
would be particularly marked if values were at hand for foods
supplying a major quantity of a given item. In this bulletin
the carotene and ascorbic acid contents of many Florida-grown
vegetables, edible wild plants, and sub-tropical fruits are reported.
These determinations were made with the thought that, in addi-
tion to supplying data on carotene and ascorbic acid content of
the people's food, some little-known but easily-grown and widely
distributed plants might contain an unusually high concentra-
tion of these factors and become important additions to the
nutritionists' armamentarium. Since the idea of increasing
intakes of nutrients through raising their levels in fruits and
vegetables is attractive and rational, some supplementary data
are included. These data suggest how the level of carotene and
ascorbic acid in plants may be affected either by fertilization or
by selection of variety. Such information may help to point the
way which will lead to the production of foods richer in these
essential nutrients.

Methods
Collection of Samples.-Samples of fruits and vegetables were
collected from both commercial and home gardens and groves,
from experimental plots at the Agricultural Experiment Sta-
tion and Substations, and from local markets. Only samples that








Levels of Carotene and Ascorbic Acid in
Florida-Grown Foods

By R. B. FRENCH and 0. D. ABBOTT
It is generally recognized that intake of both carotene
provitaminn A) and ascorbic acid (vitamin C) in a large portion
of the population is far below optimum. In Florida during the
part of the year when citrus fruits are scarce and in sections
where these fruits are not grown the need for vitamin C often
becomes acute. There is also considerable evidence that in sec-
tions where and when green and yellow vegetables are not
readily accessible the need for vitamin A also is acute.
The level of food intake of population groups is determined by
food surveys. The level of intake of each individual nutrient is
assessed from values obtained from tables based on average
values. Surveys would furnish more accurate information if
the intake of any nutritional factor were based on values that
were valid for the environment studied. The increase in accuracy
would be particularly marked if values were at hand for foods
supplying a major quantity of a given item. In this bulletin
the carotene and ascorbic acid contents of many Florida-grown
vegetables, edible wild plants, and sub-tropical fruits are reported.
These determinations were made with the thought that, in addi-
tion to supplying data on carotene and ascorbic acid content of
the people's food, some little-known but easily-grown and widely
distributed plants might contain an unusually high concentra-
tion of these factors and become important additions to the
nutritionists' armamentarium. Since the idea of increasing
intakes of nutrients through raising their levels in fruits and
vegetables is attractive and rational, some supplementary data
are included. These data suggest how the level of carotene and
ascorbic acid in plants may be affected either by fertilization or
by selection of variety. Such information may help to point the
way which will lead to the production of foods richer in these
essential nutrients.

Methods
Collection of Samples.-Samples of fruits and vegetables were
collected from both commercial and home gardens and groves,
from experimental plots at the Agricultural Experiment Sta-
tion and Substations, and from local markets. Only samples that







Florida Agricultural Experiment Station


had been harvested recently under good conditions were obtained.
The samples were chosen so that they were uniform with respect
to size, shape, color and stage of maturity.
Preparation of Samples.-Each individual sample was taken
from a composite made from several pounds of the fruit or veg-
etable to be analyzed. Only edible portions were included in the
sample. Four dozen fruits, root crops, tubers, cabbage, head
lettuce or cauliflower were cut longitudinally and a section was
removed of such size that the first aliquot could be handled by a
Waring blendor. This volume of material was then chopped or
ground in the blendor and convenient aliquots were removed
from it for analysis. Similar sub-dividing and aliquoting pro-
cedures were used on all samples.
Carotene.-In preliminary work the procedure (10)1 of sapon-
ification and extraction with peroxide-free ethyl ether, and of
partition of carotenoids between ether and 90 percent methyl
alcohol was employed. Carotene was determined in a Cenco
photelometer using a broad band filter with maximum transmis-
sion at 450 millimicrons and S M A carotene was used as a
standard.' This carotene was recrystallized according to the
method of Fraps and Kemmerer (2).
In later work and for most of the analyses here reported, a
technic which checked well in most instances with the preceding
method was followed. This method (8) involved simultaneous
grinding and extraction of plant pigments in a Waring blendor
with subsequent pigment separation upon selected differential
adsorbents-usually Baker's calcium dibasic phosphate. Caro-
tene was determined in petroleum ether or Skellysolve B solution,
using a Cenco spectrophotelometer. Readings were taken at 450
and 480 millimicrons. Where the ratio between the logs of I/I
at 450/480 varied outside of 1.12 to 1.21 an absorption curve for
the solution was made. Lycopene was the usual cause for a de-
crease in the ratio, and readings at 505 millimicrons were included
in these instances. Simultaneous equations using the following
absorption coefficients were set up and allowance was made for
the lycopene: For carotene and lycopene at 450 millimicrons,
247,208; at 480, 220,264; at 505, 50,298. The carotene values
were determined and the lycopene values obtained from
Miller (7).

SItalic figures in parentheses refer to "Literature Cited" in the back of
this bulletin.







Florida Agricultural Experiment Station


had been harvested recently under good conditions were obtained.
The samples were chosen so that they were uniform with respect
to size, shape, color and stage of maturity.
Preparation of Samples.-Each individual sample was taken
from a composite made from several pounds of the fruit or veg-
etable to be analyzed. Only edible portions were included in the
sample. Four dozen fruits, root crops, tubers, cabbage, head
lettuce or cauliflower were cut longitudinally and a section was
removed of such size that the first aliquot could be handled by a
Waring blendor. This volume of material was then chopped or
ground in the blendor and convenient aliquots were removed
from it for analysis. Similar sub-dividing and aliquoting pro-
cedures were used on all samples.
Carotene.-In preliminary work the procedure (10)1 of sapon-
ification and extraction with peroxide-free ethyl ether, and of
partition of carotenoids between ether and 90 percent methyl
alcohol was employed. Carotene was determined in a Cenco
photelometer using a broad band filter with maximum transmis-
sion at 450 millimicrons and S M A carotene was used as a
standard.' This carotene was recrystallized according to the
method of Fraps and Kemmerer (2).
In later work and for most of the analyses here reported, a
technic which checked well in most instances with the preceding
method was followed. This method (8) involved simultaneous
grinding and extraction of plant pigments in a Waring blendor
with subsequent pigment separation upon selected differential
adsorbents-usually Baker's calcium dibasic phosphate. Caro-
tene was determined in petroleum ether or Skellysolve B solution,
using a Cenco spectrophotelometer. Readings were taken at 450
and 480 millimicrons. Where the ratio between the logs of I/I
at 450/480 varied outside of 1.12 to 1.21 an absorption curve for
the solution was made. Lycopene was the usual cause for a de-
crease in the ratio, and readings at 505 millimicrons were included
in these instances. Simultaneous equations using the following
absorption coefficients were set up and allowance was made for
the lycopene: For carotene and lycopene at 450 millimicrons,
247,208; at 480, 220,264; at 505, 50,298. The carotene values
were determined and the lycopene values obtained from
Miller (7).

SItalic figures in parentheses refer to "Literature Cited" in the back of
this bulletin.







Carotene and Ascorbic Acid in Foods


How various procedures affect carotene values when lycopene
is present is depicted in Table 1. A sample of pink guava blended
in ether was extracted 6 times with 90 percent methyl alcohol,
another sample was extracted once, and a third was unextracted.
The 3 samples were then adsorbed on 2 lots of dibasic phosphate.
Extraction with 90 percent methyl alcohol removed a little
lycopene. The 2 lots of phosphate varied slightly in their adsorp-
tive power. The spectral data showed that even after diphasic
separation, adsorption, or both, still almost one-half of the
color in the solution was due to lycopene.

TABLE 1.-CAROTENE VALUES IN PINK GUAVAS AFTER DIFFERENT
EXPERIMENTAL PROCEDURES.
Carotene found after adsorption on 2
different lots of dibasic calcium phos-
phate, computed from absorption data
Treatment of Sample at:
I 450 Millimicrons 1450/505 Millimicrons
Lot 1 Lot 2 Lot 1 Lot 2
Microgms Microgms Microgms Microgms
Extracted 6 times with 90%
MeOH before absorption---............ 5,440 5,100 2,960 2,750
Extracted once with 90% MeOH
before absorption ...................... 5,500 5,260 3,070 3,070
No extraction ....................... ... 5,600 5,280 3,120 2,990

In routine work with the spectrophotelometer an exit slit of
5 millimicrons was used, but when pigments other than carotene
were present a 2.5 millimicron slit was substituted. In both
cases the 0.5 mm entrance slit was employed. The total spectral
regions isolated in each case were 7.0 and 4.5 millimicrons,
respectively.
Ascorbic Acid.-The volumetric determination of ascorbic acid
with Tillman's indicator, or sodium 2,6 dichlorobenzenoneindo-
phenol, has been used general (3). At first 8 percent
CC13COOH was the extracting medium, but later 2 percent
HPO was used (9). In special cases where the amount of
ascorbic acid to be determined was small, or color interfered with
the endpoint of the titration, either the photometric (1) or
electrometric (4) procedure was used as alternate. These 3
methods were in agreement when used on the same samples.
When titration values were unusually large or suspected, con-
firmation was obtained by checking on the destruction of the
titration values by an oxidase prepared either from squash (12)






Florida Agricultural Experiment Station


or cucumber (11). When the presence of dehydroascorbic acid
was suspected, reduction was accomplished with H2S (6).
Three factors commonly may affect the dye titration. Some
indicator absorption occurs with certain types of colloidal mate-
rial, released in grinding the sample. Bahia grass and cabbage
are examples of the type. Blanching in acid eliminates this
factor. This effect should be checked for each different kind of
sample, since the apparent titration may be higher than the
real value.
Ascorbase is present in such plants as cabbage, cucumbers,
summer squash and white sapote. In preparing aliquots of such
materials for analysis any disorganization of cell tissue must be
accompanied by inactivation of the enzyme, by either heat or
acid. Cabbage furnishes an example of a sample that shows
both the action of ascorbase and adsorption of indicator. Each
aliquot was blended, filtered and titrated, and the values represent
the comparative milligrams of ascorbic acid determined in a 100-
gram sample as follows:
Sample titrated
Immediately ........................ ....... ......... ............... 3.0
After standing 10 minutes ................................................. 3.0
After blending in 2% HPO, (slightly cloudy) ............ 24.3
After blanching (cloudy).............................. ......... 26.0
After blanching in 2% HPO, (clear) ...............................23.0

Dye equivalent to 3 milligrams of ascorbic acid was absorbed
and 23 milligrams, the real value for ascorbic acid, was destroyed
by the enzyme.
Other materials may be present that will decolorize the indi-
cator in addition to those mentioned in the literature (13).
When oxalic acid is used as the extracting agent with mangos,
slightly colored solutions result containing presumably flavones
that reduce the indicator.

Experimental
Average Values.-Data on average values of carotene and
ascorbic acid as found in Florida-grown fruits and vegetables are
presented in Table 2. These figures represent the nutritive value
of 100 grams of the edible portion of selected foods, expressed
in micrograms of total carotene and in milligrams of ascorbic
acid. It will be noted that these 2 constituents vary widely in
different fruits and vegetables. Carotene varies from a mere
trace in the slightly or non-pigmented orange, grapefruit, lime,






Florida Agricultural Experiment Station


or cucumber (11). When the presence of dehydroascorbic acid
was suspected, reduction was accomplished with H2S (6).
Three factors commonly may affect the dye titration. Some
indicator absorption occurs with certain types of colloidal mate-
rial, released in grinding the sample. Bahia grass and cabbage
are examples of the type. Blanching in acid eliminates this
factor. This effect should be checked for each different kind of
sample, since the apparent titration may be higher than the
real value.
Ascorbase is present in such plants as cabbage, cucumbers,
summer squash and white sapote. In preparing aliquots of such
materials for analysis any disorganization of cell tissue must be
accompanied by inactivation of the enzyme, by either heat or
acid. Cabbage furnishes an example of a sample that shows
both the action of ascorbase and adsorption of indicator. Each
aliquot was blended, filtered and titrated, and the values represent
the comparative milligrams of ascorbic acid determined in a 100-
gram sample as follows:
Sample titrated
Immediately ........................ ....... ......... ............... 3.0
After standing 10 minutes ................................................. 3.0
After blending in 2% HPO, (slightly cloudy) ............ 24.3
After blanching (cloudy).............................. ......... 26.0
After blanching in 2% HPO, (clear) ...............................23.0

Dye equivalent to 3 milligrams of ascorbic acid was absorbed
and 23 milligrams, the real value for ascorbic acid, was destroyed
by the enzyme.
Other materials may be present that will decolorize the indi-
cator in addition to those mentioned in the literature (13).
When oxalic acid is used as the extracting agent with mangos,
slightly colored solutions result containing presumably flavones
that reduce the indicator.

Experimental
Average Values.-Data on average values of carotene and
ascorbic acid as found in Florida-grown fruits and vegetables are
presented in Table 2. These figures represent the nutritive value
of 100 grams of the edible portion of selected foods, expressed
in micrograms of total carotene and in milligrams of ascorbic
acid. It will be noted that these 2 constituents vary widely in
different fruits and vegetables. Carotene varies from a mere
trace in the slightly or non-pigmented orange, grapefruit, lime,









TABLE 2.-AVERAGE CAROTENE AND ASCORBIC ACID IN THE EDIBLE PORTION
OF FLORIDA FRUITS AND VEGETABLES.

Name Carotene Ascorbic Acid


Fruit
Avocado .................................
Banana ....................................
Blackberries ................. .........
Bullock's Heart ..........................
Canistel ........ ..... .........................
Cantaloupes ................................
Dates ......... ......... ..........
Fig ..............................................
Gooseberry, Ceylon ...............
Grapefruit ..................................
Grapes ......................................
Guavas, pink ...................:..........
Guavas, white ........ .............
Huckleberries ............................
Jujube ................................. ...
Lemon ................. .................
Lime, Persian ............................
Lime, Key ..................................---------------
Mango ..........................................
Orange ......................................
Papaya .......................................
Peach ...................... .......
Pear ...........................................
Persimmon ...............................
Pineapple ...........................
Plum; red ....................................
Plum, yellow ............ ...
Sapote, white ................ ....-.....--
Strawberry ..................---........-
Tangerines ...........................-......
W watermelons ............................
Vegetable
Bean, snap .................................
Bean, lima ..............................
Beet ............................................
Beet greens ................................
Broccoli ........................................
Cabbage ...................................
Carrot .............. .....................
Cauliflower .................................
Celery, Pascal .......................
Celery, bleached ........---........-..
Chayotes ...................................
Collards .....................................-
Corn, yellow ..........................
Cucumber ....................................
Eggplant .................................
Horseradish ................................
Lettuce .......................------..
Mustard greens ........................
Okra ..........................................
Onion .................... .................
Parsley ........................................
Peas, English .......................
Peas, field ..............................
Peppers, green ........................
Potato, sweet .........................
Potato, white .........................


Microgms/100 gms
290
210
220
0
330
1,960
400
540
1,190
0
0
3,100
0
110
0
0
0
0
3,100
trace
81
30
10
4,330
85
370
1,580
0
75
790
0

280
120
65
4,680
2,140
176
4,990
60
320
0
50
6,590
80
0
0

trace
4,540
330
0
4,500
310
275
330
4,290
0


Mgms/100 gms
21
15
12
41
53
108
0
0
194
42
5
310
46
9
56
50
41
44
30
52
41
3
15
15
37
'2
2
45
30
33
7

17
28
10
130
66
54
5
37
8
14
9
139
28
6
7
160
7
140
45
3
176
35
46
172
26
29








TABLE 2.-AVERAGE CAROTENE AND ASCORBIC ACID IN THE EDIBLE PORTION
OF FLORIDA FRUITS AND VEGETABLES. (Continued)

Name Carotene Ascorbic Acid


Vegetable
R adish ....................................
Rutabaga ...................................
Spinach ........................................
Spinach, New Zealand...............
Squash, winter .-...................
Squash, summer ........................
Tom ato ............... ................ ...
Turnip ......................... .........
Turnip greens .................
Wild Greens*
Chickweed, Stellaria media
Leafy stems ..........................
White Dutch clover, Trifolium
repens. Leaves and young
shoots ............................ .....
Alyce clover, Alysicarpus va-
ginalis. Leaves and young
shoots .....................................
Bur clover, Medicago hispida.
Leaves and young shoots......
Coffeeweed, Cassia tora.
Young shoots and leaves....
Water cress, Rorippi nastur-
tium-aquaticum. Salad -
leaves and young shoots......
False dandelion, Pyrrhopappus
carolinianus. Leaves and
shoots ............ ..................
Henbit, Lamium amplexi-
caule. Young shoots..........
Lambs quarters, Chenopod-
ium album. Leaves and
young shoots .......... ........
Mature leaves .....................
Peppergrass, Lepidium vir-
ginicum. Salad, young
leaves and shoots....... ....
Parietaria floridana. Young
leaves and shoots ..........
Pennywort, Hydrocotyle sp.
Salad, leaves; or leaves
stemmed ............... .............
Pokeweed, Phytolacca rigida.
New shoots ** .................
Spiderwort, Tradescantia flu-
minensis. Young leaves and
stem s ..... ........... ....... ......
Spanish moss (winter) ***
Tillandsia usneoides ............
Thistle, Cirsium sp. Youn g
stems peeled ........ ...........
Violet leaves, Viola floridana....


Microgms/100 gms
trace
790
4,050
4,220
2,580
85
2,860
0
5,055


4,270


7,600


10,500

8,700

57,500


8,660


6,050

5,450


7,200
4,720


10,160

8,130


6,060

5,220


5,720

1,500

2,210
7,560


Mgms/100 gms
10
31
75
36
10
5
19
24
157


The wild greens were selected and identified by Mr. Erdman West, Department of
Plant Pathology at the Main Station.
** Roots of pokeweed are classified as poisonous. Berries and old leaves have been
spoken of as possibly toxic. White rats will eat both berries and leaves without apparent
harm.
*** Spanish moss is included as a matter of interest, since cattle frequently are seen
eating it during winter months.







Carotene and Ascorbic Acid in Foods


lemon and guava, to 3,100, 3,100, and 4,330 micrograms in the
highly pigmented pink guava, mango and persimmon, respec-
tively. In slightly pigmented vegetables, as represented by
bleached celery, cucumber, eggplant, white potato and turnip,
carotene was not present in measurable quantities, while in green
and yellow vegetables comparatively high- values were found.
The data show, however, that the highest carotene values were
found in certain edible wild plants; for water cress, Bur clover,
pepper grass, Alyce clover, and coffee weed the values were 8,660,
8,700, 10,160, 10,500 and 57,500 micrograms, respectively.
Among cultivated vegetables the highest carotene values were
found in cantaloupes and sweet potatoes and especially in green
leafy plants, spinach, mustard, collards and turnip greens.
In addition to being excellent sources of carotene the pink
guava and Ceylon gooseberry were the fruits highest in ascorbic
acid. The Ceylon gooseberry had more than 3 times as much
ascorbic acid as the orange, while the pink guava had more than
6 times that of the orange. Among the vegetables, broccoli, the
usual greens, and cabbage were highest in ascorbic acid. But
again one can see that certain of the wild plants were consid-
erably higher in ascorbic acid than the cultivated ones. Bur
clover had an average of 191 milligrams, violets 257 milligrams,
and coffee weed 412 milligrams of ascorbic acid per 100 grams.
Emphasis on high nutritive value is obtained through the
device used in Table 3. Here the amount of either carotene or
ascorbic acid found in a food serving is quoted as percent of the
daily requirement. Any individual serving that furnishes a large
fraction of 75 milligrams of ascorbic acid or 5,000 units of vitamin
A, the day's total estimated needs, would be rated as an excel-
lent food source and one that furnished less than 10 percent of
the need would be rated as a poor one. This table indicates that
only few fruits and vegetables can be classed as excellent sources
of either or both ascorbic acid and carotene. In this respect the
position of semi-tropical fruits and of greens should be especially
noted.
Variety Data.-Relative differences in levels of carotene .and
ascorbic acid in several varieties of fruits and vegetables are
given in Table 4. These include avocado, grapefruit, guava,
orange, mango, papaya, pineapple, plums, snap beans, carrots,
celery, field peas, squash and watermelon. The values illustrate
both the large and the small variations that obtain between vari-
eties in levels of carotene and ascorbic acid.








Florida Agricultural Experiment Station


TABLE 3.-PERCENTAGE OF RECOMMENDED DAILY INTAKE OF CAROTENE AND
ASCORBIC ACID AS CONTRIBUTED BY AN AVERAGE SERVING OF SOME FLORIDA-
GROWN FRUITS AND VEGETABLES.


Name


Fruit
Guava, pink ...................
Gooseberry, Ceylon.......
Mango ............................
Persimmon .....................
Plum, yellow ................
Orange ............................
Grapefruit .....................
Jujube ......... ................
Sapote ....---......................
Papaya .......................
Vegetables
Collards .............. .....
Turnip greens ...............
Beet greens ..-.................
Mustard greens .............
Spinach .......................
Sweet potato ..........
Tomato .......................
Broccoli ................ ...
Carrots ...................
Winter squash ............-

Rutabagas .....................
Cabbage .........-........
White potato ...........


Average Serving



1 pared and seeded..........
1 cup .............. ......... ......
% pared and seeded........
1 small seeded ..............
3 stoned ............................
1/2 CU P .-.-------------- -- .-.--- -
1/2 cup ...................
1/2 cup ---------------------------..............----
1 pared and seeded ..........
1 pared and seeded ..........
1/2 seeded without rind....

1 cup leaves ............ ..
1 cup leaves ............. ..
1 cup leaves ..............
1 cup leaves ....... .........
1 cup leaves ......................
1 pared, 150 gms............
1 small, cored ..............
1 cup ...............
1 large, scraped .......
1 cup seeded, without
rind .....................
% cup pared ...............
1 cup ....-----...............
1 pared, 150 gms ......


Contribution to Daily
Requirement in Per-
cent
Ascorbic
Carotene Acid

86 415
33 260
86 40
120 20
44
70
56
60
60
55

183 186
139 210
130 174
126 187
117 100
157 47
79 25
59 79


Based on 75 milligrams for vitamin C and 5,000 I. U. for vitamin A.

Variations in carotene and ascorbic acid contents of different
varieties of mangos and guavas are striking. Perhaps the out-
standing example of varietal differences is seen in the guava.
In 7 varieties of guavas studied there were no measurable
amounts of carotene in 3, in either skin or flesh, even though some
were quite yellow,'while in the remaining varieties the carotene
ranged from 1,900 to 4,890 micrograms per 100 grams. The
ascorbic acid varied from 44 to 389 milligrams per 100 grams.
Varieties of guavas that were highest in carotene were also
highest in ascorbic acid with the exception of the Donaldson,
which had little or no carotene and was among the highest in
ascorbic acid. The large differences in ascorbic acid content,
and the complete separation of carotene-forming characteris-
tics are outstanding and probably are associated with specific
chromosomes.







TABLE 4.-CAROTENE AND ASCORBIC ACID LEVELS IN FLORIDA FRUITS AND
VEGETABLES AS INFLUENCED BY VARIETY.

Name Variety Carotene I Ascorbic Acid
Fruit Microgms/100 gms Mgms/100 gms
Avocado ........... Pollock .................... 510 37
Walden ................... 410 28
Collinson .................. 280 7
Booth 8 .................. 240 10
Trapp ...................... 140 31
Lulu ........................ 130 13
Grapefruit ..... Foster, pink seed-
less .................... 0 53
Florida Common .... 0 42
Seedling ................. 0 44
Guava .......... Acid ........................ 3,020 389
Indian Red Skin...... 2,580 388
Stone ...................... 4,890 341
No. 57828 ................ 1,900 139
Donaldson .............. 0 372
Redland .................. 0 48
Supreme .............. 0 44
Oranges ......... Parson Brown ........ trace 51
Hamlin .................... trace 50
Pineapple ................ trace 64
Valencia ................. trace 44
Satsuma .................. trace 24
Temple .................... trace 48
Mango ........... Haden ...................... 5,000 (3,480)2 18 (14)
Amini ...................... 3,370 (3,370) 12 (12)
Cecil ----------.. ..... 3,760 (2,440) 42 (43)
Cambodiana .......... 2,380 (2,060) 28 (29)
Edward .................... 2,070 58
Paheri ...................... 3,360 17
Martin ...................... 2,640 14
Simmonds ................ 4,200 33
Samini .................... 1,200 24
Saigon .................... 2,840 38
Stannard ................ 5,410 54
Mulgoba .................. 2,130 31
Amini, round .......... 2,560 14
Pineapple ....... Abachi .................... 85 36
Sugar Loaf ............ 85 40
Plums ............... Wild Goose ............ 37 1
American Yellow.... 158 2
Vegetable
Bean, snap ..... Kentucky Wonder.. 425 15
Valentine ................ 281 17
Bountiful ................ 277 26
Tender Green .......... 253 21
Plentiful ................ 157 4
Carrots ........... Imperator .............. 5,130 5
Nantes ...................... 4,850 4
Celery ............. Summer Pascal ...... 347 8
Golden Plume ........ trace 14
Field peas ..... Sugar Crowder ...... 253 49
Lady Finger ............ 250 41
Squash ............ Table Queen ........... 165 5
Early Prolific .......... 72 6
Cocozelle .................. 22 4
Watermelon .. Tom Watson ........... 0 7
Cuban Queen .......... 0 7
Leesburg .................. 0 8

1 From Mr. M. U. Mounts, County Agent, West Palm Beach.
Figures in ( ) refer to slightly immature fruit.







Florida Agricultural Experiment Station


There was also considerable variation in both carotene and
ascorbic acid among the 14 varieties of mangos. The highest
carotene values were found in Stannard (5,410 micrograms) and
in Haden (5,000 micrograms) and the lowest in Edward (2,070
micrograms) and in Samini (1,200 micrograms). While Stan-
nard was high in both carotene and ascorbic acid, Haden was
high in carotene but among the lowest in ascorbic acid. Edward,
which was low in carotene, was highest in ascorbic acid.
Data on 36 tomato varieties analyzed during the years 1942-44
are found in Table 5. Ascorbic acid content of these ranged from
11 to 27 milligrams and carotene from none to 3,400 micrograms
per 100 grams of fresh fruit.
Figures in parentheses next to carotene values are the values
that were obtained after chromatography and were computed
from the absorption reading at 450 millimicrons. The difference
between the 2 sets of values is due to lycopene that was not
absorbed in the chromatographic procedure and is similar to the
problem discussed under Table 1. Such a comparison suggests
the wide gulfs that improved procedures help to cross.
Yearly checks on value within the same variety suggest that
environmental conditions not under control may affect the level
of carotene particularly. The coefficient of correlation between
level of ascorbic acid and carotene equals -.16, and between the
former and the total pigment measured is -.66. These cor-
relative trends suggest that environmental factors favoring
lycopene synthesis are unfavorable to ascorbic acid production
and have little to do with carotene formation.
Fertilization under Field Conditions.-New York lettuce grown
at Gainesville and given an adequate level of major fertilizer
materials with minor element supplementation was analyzed for
ascorbic acid. The minor elements used included borax, zinc,
manganese and copper, both in combination and singly, together
with a "complete" supplementation with 64 elements. For the
64 samples analyzed the level of ascorbic acid ranged from 4.6
to 6.6 milligrams per 100 grams, which is only a slight variation.
In like manner, cabbage given minor element supplementation
(Table 6A) gave little if any response by shifting of either caro-
tene or ascorbic acid levels. In neither of the above experiments
did a known soil deficiency exist, and the results suggest that the
addition of minor elements under such conditions had little
influence on ascorbic acid or carotene production.




TABLE 5.-ASCORBIC ACID AND CAROTENE IN SEVERAL VARIETIES OF TOMATOES.t
I Ascorbic Acid Carotene
Tomato Variety I Mgms/100 gms Microgms/100 gms
I 1942 1943 1944 1942 | 1943 1944
Greenhouse Pan America .................. ..........--- 17.9 18.0 19.5 1,456 (4,018)* 867 (3,030) 1,142 (1,190)
Rutgers .................. .......................... 27.0 17.0 17.8 1,139 (1,559) 819 (4,084) 1,400 (1,454)
Grothen's Globe ................................................ 24.5 18.3 14.5 1,172 (2,196) 1,796 (2,504) 1,104 (1,148)
Stokesdale .............................................................. 18.8 15.5 1,904 (2,539) 477 (2,636)
N well .................................................................... 20.8 22.0 1,699 (2,591) 906 (2,546)
Ruby Queen .......................................................... 18.5 17.0 1,871 (2,610) 1,071 (3,168)
Cardinal King ........ -...................................... 18.0 18.3 1,906 (2,573) 943 (2,660)
Master Marglobe ................................................. 17.2 18.8 3,403 (4,963) 1,010 (1,050)
Valiant .............................................. ................... 27.2 18.5 1,489 (2,042) 1,710 (3,880)
Pritchard .. ..................................................... 18.3 17.8 557 (3,304) 1,310 (1,364)
M arhio ...... ................ ................. ..... 22.5 701 (2,740)
Cleo .............................................. ...... 19.0 0 (2,288)
W 20-1 ............................. ................ ........... 24.8 1,264 (1,316)
W 41-2 ................................................................... 18.3 1,122 (1,176)
W 43-1 ................................................................... 20.8 1,048 (1,090)
W 57-2 ..................................................................... 19.0 1,320 (1,374)
Louisiana Dixie .................................................... 17 2,207 (3,642)
No Substitute .........................................-............ 21.3 1,354 (3,579)
Bloomdale Self Topper ........................................ 17.0 2,233 (3,836)
Bloomdale Midseason No. 15.............................. 27.0 1,187 (3,327)
Break O'Day ......................................................... 15.0 1,615 (4,185)
.Ponderosa .............................................................. 20.2 1,060 (2,227)
Oxheart ..............................-- -.....-.............-.... 10.8 1,189 (1,811)
Lange's Earliana .................................................. 16.3 1,417 (5,012)
Pearson .................................................................. 13.3 2,562 (4,955)
Table Talk ......................................................... 21.0 2,657 (4,683) o
Sweetm eat .............................................................. 18.7 1,456 (5,550)
Beefsteak .............................................................. 16.8 1,504 (1,800)
Clark's Special ..................................................... 20.6 1,497 (3,497)
Fisher ............................................-........................ 21.5 1,231 (3,802)
Com et ....................... ........... ...... ..... ................. -24.2 1,427 (1,969)
Santa Clara Canner ........................................... 15.8 2,395 (3,217)
Bonny Best .......... ................................ 22.0 1,823 (4,723)
Victor .................................-................. 14.7 1,443 (3,533)
Glovel ................................... .......... 23.0 1,954 (3,079)
Michigan State Forcing ...................................... 18.8 _1,982 (3,006)_
t From Vegetable Crops Laboratory. Bradenton.
Figures in ( ) include lycopene not separated by chromotography.








Florida Agricultural Experiment Station


TABLE 6.-EFFECT OF FERTILIZER UPON LEVEL OF ASCORBIC ACID AND
CAROTENE.
Fertilizer Ascorbic Acid Carotene
Cabbage Variety Supplement Mgms/100 gms Microgms/100 gms
A. Cabbage with Minor Element Supplementation *

Glory of Enkhuizen None .................. 51 220
Glory of Enkhuizen Mn, Zn, B, Fe 47 160
Golden Acre............ None .................. 54 90
Golden Acre............ Mn, Zn, B, Fe 1 50 150
B. Papaya Reaction to Potash Level **

Papaya, Betty........ No. K.O .............. 41 110
5% KO .............. 47 50
10% K O ............ 45 70
15% K O ............ 51 90
!20% KKO ............I 41 10
C. Sudan-Sorghum Cross Grown in Pot Culture under and not under
Cheesecloth with Nitrate and Ammonia as Sources of Nitrogen ***
Nutrient Treat-
ment Ascorbic Acid Carotene
N- 13.2 Milli- Mgms/100 gms Microgms/100 gms
mols/L _
P -2.2 Milli i
mols/L I
K -2.2 Milli- I Shade No Shade Shade No Shade
mols/L I

NO, NHI
0 100 61 38 14,970 8,200
25 75 51 39 14,150 13,060
50 50 48 36 14,300 12,730
75 25 56 35 14,000 11,870
100 0 57 55 13,930 9,490
From Horticulture Department, Main Station.
** From Sub-Tropical Station, Homestead.
*** In cooperation with Aeronomy Department, Main Station.

Papayas of the Betty variety that had received different levels
of potassium fertilization were analyzed (Table 6B). The fruits
were grown at Homestead. All received a fertilizer containing
4 percent nitrogen and 8 percent phosphorus, with potassium
at 0, 5, 10, 15 and 20 percent levels.
Ascorbic acid varied from 41 to 51 milligrams and carotene
from a trace up to 106 micrograms per 100 grams of fruit. There
was little correlation between the levels of either ascorbic acid
or carotene in the papayas with level of potash fertilization,
although the lowest carotene value was associated with the
highest level of potash and the highest carotene with no potash.














TABLE 6.-EFFECT OF FERTILIZER UPON LEVEL OF ASCORBIC ACID AND CAROTENE.-(Concluded)
D. Sudan and Bahia Grass, Tomato and Tobacco Leaves Grown in Pot Culture with Nitrate and Ammonia Nitrogen,
and High, Medium and Low Levels of Phosphorus and Potassium.


Nutrient Solution

N=13.2 millimols/L
High P. K.=21.3 millimols/L
Medium P. K.=2.2 millimols/L
Low P. K.=0.2 millimols/L .
P and K were used in all treat-
ments and where not indicated
were given at a median level.
With the Sudan grass the NH4
marked series was given %-
NH4 and 1/2 NOs nitrogen, Hoag-
land's A-M solution furnished
the micro elements.


Treatment


NOs .....................
NOj high P..........
NOs low P............
NOs high K..........
NO low K............
NH, ......................
NH4 high P..........
NH. low P...........
NH, high K..........
NH, low K............


Ascorbic Acid-Mgms/100 gms


Sudan


Bahia Tomato Tobacco
Young Mature I leaves leaves


ICarotene-Microgms/100 gms


Sudan


280
265
1,490

15,350
12,500
20,200.
15,900
25,000


Bahia ITomato
Young IMature I leaves


1,150
3,380
1,320
1,220
760
1,620
910
1,310
1,370
1,540


820
950
1,050
800
1,370
1,140
1,280
1,760
1,810
1,520


1,300
800
250
420
350







Florida Agricultural Experiment Station


Incidentally, somewhat more ascorbic acid and carotene were
found in the outer integument than in the flesh.
Fertilization in Pot Cultures.-A Sudan grass cross with sor-
ghum, fed a complete nutrient solution with both ammonium
and nitrate nitrogen at all quarter levels, was grown either under
or not under cheesecloth shade (Table 6C (5)). All pot exper-
iments were done in quintuplicate. Leaves collected early in the
morning were analyzed for ascorbic acid and carotene. The
ascorbic acid of the shaded plants ranged from 48 to 61 milli-
grams and of the unshaded from 35 to 55 milligrams; the caro-
tene of the shaded plants ranged from 13,930 to 14,950 micro-
grams and of the unshaded from 8,200 to 13,060. In each case
plants grown in the shade contained more of both ascorbic acid
and carotene than those grown without shade. Varying the rates
of application of nitrate and ammonia to the plants did not give
a notable effect.
Carotene and ascorbic acid were determined on greenhouse-
grown Sudan grass, Bahia, both vegetative and mature, as well
as on tomato leaves and tobacco leaves. These plants were grown
in drip culture. Table 6D (5). The nutrient solution furnished
the plants a median level of either nitrate or ammonia nitrogen
and high, median or low levels of either potassium or phosphorus.
Unless otherwise noted under treatment, the plants received a
median level of potassium and phosphorus.
The ascorbic acid in milligrams per 100 grams of fresh ma-
terial ranged for Sudan from 158 to 230, for vegetative Bahia
from 25 to 70, for mature Bahia from 12 to 17, and for tomato
leaves from 242 to 288. The carotene in micrograms per 100
grams of fresh material ranged for Sudan from 280 to 25,000,
for vegetative Bahia from 760 to 3,380, for mature Bahia from
800 to 1,810, and for tomato leaves from 250 to 1,300.
The various leaves showed little change in level of ascorbic
acid in response to variations in fertilizer applications, with 3
exceptions found in vegetative Bahia grass. Bahia grass con-
tained little ascorbic acid as compared with most leaves and the
absolute change in level of ascorbic acid was not large. Except
for these 3 cases there were only 3 others in which the variation
from the control was over 20 percent and in these 3 it was less
than 30 percent. In 12 cases out of 20 the ammonia-fed plants
ran higher in ascorbic acid than did nitrate-fed plants.
Carotene values in the same experiment showed considerably
more variation than did ascorbic acid values. Over half of them







Carotene and Ascorbic Acid in Foods


exhibited more than 30 percent variation-either higher or lower
than the controls. There was a tremendous increase in pigmen-
tation of the Sudan grass fed ammonia-nitrate-nitrogen as com-
pared with that fed only nitrate-nitrogen. It is of interest to
note with Bahia grass, a poor producer of carotene, that in 8
out of 10 possible comparisons the ammonia-fed plants contained
a larger percent of carotene and also that in the Sudan-sorghum
experiment the highest carotene values were obtained with plants
fertilized at the 100 and 75 percent ammonia-nitrogen levels.
The Bahia analyses showed the effect of maturity on levels of
ascorbic acid and carotene. The more succulent vegetative plants
were higher in these factors.

Discussion
Agreement between analyses given in this bulletin and in
representative tables is good, in the sense that individual values
fit into logical and broad classifications of value, except perhaps
with certain of the carotene values.
Carotene values found for the strongly pigmented deep green
leaves and tomatoes tend to be somewhat lower than many pub-
lished values. One suspects that some of. the higher values may
have included other pigments, as well as in certain cases other
carotenoids like lycopene, as suggested by the data in Tables 1
and 5.
Only a few fruits and vegetables have high levels of both
carotene and ascorbic acid. In the list of fruits highest in these
values are found several of the semi-tropical fruits. Among veg-
etables the high nutritive rating of the greens is outstanding.
Such values as are found in the wild greens predicate their culti-
vation and wider usefulness, particularly in salads, where they
might add not only an exotic touch but also a nutritive benefit.
From data presented in this bulletin one might conclude that
if the dietary is to be enriched in carotene and ascorbic acid
intake of foods rich in these factors should be encouraged and
as a corollary that breeding of plants to increase the level of
carotene and ascorbic acid should be undertaken.

Summary
Suggestions are made in regard to methods of analysis for
ascorbic acid and carotene. When 2-6 dichlorobenzenoneindo-
phenol is used, absorption of, and unspecificity of, the indicator







Carotene and Ascorbic Acid in Foods


exhibited more than 30 percent variation-either higher or lower
than the controls. There was a tremendous increase in pigmen-
tation of the Sudan grass fed ammonia-nitrate-nitrogen as com-
pared with that fed only nitrate-nitrogen. It is of interest to
note with Bahia grass, a poor producer of carotene, that in 8
out of 10 possible comparisons the ammonia-fed plants contained
a larger percent of carotene and also that in the Sudan-sorghum
experiment the highest carotene values were obtained with plants
fertilized at the 100 and 75 percent ammonia-nitrogen levels.
The Bahia analyses showed the effect of maturity on levels of
ascorbic acid and carotene. The more succulent vegetative plants
were higher in these factors.

Discussion
Agreement between analyses given in this bulletin and in
representative tables is good, in the sense that individual values
fit into logical and broad classifications of value, except perhaps
with certain of the carotene values.
Carotene values found for the strongly pigmented deep green
leaves and tomatoes tend to be somewhat lower than many pub-
lished values. One suspects that some of. the higher values may
have included other pigments, as well as in certain cases other
carotenoids like lycopene, as suggested by the data in Tables 1
and 5.
Only a few fruits and vegetables have high levels of both
carotene and ascorbic acid. In the list of fruits highest in these
values are found several of the semi-tropical fruits. Among veg-
etables the high nutritive rating of the greens is outstanding.
Such values as are found in the wild greens predicate their culti-
vation and wider usefulness, particularly in salads, where they
might add not only an exotic touch but also a nutritive benefit.
From data presented in this bulletin one might conclude that
if the dietary is to be enriched in carotene and ascorbic acid
intake of foods rich in these factors should be encouraged and
as a corollary that breeding of plants to increase the level of
carotene and ascorbic acid should be undertaken.

Summary
Suggestions are made in regard to methods of analysis for
ascorbic acid and carotene. When 2-6 dichlorobenzenoneindo-
phenol is used, absorption of, and unspecificity of, the indicator






Florida Agricultural Experiment Station


should be watched closely. Routinely determined values for
carotene in fruits containing lycopene, such as tomatoes and
guavas, probably have included more or less lycopene. The
values for carotene given in this report are for a pigment with
absorption characteristics indicating a mixture of alpha and
beta carotene.
Carotene and ascorbic acid values of 31 different fruits, 35
vegetables, and 17 wild greens are reported. Values in general
checked well with those in the literature. Only a few of the
commonly used fruits and vegetables can be classed as excellent
sources of either ascorbic acid or carotene or both.
The subtropical pink guava, Ceylon gooseberry and mango
are excellent sources of both carotene and ascorbic acid, while for
ascorbic acid alone the best sources are citrus, jujube, sapote
and papaya. Greens in general are excellent sources of both fac-
tors. Special attention is called to the high worth of wild greens.
Several varieties of each of 14 fruits and vegetables were ana-
lyzed for levels of carotene and ascorbic acid. In some cases
large differences in amounts of these nutrients suggest that
genetical factors controlled levels.
Minor element supplementation where deficiencies were not
apparent had no effect on levels of ascorbic acid in lettuce or
cabbage, or on carotene in the latter. The same conclusion was
reached with papayas receiving different levels of potash fer-
tilization.
Bahia grass grown in the shade was higher in carotene and
ascorbic acid, as were vegetative as compared with mature plants.
Variations in levels of phosphorus and potassium applications
produced little if any effect on levels of ascorbic acid and caro-
tene in the leaves of several plants. There was a suggestive
trend for carotene to be somewhat higher in plants fed ammonia
than in those fed nitrate-nitrogen.
Possibilities in increasing people's intake of carotene and
ascorbic acid through raising their concentration in plant foods
apparently restrict themselves largely to selecting and breeding
varieties superior in these factors rather than employing unusual
fertilization procedures.

Literature Cited
1. BESSEY, OTTO A. A method for the determination of small quantities
of ascorbic acid and dehydro-ascorbic acid in turbid and colored
solution in the presence of other reducing substances. Jour. Biol.
Chem. 126: 771-84. 1938.








Carotene and Ascorbic Acid in Foods


2. FRAPS, G. S., and A. R. KEMMERER. Purity and stability of commercial
carotene. Indus. and Engin. Chem., News Ed. 19: 846-7. 1941.

3. FRENCH, R. B., and O. D. ABBOTT. Investigation of the vitamin C
content of Florida fruits and vegetables. Effect of maturation and
cold storage on the vitamin C potency of oranges and grapefruit.
Jour. Nutr. 19: 223-32. 1940.

4. KIRK, MARY M., and DONALD K. TRESSLER. Determination of ascorbic
acid. Electrometric titration method. Indus. and Engin. Chem.,
Analyt. Ed. 11: 322-3. 1939.

5. LEUKEL, W. A., and R. B. FRENCH. The physiological response of some
grasses to different forms of nitrogen. Fla. Agr. Expt. Sta. Mim.
Circ. Nov. 1941.

6. MCHENRY, EARLE W., and MURRAY GRAHAM. Observations on the
Sestimations of ascorbic acid by titration. Biochem. Jour. 29: 2013-19.
1935.

7. MILLER, ELMER S. A precise method, with detailed calibration, for the
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8. MOORE, L. A., and RAY ELY. Extraction of carotene from plant mate-
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9. MUSULIN, R. B., and C. G. KING. Metaphosphoric acid in the extrac-
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1936.

10. PETERSON, W. J., J. S. HUGHES and H. F. FREEMAN. Determination of
carotene in forage. A modification of the Guilbert method. Indus.
and Engin. Chem., Analyt. Ed. 9: 71-2. 1937.

11. SHARP, PAUL F., DAVID B. HAND and E. S. GUTHRIE. Quantitative
determination of dissolved oxygen. Ascorbic acid oxidase method.
Indus. and Engin. Chem., Analyt. Ed. 13: 595-7. 1941.

12. TAUBER, HENRY, I. S. KLEINER and D. MISHKIND. Ascorbic acid
(vitamin C) oxidase. Jour. Biol. Chem. 110: 211-18. 1935.

13. TUBA, JULES, GEORGE HUNTER and HELEN RUTH STEELE. On the
specificity of dye titration for ascorbic acid. Can. Jour. Res. 24B:
37-45: 1946.




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