• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Board of control and staff
 Introduction
 Review of literature
 Table of Contents
 Physical and chemical characte...
 Experimental procedure
 Experimental results and discu...
 Summary
 Literature cited
 Tables 8-13






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 511
Title: Naringin, a bitter principle of grapefruit
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027259/00001
 Material Information
Title: Naringin, a bitter principle of grapefruit occurrence, properties and possible concerns
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 29, 6 p. : ill. ; 23 cm.
Language: English
Creator: Kesterson, J. W
Hendrickson, Rudolph
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1953
 Subjects
Subject: Glucosides   ( lcsh )
Grapefruit -- Composition   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 27-29.
Statement of Responsibility: J.W. Kesterson and R. Hendrickson.
General Note: Cover title.
General Note: "A contribution from the Citrus Experiment Station"--T.p.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027259
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000925804
oclc - 18269492
notis - AEN6460

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Board of control and staff
        Page 2
        Page 3
    Introduction
        Page 5
    Review of literature
        Page 5
        Page 6
        Page 7
    Table of Contents
        Page 4
    Physical and chemical characteristics
        Page 8
        Page 9
    Experimental procedure
        Page 10
        Collection of samples
            Page 10
            Page 11
            Page 12
        Methods of analysis
            Page 13
    Experimental results and discussion
        Page 14
        Naringin content of whole grapefruit and shaddock
            Page 14
            Page 15
            Page 16
            Page 17
            Page 18
            Page 19
            Page 20
            Page 21
            Page 22
        Naringin content of juice
            Page 23
        Distribution of naringin
            Page 23
            Page 24
        Component parts of grapefruit and shaddock fruits
            Page 25
    Summary
        Page 26
    Literature cited
        Page 27
        Page 28
        Page 29
    Tables 8-13
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





MAR 16 1953
January 1953


Bulletin 5i1


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA
(A contribution from the Citrus Experiment Station)



Naringin, A Bitter Principle of

Grapefruit

Occurrence, Properties and Possible Utilization
J. W. KESTERSON and R. HENDRICKSON


Fig. 1.-Naringin crystals magnified 40 times.


TECHNICAL BULLETIN


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









BOARD OF CONTROL

Frank M. Harris, Chairman, St. Petersburg
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
Mrs. Alfred I. duPont, Jacksonville
George W. English, Ji., Ft. Lauderdale
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee

EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President:,
J. Wayne Reitz, Ph.D., Provost for Agr.'
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Assistant Director
Rogers L. Bartley, B.S., Admin. Mgr.3
Geo. R. Freeman, B.S., Farm Superintendent

MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist 1
R. E. L. Greene, Ph.D., Agr. Economist 3
M. A. Brooker, Ph.D., Agr. Economist :
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
M. R. Godwin, Ph.D., Associate3
W. K. McPherson, M.S., Economist 3
Eric Thor, M.S., Asso. Agr. Economist :
J. L. Tennant, Ph.D., Agr. Economist
Cecil N. Smith, M.A., Asso. Agr. Economist
Levi A. Powell, Sr., M.S.A., Assistant
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agri. Economist
J. C. Townsend, Jr., B.S.A., Agricultural
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician 2
J. K. Lankford, B.S., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer 3
J. M. Myers, B.S., Asso. Agr. Engineer
J. S. Norton, M.S., Asst. Agr. Eng.

AGRONOMY
Fred H. Hull, Ph.D., Agronomist 1
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associa e
Darrel D. Morey, Ph.D., Associates
Fred A. Clark, M.S., Assistant2
Myron G. Grennell, B.S.A.E., Assistant
E. S. Horner, Ph.D., Assistant
A. T. Wallace, Ph.D., Assistant 3
D. E. McCloud, Ph.D., Assistant 3
G. C. Nutter, Ph.D., Asst. Agronomist

ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Hush.1 3
G. K. Davis, Ph.D., Animal Nutritionist 3
S. John Folks, Jr., M.S.A., Asst. An. Husb. 3
A. M. Pearson, Ph.D., Asso. An. Husb.3
John P. Feaster, Ph.D., Asst. An. Natri.
H. D. Wallace, Ph.D., Asst. An. Husb."
M. Koger, Ph.D., An. Husbandman 3
E. F. Johnston, M.S., Asst. An. Hus'i. '
J. F. Hentges, Jr., Ph.D., Asst. An. Husb. '
L. R. Arrington, Ph.D., Asst. Biochemist

DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.13
R. B. Becker, Ph.D., Dairy Husb.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.3
W. A. Krienke. M.S., Asso. Dairy Tech.3
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb. 3
Leon Mull, Ph.D., Asso. Dairy Tech. 3
H. H. Wilkowske, Ph.D., Asst. Dairy Tech. s
James M. Wing, M.S., Asst. Dairy IHub.


EDITORIAL
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Associa e Editor
L. Odell Griffith, B.A.J., Asst. Editors
J. N. Joiner, B.S.A., Assistant Editor
William G. Mitchell, A.B.J., Assistant Editor

ENTOMOLOGY "
A. N. Tissot, Ph.D., Entomologist'
L. C. Kuitert, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist
R. E. Waites, Ph.D., Asst. Entomologist

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

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist
F. S. Jamison, Ph.D., Horticulturist 34
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Horticulturist
V. F. Nettles, Ph.D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Horticulturist
R. D. D'ckey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. B. Hall, Ph.D., Asst. Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McFadden, Jr., Ph.D., Ass:. Hurt.
C. H. VanMiddelem, Ph.D., Asst. Biochemist
Buford D. Thompson, M.S.A., Ass Hort.
James Montelaro, Ph.D., Asst. Horticulturist
M. W. Hoover, M.S.A., Asst. Hort.

LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist1
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and
Botanist 3
Robert W. Earhart, Ph.D., Plant Path.2
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.
POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Husb.1 3
J. C. Driggers, Ph.D., Asso. Poultry Husb.

SOILS
F. B. Smith, Ph.D., Microbiologist '
Gaylord M. Volk, Ph.D., Soils Chemist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
Ralph G. Leighty, B.S., Asst. Soil Surveyor
G. D. Thornton, Ph.D., Asso. Microbiologist
Charles F. Eno, Ph.D., Asst. Soils Micro-
biologist
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwell, M.S.A., Asst. Chemist 4
V. W. Carlisle, B.S., Asst. Soil Surveyor
J. H. Walker, M.S.A., Asst. Soil Surveyor
S. N. Edson, M. S., Asst. Soil Surveyor a
William K. Robertson, Ph.D., Asst. Chemist
O. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D., Asst. Biochemist
J. G. A. Fiskel, Ph.D., Asst. Biochemist 3
L. C. Hammond, Ph.D., Asst. Soil Physicist 8
H. L. Breland, Ph.D., Asst. Soils Chem.

VETERINARY SCIENCE
D. A. Sanders, D.V.M.. Veterinarian 1 3
M. W. Emmel, D.V.M., Veterinarian 3
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist s
W. R. Dennis, D.V.M.. Asst. Parasitologist
E. W. Swarthout, D.V.M., Asso. Poultry
Pathologist (Dade City)








BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
W. C. Rhoades, Jr., M.S., Entomologist in
Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Jr., Ph.D., Soils Chemist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker, Jr., B.S., Asst. An. Husb.
T. E. Webb, B.S.A., Asst. Agronomist
Frank E. Guthrie, Ph.D., Asst. Entomologist
Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist
Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.D., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. IY. Leonard, Ph.D., Asso. Horticulturist
W. T. Long, M.S., Asst. Horticulturist
M. H. Muma, Ph.D., Asso. Entomologist
F. J. Reynolds, Ph.D., Asso. Hort.
W. F. Spencer, Ph.D., Asst. Chem.
I. H. Holtsberg, B.S.A., Asst. Ento.-Path.
K. G. Townsend, B, B.S.A., Asst. Ento.-th.
J. B. Weeks, B.S., Asst. Ento.-Path.
R. B. Johnson, Ph.D., Asst. Entomologist
W. F. Newhall, Ph.D., Asst. Biochem.
W. F. Grierson-Jackson, Ph.D., Asst. Chem.
Roger Patrick, Ph.D., Bacteriologist
Marion F. Oberachebar, Ph.D., Asst. Plant
Physiologist
Evert J. Elvin, B.S., Asst. Horticulturist

EVERGLADES STATION, BELLE GLADE
W. T. Forsee, Jr., Ph.D., Chemist in Charge
R. V. Allison, Ph.D., Fiber Technologist
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr.
R. W. Kidder, M.S., Asso. Animal Hush.
C. C. Seale, Associate Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. A. Wolf, M.S.. Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. G. Genung. B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman, Jr., M.S.A., Asst. An. Husb.
V. L. Guzman, Ph.D., Asst. Hort.
M. R. Bedsole, M.S.A., Asst. Chem.
J. C. Stephens, B.S., Drainage Engineer 2
A. E. Kretschmer, Jr., Ph.D., Asst. Soils
Chem.


SUB-TROPICAL STATION, HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. 0. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robert A. Conover, Ph.D., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Short.
J. C. Noonan, M.S., Asst. Hort.
M. H. Gallatin, B.S., Soil Conservationist

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
Marian W. Hazen, M.S., Animal Husband-
man in Charge 2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
H. W. Lundy, B.S.A., Associate Agronomist
W. R. Langford, Ph.D., Asst. Agronomist

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. A. Kelbert, Asso. Horticulturist
Robert 0. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Horticulturist
Amegda Jack, M.S., Asst. Soils Chemist


FIELD LABORATORIES

Watermelon, Grape, Pasture-Leesburg
J. M. Crall, Ph.D., Associate Plant Path-
ologist Acting in Charge
C. C. Helms, Jr., B.S., Asst. Agronomist
L. H. Stover, Assistant in Horticulture

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

Vegetables--Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
T. M. Dobrovsky, Ph.D., Asst. Entomologist

Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist 2
John R. Large, M.S., Asso. Plant Path.

Frost Forecasting-Lakeland
Warren O. Johnson, B.S., Meterologist in
Chg.

1 Head of Department
2 In cooperation with U. S.
3Cooperative, other divisions, U. of F.
4 On leave









Naringin, A Bitter Principle of Grapefruit

Occurrence, Properties and Possible Utilization
By
J. W. KESTERSON and R. HENDRICKSON1
INTRODUCTION
The bitter glucoside, naringin, found only in grapefruit (Citrus
paradisi (Macf.)) and in the shaddock or pummelo (Citrus
grandis (Linn.) Osbeck) further distinguishes these fruits from
the other species of citrus. Its occurrence as white aggregates
in the tissue of frozen grapefruit has undoubtedly been observed
by many in the citrus industry.
This glucoside is closely related to the nearly tasteless hes-
peridin of the sweet orange and to the bitter aurantamarin of
the sour orange. Much of the characteristic flavor of grapefruit
is due to this bitter constituent, which is considerably more bit-
ter than quinine. Naringin offers an excellent possibility for
development into a profitable by-product for the processor and
grower.
Several million pounds of naringin occur in the annual Florida
harvest of grapefruit but almost none is recovered for use. The
chemical industry has indicated that a potential market exists
for large tonnages of this glucoside and that the material may
bring a price that would make it a profitable by-product. Much
additional information is needed concerning the quantity of
naringin in Florida grapefruit and how the recovery of this
chemical can tie in with the present practices of handling and
processing citrus.
In spite of the profusion of literature, only meager data exist
concerning the distribution of naringin in the various compon-
ents of the fruit of different varieties of grapefruit. In this
work the authors have reported the results of broad scale sam-
pling to determine the naringin content with respect to variety
and season, and to size, weight and dry solids content of the fruit.
REVIEW OF LITERATURE
De Vry (9)2 in 1857 isolated a product from the flowers of
shaddock trees, native to the highlands of Java, which he mis-

1Associate Chemist and Assistant Chemist, Citrus Experiment Station,
Lake Alfred, Florida.
2 Figures in parentheses (Italic) refer to Literature Cited.









Naringin, A Bitter Principle of Grapefruit

Occurrence, Properties and Possible Utilization
By
J. W. KESTERSON and R. HENDRICKSON1
INTRODUCTION
The bitter glucoside, naringin, found only in grapefruit (Citrus
paradisi (Macf.)) and in the shaddock or pummelo (Citrus
grandis (Linn.) Osbeck) further distinguishes these fruits from
the other species of citrus. Its occurrence as white aggregates
in the tissue of frozen grapefruit has undoubtedly been observed
by many in the citrus industry.
This glucoside is closely related to the nearly tasteless hes-
peridin of the sweet orange and to the bitter aurantamarin of
the sour orange. Much of the characteristic flavor of grapefruit
is due to this bitter constituent, which is considerably more bit-
ter than quinine. Naringin offers an excellent possibility for
development into a profitable by-product for the processor and
grower.
Several million pounds of naringin occur in the annual Florida
harvest of grapefruit but almost none is recovered for use. The
chemical industry has indicated that a potential market exists
for large tonnages of this glucoside and that the material may
bring a price that would make it a profitable by-product. Much
additional information is needed concerning the quantity of
naringin in Florida grapefruit and how the recovery of this
chemical can tie in with the present practices of handling and
processing citrus.
In spite of the profusion of literature, only meager data exist
concerning the distribution of naringin in the various compon-
ents of the fruit of different varieties of grapefruit. In this
work the authors have reported the results of broad scale sam-
pling to determine the naringin content with respect to variety
and season, and to size, weight and dry solids content of the fruit.
REVIEW OF LITERATURE
De Vry (9)2 in 1857 isolated a product from the flowers of
shaddock trees, native to the highlands of Java, which he mis-

1Associate Chemist and Assistant Chemist, Citrus Experiment Station,
Lake Alfred, Florida.
2 Figures in parentheses (Italic) refer to Literature Cited.






Florida Agricultural Experiment Stations


took for hesperidin. Hoffman (17) pointed out that the com-
pound described by De Vry was not identical with the hesperidin
of Lebreton (19). To De Vry's compound, Hoffman assigned
the name aurantium. Sometime between 1876 and 1879 the
name naringin, derived from the sanskrit word for oranges, was
given to the compound that had been isolated and described as
hesperidin by De Vry.
The study of naringin as a compound different from hesperidin
and other similar glucosides was undertaken by Will (30) in
1885. He determined the best methods for the isolation and
purification of the compound.
Prior to the full understanding of the structure of naringin
Tutin (29) advanced the idea that naringenin, a hydrolytic
product of naringin, was a tetrahydroxy-chalcone and did not
contain an ester linkage. Asahina and Inubuse (4) concluded
from their experiments that naringenin was a flavanone which
was easily converted into the chalcone by rupture of the pyrone
ring. They were further of the opinion that naringenin oc-
curred in nature as a flavanone gulcoside linked with rhamnose
and glucose.
At the same time Asahina and Inubuse were attempting to
prove the structure of naringenin, Rosenmund and Rosenmund
(24) undertook the synthesis of this compound. These investi-
gators succeeded in breaking the naringenin by catalytic hydro-
genation to form phloretin, a hydrochalcone derivative, which
was in contradiction to statements by Asahina.
In 1928 Shinoda and Sato (27) claimed to have synthesized
naringenin by a method similar to that used by Rosenmund and
Rosenmund, employing phloroglucin and the ethyl carbonate of
p-coumaric acid in nitrobenzene and AIC13.
In a study of the naringin content of the rind of California
Marsh grapefruit, Harvey and Rygg (13) found that it decreased
in general through the growing season in all localities. How-
ever, the locality where the fruit was grown had a marked effect
on the change in naringin content while in cold storage. The
Corona and Fontana grapefruit peel decreased in naringin con-
tent during storage, the decrease being most pronounced at
32 F. and least at 520 F. In the Oasis fruit, the naringin in-
creased at all temperatures, most at 320 F. and least at 52 F.
California grapefruit was found by Poore (21) to contain
0.06% of naringin in the juice, 0.15% in the rag, 0.90% in peel
and 1.49% in the albedo. In general, the grapefruit residue







Naringin, A Bitter Principle of Grapefruit


consisting principally of peel, membrane and seeds, contained
about 0.75% naringin, the amount depending mainly upon the
ripeness of the fruit. The Florida fruit was found to contain
0.40% of naringin in the peel and 0.10% in the rag.
Zoller (33) found in fresh and old grapefruit the following
amounts of naringin: Indian River 0.080 and 0.048, Walters
0.073 and 0.034, and Marsh Seedless 0.066 and 0.014 percent,
calculated to the whole fruit. Fellers (10) also found that narin-
gin decreased in amount with maturity.
Rygg and Harvey (26) found that naringin in mature or
nearly mature grapefruit usually followed not a seasonal trend
but more nearly a temperature trend. They found more narin-
gin in grapefruit stored at 680 F. than at 380 F. It has been
suggested that the amount of glucoside in juice that has stood
for some time may increase and be one of the causes of its
bitter taste.
Hall (11), who investigated the glucosides, (he did not investi-
gate naringin), believed that the glucosides create, with the
sugars in the plants, a glucose-glucodise complex, which
may serve as a medium for translocation of the carbo-
hydrates synthesized in the chlorophyllous tissue. He advanced
the hypothesis that, in combination with the phenolic glucosides,
glucose forms a soluble, easily hydrolizable compound that is
thus temporarily withdrawn from the metabolism until it is
brought to that portion of the plant where it is stored or utilized.
Maurer et al. (20) found that the most significant change
in naringin content during the harvesting season occurred be-
tween October 13 and November 17 in 1948, in Texas grape-
fruit. During this period the naringin decreased on the aver-
age: 66% in the flavedo or outer layer of the peel; 60% in the
juice; 54% in the core; 53% in the section membranes; and
45 % in the albedo or inner layer of the peel. Those samples of
juice which contained more than 0.070% naringin possessed an
immature bitter taste. Grapefruit juice containing less than
0.050% naringin seemed to have a superior flavor that was
milder and more pleasing. Their tests failed to reveal any
change in naringin content during commercial processing.
It has been shown (25, 28) that vitamin P is present in citrus
fruits, such as lemon, orange and grapefruit. Although this
vitamin is generally believed to be a mixture of glucosides, hes-
peridin and eriodictin, it has never been isolated in pure form,
Lemon juice contains more vitamin P than does orange juice,















CONTENTS


Page

INTRODUCTION ...............-.... ... .. ..........-- ---.-- 5


REVIEW OF LITERATURE .---....-........ --------...... ..... --.----..------... 5


PHYSICAL AND CHEMICAL CHARACTERISTICS .......------------.-- ----------..... 8


EXPERIMENTAL PROCEDURE ....--..---.----...........-.. --.. --. ------------- 10


Collection of Samples ......-..........-- -----.--.. ---------- ......- .. 10


Methods of Analysis .-.. --........................... ----------- 13


EXPERIMENTAL RESULTS AND DISCUSSION --.......--......... ---------------..- 14


Naringin Content of Whole Grapefruit and Shaddock .............-........... 14


Naringin Content of Juice -.....-...-.........--.......... ----.. --.----- 23


Distribution of Naringin ........ -......---.--- ....-- ..- .... ----....------ -------. 23


Component Parts of Grapefruit and Shaddock Fruits -......... .... .......- 25


POSSIBLE UTILIZATION OF NARINGIN ...........---.--...--------- -------- 25


SUMMARY --..........-......-.. .....-.. .------- .... 26


LITERATURE CITED ....----............-- ...-------..... ---- ---- -- ------------- 27


APPENDIX ............. .- .... .. --.....- ..... --- ----.---.--......... 30






Florida Agricultural Experiment Stations


and this in turn more than grapefruit juice. The skin of these
fruits is generally richer in vitamin P than the juice or the pulp.
The analytical methods available to these early workers left
much to be desired and probably accounts for the lack of more
extensive information on naringin in the literature. However,
during the past five years the more convenient and reliable
method of Davis (8) has been available for naringin studies.
Methods of recovering naringin (5, 15, 16) from grapefruit
peel have been investigated but little has been done to develop
the chemical as a by-product.

PHYSICAL AND CHEMICAL CHARACTERISTICS
Besides the intense bitterness of naringin, one part in 50,000
being detectable by taste, many other characteristics serve to
identify it. When dried at 1100 C. it has a melting point of
171 C. and has the composition of C27H32014.2H20 (2). Re-
crystallized from water, it has six additional waters of crystal-
lization and melting point of 83 C. Its structural formula
(2, 32) has been confirmed as being:


HCOH 'OunHCH I |OIH
0 HC H HOC O L
H HH 0
j uH nu H(C OH T / C2

CH3 H2 H
(Rhamnose) (Glucose) (Naringenin)

The picture of the naringin crystals (magnified 40 X) on the
cover page illustrates its appearance when recrystallized from
water. The needles making up the rosette pattern are easily
broken apart and have been found to have the following refrac-
tive index (18), as determined by the immersion method:
- = 1.480 (lengthwise), P = 1.625 and y = 1.668. It has a specific
rotation of [ ] 19 = -82' in alcohol. Naringin is insoluble
in ether, chloroform, benzene and ligroin; yet is soluble to a
varying degree in water, alcohol, acetone, glacial acetic acid and
pyridine. Calcium hydroxide, as well as other alkalis, greatly
increases the solubility of naringin in water and is the basis for
a patent on the recovery of naringin from grapefruit peel (16).
Further data on its solubility are shown in Table 1.







Naringin, A Bitter Principle of Grapefruit


TABLE 1.--SOLUBILITY OF NARINGIN IN VARIOUS SOLVENTS AT DIFFERENT
TEMPERATURES.

Temperature Solvent Solubility
C. I Percent by Vclume

6 .02
35 .08
45 Water (22) .20
55 .72
65 4.2
75 10.8

5 3.3
21 Ethyl Alcohol 95% I 4.2
39 6.5

21 3.0
Glacial Acetic Acid
39 5.2


Ferric chloride interacts with minute quantities of naringin,
producing a vinaceous red color that has been used for quantita-
tive colorimetric determinations (12). This procedure is handi-
capped by interference from other hydroxy compounds and
citric acid. With higher concentrations of naringin an almost
black color will develop. This color can be used to show pictorially
the physical location of naringin in grapefruit, as illustrated in
Fig. 2. The yellow coloration that develops when sodium hydrox-
ide is added to a naringin solution is the basis of a more specific
and reliable colorimetric method (8). The color of flavanone
glycosides in hydrochloric acid solution and alkali after reduction
is helpful in distinguishing naringin from other flavanones (3).
Solutions of naringin in low concentration markedly increase
in viscosity in the presence of alkali and a di- or tri-valent cation.
The pH of the solution appears to be a critical factor, as shown
in Fig. 3, wherein the viscosity of a dilute solution is shown in
relation to pH.
By refluxing naringin for a few hours in the presence of a
dilute mineral acid it can be hydrolyzed to one mole each of
naringenin, rhamnose and glucose. Naringenin melts at 2480 C.
with decomposition and can be synthesized from phloroglucinol
and carbethoxy-p-coumaryl chloride, and aluminum chloride
(27). Its triacetyl derivative (m.p. 53.50 C.) is prepared from
glacial acetic acid and concentrated sulfuric acid (4).







Florida Agricultural Experiment Stations


Fig. 2.-Grapefruit showing the location of naringin by the addition of ferric
chloride to the cut surface.

EXPERIMENTAL PROCEDURE
Collection of Samples.-In studying the naringin content of
grapefruit the more common types of this fruit, such as Duncan,
Marsh, Thompson, Foster and Ruby Red, were included. Their
genetic relationship is given in Fig. 4. It has been commonly
accepted, but not established, that the grapefruit was a sport
from the shaddock, because of the resemblance of the two. It
is possible, however, that the two may not be related, or that
the grapefruit may be a natural cross between shaddock and
orange.
Samples of fruit were picked once each month at random from
each of the following positions on the tree; a total of 16 fruits
were required for each sample.







Florida Agricultural Experiment Stations


Fig. 2.-Grapefruit showing the location of naringin by the addition of ferric
chloride to the cut surface.

EXPERIMENTAL PROCEDURE
Collection of Samples.-In studying the naringin content of
grapefruit the more common types of this fruit, such as Duncan,
Marsh, Thompson, Foster and Ruby Red, were included. Their
genetic relationship is given in Fig. 4. It has been commonly
accepted, but not established, that the grapefruit was a sport
from the shaddock, because of the resemblance of the two. It
is possible, however, that the two may not be related, or that
the grapefruit may be a natural cross between shaddock and
orange.
Samples of fruit were picked once each month at random from
each of the following positions on the tree; a total of 16 fruits
were required for each sample.







Naringin, A Bitter Principle of Grapefruit


2,00i


200


100


6.0 7.0 8.0 9.0 10.0 11.0 12.0
PH
Fig. 3.-Viscosity of naringin solutions at 32 C. in relation to pH. Sam-
ples made alkaline initially with calcium hydroxide and back titrated with
citric acid.








Florida Agricultural Experiment Stations


East West North South
Top inside Top inside Top inside Top inside
Top outside Top outside Top outside Top outside
Bottom inside Bottom inside Bottom inside Bottom inside
Bottom outside Bottom outside Bottom outside Bottom outside
As the fruit increased in size, it was found necessary to reduce
the number per sample. In these samples one fruit was taken
from each of the cardinal points from both the top and the bot-


Fig. 4.-Genetic Relationship of the Common Types of Grapefruit.


THOMPSON PINK VARIETY
Sport of Marsh Seedless







Naringin, A Bitter Principle of Grapefruit


tom of the tree to give a total of eight. Fruits for all the va-
rieties studied were taken from trees on rough lemon rootstock
that had been on the standard cultural and spray practices as
recommended by the Experiment Station. This was done to
eliminate any differences due to these variables.
Methods of Analyses.-The grapefruit samples were analyzed
on a whole fruit basis or separated into the component parts-
juice, rag and pulp, flavedo and albedo-depending on whether
the fruit were mature enough to give a moderate juice yield.
The procedure for analyzing the small whole fruit was first to
determine its average diameter and weight, after which it was
coarsely ground in a universal food chopper. The ground sample
was thoroughly mixed and a 100 gram representative sample
weighed directly into a Waring Blendor.
The peel was more finely comminuted in the blendor with
100-150 ml. of 95 percent alcohol which facilitated the grinding
and extraction. One minute of grinding was usually more than
sufficient to comminute it to a fine uniform mass. This was then,
washed into a beaker with 95% ethyl alcohol, giving a total
volume of 500 ml. (including the previous 100-150 ml.). The
finely chopped peel was allowed to stand in intimate contact
with the alcohol for at least 16 hours with occasional stirring.
If necessary, the sample could be conveniently held at this point
until the extraction was completed. The extracting alcohol was
separated by draining it through two layers of cheesecloth and
squeezing out most of the remaining alcohol by hand.
The pressed peel was further extracted by adding 500 ml. of
water and one gram of dry C. P. calcium oxide which was well
mixed and allowed to stand two hours. This alkaline extract
was then drained and squeezed out in similar fashion to the
alcohol extraction. A third extraction was carried out by add-
ing 500 ml. of water to the pressed peel and heating to 950 C.
immediately. After cooling and standing for two hours it was
drained and pressed. The three portions of extracting liquor
were combined, made to exactly 1,500 ml. and an aliquot diluted
for analytical purposes.
When other than whole fruit was analyzed the procedure was
as follows: The flavedo was cut apart from the fruit by means
of a potato peeler. Then the fruit was halved and juiced by
means of a citrus juice extractor. The juice was strained
through one layer of cheesecloth and analyzed directly. The
residue was separated into albedo, rag and pulp, and seeds. This






Florida Agricultural Experiment Stations


was accomplished by manually separating the seeds and pulling
the rag and pulp apart from the albedo. Each of the separated
portions was weighed. When it was desired to analyze a
particular portion, it was ground and extracted as described
for whole fruit.
Extracts of the whole fruit or parts thereof were analyzed
for naringin by the following adaptation of the Davis method (8).
A 0.5 ml. aliquot of the diluted extract or juice was added to
24 ml. of 90 percent diethylene glycol and mixed. Thereafter
0.5 ml. of approximately 4 N sodium hydroxide was added and
mixed. The increase in color was read after 10 minutes in a
Fisher Electrophotometer using a 425 mu blue filter. The
development and reading of the color was made at approximately
250 C. and compared against a standard curve to determine
percent by volume of naringin.

EXPERIMENTAL RESULTS AND DISCUSSION
Naringin Content of Whole Grapefruit and Shaddock.-In this
study of glucoside content of grapefruit, the physical dimen-
sions, wet and dry weight of the fruit, as well as the naringin
content, are recorded for Duncan, Marsh, Foster, Thompson
and Ruby Red and for shaddock (Thong Dee), as shown in
Tables 2 through 7.
From these tables it can be seen that the quantity of naringin
per fruit increased until the grapefruit reached an equatorial
diameter of about two inches. It then became fairly constant,
based on quantity per fruit, for the remainder of the fruit
season. Contrary to the findings of previous writers (10, 13,
20), there was no decrease in total quantity of naringin present.
However, due to the increase in size and weight of the fruit,
the percent naringin decreased. When the glucoside content
of the grapefruit and shaddock was compared against its wet
and dry weight, there was a decrease in the percent of naringin,
as shown in Fig. 5. Duncan grapefruit was used to demonstrate
this point and is typical of the other varieties.
The physiological importance of naringin cannot be taken
lightly in view of the high concentration (10 to 20 percent)
found in small fruit one-half inch in diameter; nor can it be
considered to be a metabolic end product when, on a dry weight
basis, naringin content amounts to as much as 40 to 75 percent
of the small fruit. The biological function of naringin, though
not clearly established, would appear to be an important one.






Florida Agricultural Experiment Stations


was accomplished by manually separating the seeds and pulling
the rag and pulp apart from the albedo. Each of the separated
portions was weighed. When it was desired to analyze a
particular portion, it was ground and extracted as described
for whole fruit.
Extracts of the whole fruit or parts thereof were analyzed
for naringin by the following adaptation of the Davis method (8).
A 0.5 ml. aliquot of the diluted extract or juice was added to
24 ml. of 90 percent diethylene glycol and mixed. Thereafter
0.5 ml. of approximately 4 N sodium hydroxide was added and
mixed. The increase in color was read after 10 minutes in a
Fisher Electrophotometer using a 425 mu blue filter. The
development and reading of the color was made at approximately
250 C. and compared against a standard curve to determine
percent by volume of naringin.

EXPERIMENTAL RESULTS AND DISCUSSION
Naringin Content of Whole Grapefruit and Shaddock.-In this
study of glucoside content of grapefruit, the physical dimen-
sions, wet and dry weight of the fruit, as well as the naringin
content, are recorded for Duncan, Marsh, Foster, Thompson
and Ruby Red and for shaddock (Thong Dee), as shown in
Tables 2 through 7.
From these tables it can be seen that the quantity of naringin
per fruit increased until the grapefruit reached an equatorial
diameter of about two inches. It then became fairly constant,
based on quantity per fruit, for the remainder of the fruit
season. Contrary to the findings of previous writers (10, 13,
20), there was no decrease in total quantity of naringin present.
However, due to the increase in size and weight of the fruit,
the percent naringin decreased. When the glucoside content
of the grapefruit and shaddock was compared against its wet
and dry weight, there was a decrease in the percent of naringin,
as shown in Fig. 5. Duncan grapefruit was used to demonstrate
this point and is typical of the other varieties.
The physiological importance of naringin cannot be taken
lightly in view of the high concentration (10 to 20 percent)
found in small fruit one-half inch in diameter; nor can it be
considered to be a metabolic end product when, on a dry weight
basis, naringin content amounts to as much as 40 to 75 percent
of the small fruit. The biological function of naringin, though
not clearly established, would appear to be an important one.












TABLE 2.-MONTHLY VARIATON IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF DUNCAN GRAPEFRUIT.*


Blk. VII

ii Whole Fruit _
Date I Glucoside I
I Diameter Wet Wt. Dry Wt. Content I
S in. Gms. Gms. Gms. I

4-28-52 .. 0.50 1.52 0.33 0.25 II
5-1-51 ... 1.2 14 4.3 1.4 I
6-1-51 .... 2.3 76 16 2.4 I
7-1-51 .... 3.3 184 32 2.6
8-1-51 .... 3.7 306 48 2.8 II
9-1-51 .... 3.8 377 57 2.1
10-1-51 .... 4.2 500 76 2.6
11-1-51 .... 4.5 577 92 2.5
12-1-51 .... 4.6 619 102 2.6 I
1-1-52 .... 4.7 670 108 3.0 I
2-1-52 .... 4.8 742 125 3.1 II
3-1-52 .... 4.6 666 119 2.6
4-1-52 .... 4.8 721 112 2.5 I
II I
Average value for either 8 or 16 fruit.


Row E


Brix






8.4
8.9
9.8
10.5
10.4
10.3
11.6
10.5


Juice
Glucoside
Acid Content
/ by Vol. I




-i
1.9 0.031
1.6 0.024
1.7 0.028
1.8 0.032
1.5 0.036
1.6 0.030
1.7 0.022
1.4 0.016


Tree 2


Distribution of Glucoside--%

Juice Albedo Flavedo IRag
and Pulp
I-"














TABLE 3.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF MARSH GRAPEFRUIT.*


Blk. II


Row 19


Tree 7


II I
[i Whole Fruit Ij
Date I I Glucoside I1
1 Diameter WetWt. Dry Wt. Content I "Brix
S in. Gms. Gms. I Gms. I


0.53 1.4 0.3 0.2 -
0.95 9.0 2.3 0.8 -
2.0 44 11 1.6 -
2.6 111 20 1.6 -
2.9 178 28 1.7 [ -
3.6 295 40 2.2 8.2
3.7 339 43 1.7 8.3
3.9 419 55 1.8 I 8.8
4.1 466 60 1.8 8.9
4.3 550 67 2.1 8.5
4.5 584 74 2.2 8.7
4.3 552 69 1.7 8.7
4.4 578 68 1.7 I8.4
1 II ___


Juice
Glucoside I
Acid Content
% % by Vol.
-




1.9 0.029
1.6 0.031
1.5 0.035
1.6 0.029
1.4 0.028
1.3 0.030
1.4 0.024
1.3 0.019


Distribution of Glucoside-%


Juice


Albedo Flavedo Rag
land Pulp





53.5 7.2 38.2
57.4 10.4 29.8
57.4 8.9 30.2
55.3 7.1 34.5
56.9 7.2 32.8
55.2 6.3 34.5
58.3 5.6 32.9
57.3 5.4 34.4


4-11-52 _
5-1-51 .
6-1-51 ....
7-1-51 ....
8-1-51 ....
9-1-51 ....
10-1-51 ...
11-1-51 ....
12-1-51 ...
1-1-52 ..-
2-1-52 ....
3-1-52 ....
4-1-52 ....


* Average value for either 8 or 16 fruit.











TABLE 4.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF FOSTER GRAPEFRUIT.*


Blk. XX

|I Whole Fruit !
Date I Glucoside I
I Diameter Wet Wt. IDry Wt. Content II Brix
Ii in. Gms. Gms. Gms. ]

4-21-52 I 0.54 1.5 0.5 0.2
5-1-51 .... 1.1 12 3.2 1.4
6-1-51 ... 2.5 82 17 2.7 -
7-1-51 -.. 1 3.3 211 36 3.1 -
8-1-51 -.. 3.8 347 52 3.1 I
9-1-51 .... 4.0 442 67 3.2 8.0
10-1-51 .... 4.5 562 79 3.1 8.3
11-1-51 .... 4.6 641 91 3.1 II 8.6
12-1-51 -.... i 4.8 709 102 3.6 1 8.5
1-1-52 ....- 4.9 769 106 3.5 I 8.9
2-1-52 .... 5.0 800 109 3.6 8.7
3-1-52 .... 4.9 781 112 3.4 9.2
4-1-52 ... 5.1 859 122 I 3.4 I1 9.5

Average value for either 8 or 16 fruit.


Row G

Juice [
Glucoside II
Acid Content
% / by Vol.





1.7 0.031
1.4 0.016
1.3 0.026
1.3 0.029
1.2 0.035
1.2 0.033
1.2 0.037
1.2 0.015
I II


Tree 10


Distribution of Glucoside--

Juice Albedo Flavedo Rag
and Pulp




| ---
1.0 54.9 8.5 35.6
0.8 58.3 7.2 33.7
2.1 59.4 7.0 31.5
2.3 63.6 7.4 26.7
3.2 62.7 4.3 29.8
3.0 60.4 5.0 31.6
3.8 61.4 4.4 30.4
1.6 57.8 4.4 36.2














TABLE 5.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF THOMPSON GRAPEFRUIT.*


Blk. I


Whole Fruit


Date II I Glucoside )1
Diameter Wet Wt. Dry Wt. Content Ii
II in. Gms. Gms. Gms. ii


oBrix
1


Row I

Juice


Glucosider
Acid Content
% I % by Vol.


4-18-52 .. 0.53 1.4 0.5
5-1-51 .... 1.05 10 2.5
6-1-51 .... 2.1 51 11
7-1-51 .... 2.7 122 22
8-1-51 .... 3.0 181 27
9-1-51 .... 3.3 254 36
0-1-51 .... 3.5 320 43
11-1-51 .... 3.8 375 50
12-1-51 .... 3.9 409 53
1-1-52 ... 3.9 421 55
2-1-52 .... 4.1 459 60
3-1-52 .... 4.2 497 64
4-1-52 .... 4.2 495 62

Average value for either 8 or 16 fruit.


0.028
0.035
0.037
0.029
0.023
0.019
0.020
0.017


Tree 37


Distribution of Glucoside-%


i i
11 Juice


I I
Albedo IFlavedo I Rag
SI and Pulp


-




9.1
9.8
8.0
8.7
6.0
7.0
6.0
5.6


Whole~ Fri


ii ....... ......


'


II


-------~--~-~-~-~-











TABLE 6.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF RUBY RED GRAPEFRUIT.*
Blk. XX Row N Tree 9


I Whole Fruit Juic
Date IGlucoside
IDiameter Wet Wt. Dry Wt. Content Brix Acid
S in. Gms. Gms. Gms. %_

4-28-52 0.50 1.4 0.4 0.2 -
5-1-51 ... 1.1 13 3.1 1.1 -
6-1-51 .... 2.2 63 14 2.0 -
7-1-51 .... 2.8 131 22 2.0 --
8-1-51 .... 3.2 208 30 2.2 -
9-1-51 .... 3.4 270 36 2.0 I 7.5 1.6
10-1-51 .... 3.7 351 43 2.3 I 7.7 1.3
11-1-51 .... 3.8 376 47 2.1 8.0 1.2
12-1-51 .... 4.1 456 56 2.4 II 8.1 1.2
1-1-52 .... 4.1 475 57 2.4 I 8.0 1.0
2-1-52 .... 4.4 572 65 2.4 I7.6 1.0
3-1-52 .... 4.3 530 62 2.4 7.7 1.0
4-1-52 .... 4.4 580 66 2.5 ii 7.5 0.9
Average value for either or 16 fruit.
Average value for either 8 or 16 fruit.


e


Distribution of Glucoside-%


Glucoside II
Content [ Juice
% by Vol. I


0.019
0.027
0.030
0.027
0.021
0.018
0.016
0.016


0.9
1.6
2.6
2.5
2.0
2.1
1.6
1.8


Albedo Flavedo






50.3 9.2
57.8 9.9
53.0 12.4
60.9 7.6
62.7 6.7
61.6 6.0
62.9 4.6
65.6 5.5


Rag
and Pulp





39.6
30.7
32.0
29.0
28.6
30.3
30.9
27.1


0.9
1.6
2.6
2.5
2.0
2.1
1.6
1.8














TABLE 7.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF SHADDOCK (THONG DEE).*


Blk. III

|I Whole Fruit I
Date I I Glucoside i
SDiameter I Wet Wt. Dry Wt. I Content I Brix
I in. Gmis. Gms. Gms. i
II I I
4-11-52 .. 0.70 3.1 0.8 0.4 -
5-1-51 ... I 1.65 35 7.8 2.4
6-1-51 .... 3.5 202 44 4.7
7-1-51 ... II 5.1 534 109 6.2
8-1-51 .. 5.5 834 153 6.2 -
9-1-51 ... 5.8 1056 189 4.6 10.5
10-1-51 .... 6.3 1473 244 5.7 10.1
11-1-51 .... 6.8 1745 290 6.4 10.6
12-1-51 .... 6.7 1755 296 6.9 10.2
1-1-52 .... I 7.0 1975 323 6.6 10.8
2-1-52 .... 1 7.1 2077 339 6.8 10.4
3-1-52 .... 7.1 2060 328 6.0 1 10.4
4-1-52 .... I 7.0 1940 344 6.7 I 11.3

Average value for either 4 or 8 fruit.


Row B


Tree 14


Juice I\
I Glucoside 11
Acid Content II
% 1% by Vol. |

I



1.2 0.021
1.0 0.016
1.2 0.019
1.2 0.036
1.3 0.025
1.4 0.025 1
1.4 0.021
1.4 0.022
II


Distribution of Glucoside-%


Juice Albedo Flavedo






0.7 48.3 5.9
0.7 62.9 4.9
1.1 52.3 13.0
2.4 43.2 21.4
2.2 55.3 13.3
2.6 53.2 12.3
2.0 49.1 12.8
1.7 50.6 13.8


Rag
and Pulp





45.1
31.5
33.6
33.0
29.2
31.9
36.1
33.9







Naringin, A Bitter Principle of Grapefruit


100
80- DUNCAN GRAPEFRUIT
60

40-



20- 0 Whole Fruit
Dry Weight

10
8
6

4
z
0.
z



1.0
0.8-
0.6

0.4-



0.2


0 .1 i I i I I
A M J J A S N D J F M A
1951-52 SEASON
Fig. 5.-Naringin content on a dry and whole-fruit basis for Duncan
grapefruit.

The total naringin content for the different varieties estab-
lished shaddock as having the highest content and Thompson
the lowest on a whole-fruit basis, as shown in Fig. 6. The range
in glucoside content varied from 6.2 to 1.8 grams per fruit.
If the varieties are arranged in order of decreasing naringin







Florida Agricultural Experiment Stations


content on a per-fruit basis, the following order is observed:
Shaddock, Foster, Duncan, Ruby Red, Marsh and Thompson.
This order would then indicate that the glucoside content is very
closely related to the total weight of the fruit. In other words,
the larger sized fruit will contain the larger quantity of narin-


-6.0
cr
LU.

m 5.0
a.
z
D4.0
z

z



ac
30
U)


NARINGIN CONTENT



o Duncan
4< Marsh
Foster
e Ruby
Thompson
A Shaddock


I


c-.ur


Sn


I I I Il I


M J J A SO N D J
1951-52 SEASON


F MA


Fig. 6.-Naringin content on a per-fruit basis for five varieties of grapefruit
and Thong Dee shaddock.


I







Naringin, A Bitter Principle of Grapefruit 23

gin. However, the percent naringin on a dry or whole-fruit basis
shows Ruby Red to be the highest and shaddock the lowest.
No significant order could be assigned to the other four varieties.
Naringin Content of Juice.-In expectation that the naringin
content of grapefruit juice would in some way correlate with
the maturity of the fruit, the degree Brix, percent acid and
percent naringin by volume were determined, and are presented
in Tables 2 through 7. Degree Brix was determined by re-
fractometer at 28 C. and percent acid by titration with alkali,
using the standard method of the citrus industry.
The possibility of using naringin content as a measure of
maturity was previously investigated by Baier (6) and Wood
and Reed (31) without much success. However, later work by
Maurer et al. (20), who felt earlier work suffered because of
the analytical methods available, showed significant decreases
in percent naringin as the fruit became more mature. In Texas
the percent naringin in the juice of all grapefruit varieties ap-
peared to decrease consistently as the season progressed. This
observation was not borne out by the grapefruit varieties studied
in Florida. The Florida grapefruit had considerably passed
peak maturity before a significant decrease developed. This
change occurred during April. Neither Brix, percent acid nor
ratio could be correlated with the percent naringin in the juice
or its distribution in the fruit. The percent naringin in the
juice of the grapefruit varieties investigated was found to be
within the limits of 0.02 to 0.03 percent throughout the entire
season.
It was noticed that the increase in degree Brix from Septem-
ber to April was rather small. More significant changes might
be anticipated by use of a larger sample. The percent acid
gradually decreased for all varieties except shaddock, in which
case the percent acid increased.
Distribution of Naringin.-It is shown in Tables 2 through 7
that almost 90 percent of the naringin is concentrated in the
albedo, rag and pulp for all varieties studied. This was in ex-
cellent agreement with Braverman (7), who described the prin-
cipal location of the glucosides to be in the carpellary membrane,
at the boundary between the juice segments and albedo. Since
this was the case, attempts to obtain higher juice yields by in-
creased pressure or deeper burring by juice extractors would
tend to increase the naringin content of the juice (14).
The hand juice extractor used in this study folded and squeezed







Naringin, A Bitter Principle of Grapefruit 23

gin. However, the percent naringin on a dry or whole-fruit basis
shows Ruby Red to be the highest and shaddock the lowest.
No significant order could be assigned to the other four varieties.
Naringin Content of Juice.-In expectation that the naringin
content of grapefruit juice would in some way correlate with
the maturity of the fruit, the degree Brix, percent acid and
percent naringin by volume were determined, and are presented
in Tables 2 through 7. Degree Brix was determined by re-
fractometer at 28 C. and percent acid by titration with alkali,
using the standard method of the citrus industry.
The possibility of using naringin content as a measure of
maturity was previously investigated by Baier (6) and Wood
and Reed (31) without much success. However, later work by
Maurer et al. (20), who felt earlier work suffered because of
the analytical methods available, showed significant decreases
in percent naringin as the fruit became more mature. In Texas
the percent naringin in the juice of all grapefruit varieties ap-
peared to decrease consistently as the season progressed. This
observation was not borne out by the grapefruit varieties studied
in Florida. The Florida grapefruit had considerably passed
peak maturity before a significant decrease developed. This
change occurred during April. Neither Brix, percent acid nor
ratio could be correlated with the percent naringin in the juice
or its distribution in the fruit. The percent naringin in the
juice of the grapefruit varieties investigated was found to be
within the limits of 0.02 to 0.03 percent throughout the entire
season.
It was noticed that the increase in degree Brix from Septem-
ber to April was rather small. More significant changes might
be anticipated by use of a larger sample. The percent acid
gradually decreased for all varieties except shaddock, in which
case the percent acid increased.
Distribution of Naringin.-It is shown in Tables 2 through 7
that almost 90 percent of the naringin is concentrated in the
albedo, rag and pulp for all varieties studied. This was in ex-
cellent agreement with Braverman (7), who described the prin-
cipal location of the glucosides to be in the carpellary membrane,
at the boundary between the juice segments and albedo. Since
this was the case, attempts to obtain higher juice yields by in-
creased pressure or deeper burring by juice extractors would
tend to increase the naringin content of the juice (14).
The hand juice extractor used in this study folded and squeezed







Florida Agricultural Experiment Stations


a half grapefruit and required only a moderate amount of pres-
sure to extract the juice. The juice extracted under these con-
ditions was found to contain an average of 1 to 3 percent of

100

DUNCAN GRAPEFRUIT
80


60

Cr



0





















i.-
n,-
20 o Albedo
W 1 Rag a Pulp
o Flavedo
Sagrp Juice
5
O

z



S6-

z
u- 4-
O











S O N D J F M A
1951-52 SEASON
Fig. 7.-Distribution of naringin in the component parts of Duncan
grapefruit.







Naringin, A Bitter Principle of Grapefruit


the total naringin for all grapefruit varieties. Those juice sam-
ples with the highest juice yield contained the highest percent
of glucoside.
The distribution of naringin curves being similar for the
varieties, Duncan grapefruit was used to show the overall
changes in the distribution of naringin (Fig. 7). This graph-
ically illustrated that time of season was not a variable which
influenced the distribution of the glucoside. The one exception
was a consistent, but small, decrease in the naringin content
of the flavedo, in all the samples except shaddock. The dis-
tribution of naringin in the component parts of grapefruit and
shaddock as the fruits approach and pass maturity would in
most cases be as follows: juice 1 to 3 percent, albedo 50 to 60
percent, flavedo 5 to 10 percent, rag and pulp 30 to 40 percent.
Component Parts of Grapefruit and Shaddock Fruits.-In this
survey it was found necessary to determine the proportion of
each component part making up the whole fruit and the dry
solids content of each component. These data, obtained for
several varieties, are included in Tables 8 through 13 in the ap-
pendix. On the basis of these tables the range in percentage
of the component parts of grapefruit and shaddock was as fol-
lows: juice 14 to 55 percent, albedo 16 to 37 percent, seeds 0.5
to 6.0 percent. The albedo and flavedo remained at a fairly
uniform percentage, while increased or decreased juice content
was at the expense of the rag and pulp.
The range in dry solids content of the components of grape-
fruit and shaddock was: juice 8 to 12 percent, albedo 15 to 22
percent, flavedo 19 to 29 percent, rag and pulp 12 to 18 percent,
seeds 30 to 68 percent.

POSSIBLE UTILIZATION OF NARINGIN
Since naringin yields naringenin, glucose and rhamnose upon
hydrolysis, Pulley and von Loesecke (23) believed that naringin
recovered from citrus waste could be a source material for the
preparation of rhamnose. In their work they describe a method
for preparing rhamnose from naringin. They obtained yields
of this sugar amounting to about 20% of the naringin taken,
or approximately 62% of the theoretical.
The bitter taste of grapefruit, which is imparted by naringin.
has been used to advantage in the preparation of beverage
drinks. Naringin may also be used to enhance the piquant
flavor of high-class confections, especially those flavored with







Florida Agricultural Experiment Stations


citrus fruit flavors. Being harmless, the bitter principle from
grapefruit makes a suitable bitters for these purposes. It is
sold commercially under the name "Amerin".
Naringenin, the product obtained by the acid hydrolysis of
naringin, may be further hydrolyzed by potassium hydroxide
to yield p-coumaric acid and phloroglucin. These compounds
in turn may be used for the synthesis of other organic chemicals.
The authors have been successful in producing dyes by using
naringin as an intermediate. The particular dyes are acid azo
dyes produced by coupling various diazo compounds into narin-
gin. This flavanone glucoside appears to be an excellent dye
intermediate having considerable possibilities, and the diazos
of sulfanilic acid, p-nitro-aniline, etc., have been coupled into
this glucoside to form yellow-red dyes that are quite bright
and pleasing in color. The application of these water-soluble
dyes is presently limited to wool and silk. However, there has
been some recent interest in these dyes for a newer type wood
stain that has exceptional light-fast properties.
Naringin is related to hesperidin and other flavanones known
to have therapeutic action. In 1936 Rusznyak and Szent-
Gyorgyi (25) announced that they had found indications of a
nutritional factor that influenced capillary permeability, and
which activated vitamin C. This substance, which they called
vitamin P, could be obtained from citrus fruits and red peppers.
At present there still exists some controversy as to whether
vitamin P can properly be classified as a vitamin. While it is
thought to be a mixture of hesperidin and eriodictin, little is
known of its physiological role in animal metabolism. Other
flavanones have been found to be effective for similar thera-
peutic uses and in some cases naringin, or naringenin, has shown
greater physiological activity than hesperidin (1). It seems
quite possible, therefore, that the chemical similarity between
naringin and the components of vitamin P will be used to better
advantage, especially so in light of its better solubility.

SUMMARY
An investigation of the glucoside content of grapefruit and
shaddock led to the following conclusions:
The quantity of naringin in grapefruit and shaddock fruit
was found to remain constant once the fruit had grown to two
inches in equatorial diameter. Thereafter, as the fruit grew
larger, the naringin content on a percentage basis became lower.







Naringin, A Bitter Principle of Grapefruit


The glucoside content varied from 6.2 to 1.8 grams per fruit,
with shaddock having the most and Thompson grapefruit the
least. On a percent by weight basis, Ruby Red grapefruit con-
tained the highest percentage of naringin.
The unusually high naringin content of 40 to 75 percent on
a dry-weight basis in small fruit indicates that its physiological
function may be important although this has not been investi-
gated.
The percent by volume of naringin in the juice could not be
correlated with fruit maturity. It was found to vary between
the limits of 0.02 and 0.03 percent throughout the entire season.
Almost 90 percent of the total naringin present in grapefruit
and shaddock was found in the albedo, rag and pulp.
Analyses of the component parts of the fruit established that
the albedo and flavedo accounted for a uniform percent of the
fruit, while juice content increased or decreased at the expense
of the rag and pulp.
The range in the moisture content of the component parts,
the distribution of naringin in the component parts, and per-
centage of the component parts comprising the whole fruit was
determined for five varieties of grapefruit and Thong Dee
shaddock.
Possible uses for naringin as a fine organic chemical include
the preparation of acid azo dyes and wood stains, vitamin P,
rhamnose, p-coumaric acid and phloroglucin. It is also used to
enhance the piquant flavor of confections and beverages.

LITERATURE CITED
1. ARMENTANO, L. The effect of flavone dyes on blood pressure. Feit.
ges. Experimentelle Medizin. 102: 219. 1938.
2. ASAHINA, Y., and M. INUBUSE. On the flavanone glucosides. IV
Naringin and hesperidin. J. Pharm. Soc. Japan 49: 128-34. 1929.
3. ASAHINA, Y., and M. INUBUSE. On the flavanone glucosides. V
Reduction of flavone and flavanone derivatives. Ber. 62B: 3016-21.
1929.
4. ASAHINA, Y., and M. INUBUSE. Flavanone glucosides II. Constitu-
tion of naringenin. Ber. 61B: 1514-6. 1928.
5. BAIER, W. E. Methods for recovery of naringin. U. S. Patent No.
2,421,063. May 27, 1947.
6. BAIER, W. E. Maturity studies of California and Arizona Marsh
grapefruit. Calif. Citrograph 17: 94. 1932.
7. BRAVERMAN, J. B. S. Citrus products. Chemical compositions and
chemical technology. 424 pp. 1949. Interscience Publishers, Inc.







28 Florida Agricultural Experiment Stations

8. DAVIS, W. B. Determination of flavanones in citrus fruits. Anal.
Chem. 19: 476-8. 1947.
9. DEVRY, F. Hesperidin. Jahres. Bericht. fur Pharmakognos. 132.
1866.
10. FELLERS, CARL R. The grapefruit and its juice. Glass Packer 2:
509-10. 1929.
11. HALL, J. A. Glucosides of the Navel orange. J. Amer. Chem. Soc.
47: 1191-1195. 1925.
12. HARVEY, E. M. Colorimetric determination of naringin. Plant Physiol.
11: 463-5. 1936.
13. HARVEY, E. M., and G. L. RYGG. Field and storage studies on changes
in the composition of the rind of the Marsh grapefruit in Cali-
fornia. J. Agr. Research. 52: 747-87. 1936.
14. HENDRICKSON, R., and J. W. KESTERSON. Orange concentrate evap-
orator scale identified as hesperidin. Citrus 14: No. 14, 26-7.
1952.
15. HIGBY, R. H. Methods for recovery of flavanone glycosides. U. S.
Patent No. 2,421,061. May 27, 1947.
16. HIGBY, R. H. Methods for recovery of naringin. U. S. Patent No.
2,421,062. May 27, 1947.
17. HOFFMAN, E. Ueber hesperidin. Deut. Chem. Gesell. Ber. 1: 685-90.
1876.
18. KEENAN, G. L. The occurrence of crystalline naringin on grapefruit
rind. Science. 104: 211. 1946.
19. LEBRETON, P. Sur la matiere cristalline des orangettes. Jour. de
Pharmacie 377. 1828.
20. MAURER, ROBERT H., E. M. BURDICK and C. W. WAIHEL. Distribution
of naringin in Texas grapefruit. Lower Rio Grande Valley Citrus
and Vegetable Institute Fourth Annual Proceedings. 1950. Wes-
laco, Texas.
21. POORE, H. D. Recovery of naringin and pectin from grapefruit resi-
due. Ind. Eng. Chem. 26: 637-9. 1934.
22. PULLEY, G. N. Solubility of naringin in water. Ind. Eng. Chem.
Anal. Ed. 8: 360. 1936.
23. PULLEY, G. N., and H. W. VON LOESECKE. Preparation of rhamnose
from naringin. J. Amer. Chem. Soc. 61: 175. 1939.
24. ROSENMUND, K. W., and MARGARETHE ROSENMUND. Synthesis of
naringenin and phloretin. Ber. 61B: 2608-12. 1928.
25. RUSZNYAK, I., and A. SZENT-GYORGYI. Vitamin P: Flavanols and
Vitamins. Nature 138: 27. 1936.
26. RYGG, G. L., and E. M. HARVEY. Behavior of pectic substances and
naringin in grapefruit in the field and in storage. Plant Physiol.
13: 571-86. 1938.
27. SHINODA, J., and S. SATO. New synthesis of polyhydroxychalcones,
polyhydrochalcones and polyhydroxyflavanones. II Synthesis of
naringin and sakuranetin. Jour. Pharm. Soc. Japan. 48: 117-119.
1928.







Naringin, A Bitter Principle of Grapefruit 29

28. SZENT-GYORGYI, A. Methoden zur herstalhing von citrin. Ztschr. of
Physiol. Chem. 255: 126-131. 1938.
29. TUTIN, F. Constitution of Eriodictyol of homoeriodictyol, and of
hesperitin. Proc. Chem. Soc. 26: 223. 1911.
30. WILL, W. Naringin. Ber. 18: 1311-25. 1885.
31. WooD, I. F., and H. M. REED. Maturity studies of Marsh seedless
grapefruit in the lower Rio Grande Valley. Tex. Agr. Exp. Sta.
Bul. 562: 5-39. 1938.
32. ZEMPLEN, GEYA, and REZSO BOGNAR. Synthesis of hesperidin. Berichte
de Deutschen chemischen Gesell. 76: 773-775. 1943.
33. ZOLLER, H. F. Components of American grapefruit. Ind. Eng. Chem.
10: 364-75. 1918.















APPENDIX
TABLE 8.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF DUNCAN GRAPEFRUIT.
Blk. VII Row E Tree 2


Component Parts of Fruit-- /


Juice


Albedo IFlavedo


Rag and
Pulp


Seeds ii Juice


IAlbedo F


i- i


28.0 19.9
29.0 24.2
38.2 22.6
40.6 22.5
38.9 26.5
40.5 22.0
42.6 21.6
43.2 22.1


- I



7.9
8.6
7.5
8.2
7.3
7.8
7.2
6.7


- I
35.8
31.3
26.6
23.9
23.0
25.5
23.9
25.1


-

8.4 8.6
6.9 9.1
5.1 I 10.0
4.8 10.7
4.3 10.6
4.2 II 10.5
4.7 11.8
2.9 10.7


18.1
16.3
19.2
20.2
19.1
19.9
22.2
20.2


Dry Solids--%
Rag and
lavedo Pulp

-




21.0 14.1
19.6 14.5
22.1 16.2
23.2 16.0
22.7 15.9
24.0 16.1
26.2 17.7
23.8 14.6


Date


4-28-52 .
5-1-51 .. I
6-1-51 ...-
7-1-51 ....
8-1-51 ....
9-1-51 ....
10-1-51 ....
11-1-51 ...
12-1-51 ...
1-1-52 ....
2-1-52 ..
3-1-52 ....
4-1-52 ....
I


Seeds






30.0
35.0
35.0
39.0
38.0
40.0
45.0
42.0


Whole
Fruit

33.0
29.9
21.2
17.3
15.6
15.2
15.2
15.9
16.5
16.1
16.3
17.8
15.6


I













TABLE 9.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF MARSH GRAPEFRUIT.


Blk. II


Row 19


Tree 7


Component Parts of Fruit--%
Rag and
Juice Albedo Flavedo Pulo i Seeds


S I I

I

29.5 21.1 8.1 40.5 0.8
40.9 22.2 8.8 27.5 0.6
46.0 22.0 8.1 23.4 0.5
44.4 20.2 8.1 27.0 0.3
44.3 21.9 8.2 25.3 0.3
50.6 21.2 8.3 19.6 0.3
44.2 21.6 7.9 25.9 0.4
46.7 21.4 7.6 24.0 0.3


Dry Solids--%
SRag and
Juice Albedo Flavedo Pulp

-


I
8.4 18.0 22.2 13.5
8.5 15.7 19.4 14.2
9.0 16.4 20.1 15.1
9.1 16.2 20.7 13.6
8.7 15.8 19.8 12.9
8.8 16.6 20.3 14.4
8.9 16.7 20.4 12.6
8.6 14.9 19.0 12.3


Whole
Seeds Fruit

27.8
26.4
24.4
18.0
15.5
30.0 13.7
30.0 12.7
32.0 13.0
45.0 12.8
38.0 12.2
44.0 12.6
40.0 12.6
55.0 11.8


Date II


4-11-52 .
5-1-51 ..
6-1-51 ....
7-1-51 .... 1
8-1-51 ....
9-1-51 ....
10-1-51 ..
11-1-51 ...
12-1-51 -
1-1-52 .... I
2-1-52 ....
3-1-52 ....
4-1-52 ....
















TABLE 10.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF FOSTER GRAPEFRUIT.


Blk. XX


Row G


Tree 10


II
H _Component Parts of Fruit-%
Date I I Rag and
Juice Albedo Flavedo IPulp


4-21-52 .. -
5-1-51 ... I -
6-1-51 .... -
7-1-51 .... I
8-1-51 .... -
9-1-51 .... 23.6 21.9 8.1
10-1-51 ... | 28.4 23.5 8.2
11-1-51 .... 40.1 22.8 8.0
12-1-51 .. 42.3 22.7 8.9
1-1-52 .... 40.7 24.7 7.0
2-1-42 .. 41.6 23.0 7.6
3-1-52 ... 47.0 22.3 7.4
4-1-52 .. I 43.4 20.0 6.5


Ij Dry Solids-%
II Rag and
I Seeds Juice Albedo Flavedo Pulp


SI -

I -
If .-~ I-
I ~-
40.0 6.4 8.2 18.9 22.8 13.2
34.9 5.0 8.5 16.9 20.6 13.4
24.3 4.8 8.7 17.2 21.1 14.3
22.0 4.1 8.7 17.6 29.3 14.1
23.4 4.2 9.0 17.3 21.1 14.1
24.7 3.1 8.8 17.3 20.6 13.4
21.3 2.0 9.3 17.6 21.3 14.7
27.4 2.7 9.6 19.2 21.7 13.4
I I 1


Whole
Seeds Fruit

30.6
27.5
21.2
17.2
|15.1
30.0 15.0
30.0 14.1
32.0 14.1
31.0 14.6
29.0 13.8
36.0 13.7
68.0 14.4
42.0 14.2












TABLE 11.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF THOMPSON GRAPEFRUIT.


Blk. I


Row I


Tree 37


Component Parts of Fruit-% i
Rag and I
Juice Albedo Flavedo Pulp Seeds


--. I I !


36.3 18.4 7.9 35.6 1.8 II
43.0 20.1 9.1 27.0 0.8 II
47.8 22.3 9.1 20.2 0.6
53.2 18.9 8.8 18.5 0.6 I
41.9 20.6 8.6 28.2 0.6 I
54.6 16.3 8.1 20.4 0.6 I
51.9 19.2 7.9 20.5 0.5 I
49.3 17.6 7.9 24.7 0.5
1I I I


Dry Solids-%
SRag and
Juice Albedo Flavedo IPulp

I _



9.0 18.4 22.6 15.5
9.0 16.7 19.4 15.2
9.2 16.7 20.1 15.7
9.4 17.6 20.3 14.8
9.1 168 20.2 13.3
9.4 18.0 22.2 14.3
9.1 17.3 21.1 14.2
8.7 17.4 20.4 13.6
1 I


SWhole
Seeds Fruit

31.2
26.5
21.6
17.8
S 14.8
30.0 14.4
30.0 13.3
35.0 13.3
41.0 13.0
33.0 13.0
38.0 13.0
40.0 12.8
45.0 12.6


Date I


4-18-52 ..
5-1-51
6-1-51 ....
7-1-51 ....
8-1-51 .. I'
9-1-51 ....
10-1-51 ....
11-1-51 ... I
12-1-51 .... I
1-1-52 .
2-1-52 _-
3-1-52 ....
4-1-52 ...
I















TABLE 12.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF RUBY RED GRAPEFRUIT.


Blk. XX
IC
[I Comoonent Parts of Fruit-%
Date II Rag and
I Juice Albedo Flavedo Pulp

4-28-52 .. --
5-1-51 .... -
6-1-51 .... -
7-1-51 ... -
8-1-51 ...- -
9-1-51 .... 36.5 19.8 8.3 34.8
10-1-51 -.. 37.5 25.7 1 9.5 26.7
11-1-51 ... 49.6 18.9 9.5 21.5
12-1-51 .... 49.2 19.4 8.7 22.2
1-1-52 -.. 48.7 20.6 8.7 21.6
2-1-52 .... 50.8 18.2 8.3 22.4
3-1-52 -... 48.4 18.8 7.6 24.8
4-1-52 .... 49.1 19.1 8.1 23.4


Row N


Seeds II
I I

I I

0.6 i
0.6
0.5 I
0.5 I
0.4
0.3 I
0.4 II
0.3 II
I I


Tree 9


Dry Solids--%
SRag and Whole
Juice Albedo Flavedo Pulp Seeds Fruit

S- 31.5
-- 26.5
22.0
-- 17.0
.-.- 14.4
7.7 18.4 22.8 13.9 30.0 13.3
7.9 14.2 19.6 13.9 30.0 12.4
8.1 16.1 20.6 14.8 33.0 12.4
8.2 17.0 20.6 13.5 41.0 12.3
8.1 16.7 20.2 12.7 33.0 12.0
7.7 16.8 19.6 11.9 40.0 11.4
7.8 17.3 20.2 12.1 38.0 11.7
7.6 16.7 19.4 12.0 40.0 11.4
I (Il













TABLE 13.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF SHADDOCK (THONG DEE).


Blk. III


Row B


Tree 14


Component Parts of Fruit--%/


Albedo I Flavedo


Rag and
Pulp






42.0
36.0


Seeds


Dry Solids-%
Rag and


Juice Albedo Flavedo

-


20.2
18.2
18.1
17.8
18.5
18.8
18.3
20.7


Pulp I


1 Whole
Seeds Fruit


I -


22.8 16.4
21.3 15.3
21.4 15.0
20.6 16.4
22.2 15.2
22.0 15.3
21.6 14.3
24.8 15.7


30.0
35.0
42.0
45.0
44.0
49.0
47.0
51.0


Date I


Juice


4-11-52
5-1-51 ....
6-1-51 ....
7-1-51 ...
8-1-51 ....
9-1-51 ....
10-1-51 ....
11-1-51 ....
12-1-51 .... i
1-1-52 ..
2-1-52 .... [
3-1-52 .... I
4-1-52 ....
I I


----~-




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs