• TABLE OF CONTENTS
HIDE
 Title Page
 Table of Contents
 Introduction
 Review of literature
 Physical and chemical characte...
 Experimental procedure
 Experimental results and discu...
 Possible utilization of naring...
 Summary
 Literature cited
 Appendix














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 511A
Title: Naringin, a bitter principle of grapefruit
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027260/00001
 Material Information
Title: Naringin, a bitter principle of grapefruit occurrence, properties and possible utilization
Series Title: Bulletin Agricultural Experiment Stations, University of Florida
Physical Description: 27 leaves : ill. ; 29 cm.
Language: English
Creator: Kesterson, J. W
Hendrickson, Rudolph
Publisher: University of Florida, Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1957
 Subjects
Subject: Glycosides   ( lcsh )
Citrus fruits   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: leaves 25-27.
Statement of Responsibility: J.W. Kesterson and R. Hendrickson.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00027260
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000881621
oclc - 12034432
notis - AEH9490

Table of Contents
    Title Page
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 3
        Page 4
        Page 5
    Physical and chemical characteristics
        Page 6
        Page 7
    Experimental procedure
        Page 8
        Page 9
        Page 10
        Page 11
    Experimental results and discussion
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
    Possible utilization of naringin
        Page 23
    Summary
        Page 24
    Literature cited
        Page 25
        Page 26
        Page 27
    Appendix
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
Full Text




(Originally printed January 1953)


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
J. R. BECKENBACH, Director
GAINESVILLE, FLORIDA
(A contribution from the Citrus Experiment Station)

Revision of no.

Naringin, A Bitter Prin-r

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


Bulletin 511A


December 1957

















CONTENTS

Page


INTRODUCTION .......... -------.......----- ..---------- 3

REVIEW OF LITERATURE ....................................... ..-------- 3

PHYSICAL AND CHEMICAL CHARACTERISTICS ....----.........------------------ 6

EXPERIMENTAL PROCEDURE .................... ...------------- ----------------- 8


Collection of Sam ples --........................... ................. 8

Methods of Analysis .................---------....------------- 11

EXPERIMENTAL RESULTS AND DISCUSSION ............................---................... 12

Naringin Content of Whole Grapefruit and Shaddock ........................ 12

N aringin Content of Juice ................................. .. .. .. ............... 21


Distribution of Naringin ................................- -......... 21

Component Parts of Grapefruit and Shaddock Fruits ....................... 23

POSSIBLE UTILIZATION OF NARINGIN .................. .......................... 23

SUM MARY ...................-..........-.......... ........... ..................- 24

LITERATURE CITED ......................................-------------- .. 25

A PPEN DIX ...................... ................. ... .......... ................. ................. ... 28









Naringin, A Bitter Principle of Grapefruit

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

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 nar-
ingin 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 a profusion of literature on the subject, only mea-
ger data exist concerning the distribution of naringin in various
components of fruit of different varieties of grapefruit. In this
work the authors have reported results of broad scale sampling
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-
'Chemist and Assistant Chemist, Citrus Experiment Station, Lake Al-
fred, Florida.
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. HENDRICKSON

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 nar-
ingin 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 a profusion of literature on the subject, only mea-
ger data exist concerning the distribution of naringin in various
components of fruit of different varieties of grapefruit. In this
work the authors have reported results of broad scale sampling
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-
'Chemist and Assistant Chemist, Citrus Experiment Station, Lake Al-
fred, Florida.
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 hesperi-
din 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 prod-
uct 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 occurred in nature
as a flavanone glucoside 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-
generation 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 AICl3.
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 increased
at all temperatures, most at 320 F. and least at 520 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
consisting principally of peel, membrane and seeds, contained
about 0.75% naringin, the amount depending mainly upon the







Naringin, A Bitter Principle of Grapefruit


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 68 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 in-
vestigate 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 carbohydrates syn-
thesized in the chlorophyllous tissue. He advanced the hypothe-
sis that, in combination with the phenolic glucosides, glucose
forms a soluble, easily hydrolizable compound that is thus tem-
porarily 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 in Texas grapefruit the most
significant change in naringin content during the harvesting
season occurred between October 13 and November 17 in 1948.
During this period the naringin decreased on the average: 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% nar-
ingin 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,
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.







Florida Agricultural Experiment Stations


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 110" C. it has a melting point of
1710 C. and has the composition of C27H32014.2H20 (2). Re-
crystallized from water, it has six additional waters of crystalli-
zation and melting point of 830 C. Its structural formula (2, 32)
has been confirmed as being:



S1-C0H H 0 O
HCOH 0 HOCH

HHH
CH ..C Hd 0 0

3CH 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 spe-
cific rotation of [ 1 ] -= -82 in alcohol. Naringin is insoluble
in ether, chloroform, benzene or ligroin; yet is soluble to a vary-
ing degree in water, alcohol, acetone, glacial acetic acid or pyri-
dine. Calcium hydroxide, as well as other alkalis, greatly in-
creases 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 7

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

Temperature Solvent Solubility
SC. Percent by Volume
6 .02
35 .08
45 Water (22) .20
55 .72
65 4.2
75 10.8

5 3.3
21 Ethyl Alcohol 95% 4.2
39 6.5

21 3.0
S 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 pictori-
ally the physical location of naringin in grapefruit, as illustrated
in Fig. 2. The yellow coloration that develops when sodium hy-
droxide is added to a naringin solution is the basis of a more
specific and reliable colorimetric method (8). The color of flava-
none glycosides in hydrochloric acid solution and alkali after re-
duction is helpful in distinguishing naringin from other flava-
nones (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 hydrolized to one mole each of nar-
ingenin, 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. 53.5 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 Dun-
can, Marsh, Thompson, Foster and Ruby Red, were included.
Their genetic relationship is given in Fig. 4. It has been com-
monly accepted, but not established, that the grapefruit is 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.




I I


Naringin, A Bitter Principle of Grapefruit


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
Top inside
Top outside
Bottom inside
Bottom outside


West
Top inside
Top outside
Bottom inside
Bottom outside


North
Top inside
Top outside
Bottom inside
Bottom outside


South
Top inside
Top outside
Bottom inside
Bottom outside


As the fruit increased in size, it was found necessary to re-
duce the number per sample. In these samples one fruit was
taken from each of the cardinal points from both the top and the


THCMPSON PINK VARIETY
Sport of Marsh Seedless


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







Naringin, A Bitter Principle of Grapefruit


bottom of the tree to give a total of eight. Fruits of 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 par-
ticular 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 de-
velopment 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 sea-
son. 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 weights, 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 VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF DUNCAN GRAPEFRUIT.*
Blk. VII Row E Tree 2


Date
Date Diameter
in.

4-28-52 .. 0.50
5-1-51 .... 1.2
6-1-51 .... 2.3
7-1-51 .... || 3.3
8-1-51 .... 3.7
9-1-51 .... [ 3.8
10-1-51 .... 4.2
11-1-51 .... 4.5
12-1-51 .... 4.6
1-1-52 .... 4.7
2-1-52 .... 4.8
3-1-52 .... 4.6
4-1-52 .... 4.8
I I


Whole Fruit


Wet Wt.
Gins.

1.52
14
76
184
306
377
500
577
619
670
742
666
721


Dry Wt.
Gms.

0.33
4.3
16
32
48
57
76
92
102
108
125
119
112


Glucoside
Content
Gms.

0.25
1.4
2.4
2.6
2.8
2.1
2.6
2.5
2.6
3.0
3.1
2.6
2.5


o Brix






8.4
8.9
9.8
10.5
10.4
10.3
11.6
10.5


Juice

Acid
%





1.9
1.6
1.7
1.8
1.5
1.6
1.7
1.4


Glucoside
Content
% by Vol.





0.031
0.024
0.028
0.032
0.036
0.030
0.022
0.016


Distribution of Glucoside--%


Juice






1.5
1.3
2.4
3.0
3.1
2.8
2.2
1.9


Albedo






49.0
53.2
59.0
59.8
61.7
56.2
55.6
58.3


Flavedo IRag
I and Pulp


* Average value for either 8 or 16 fruit.











TABLE 3.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF MARSH GRAPEFRUIT.*
Blk. II Row 19 Tree 7


Date |
| Diameter
in.

4-11-52 .. 0.53
5-1-51 .... 0.95
6-1-51 .... 2.0
7-1-51 .... 2.6
8-1-51 .... 2.9
9-1-51 .... 3.6
10-1-51 .... 3.7
11-1-51 .... 3.9
12-1-51 ..- 4.1
1-1-52 .... 4.3
2-1-52 .... 4.5
3-1-52 .... 4.3
4-1-52 .... 4.4


Whole Fruit
| |
Wet Wt. Dry'
Gms. Gm

1.4 0.
9.0 2.
44 11
111 20
178 28
295 40
339 43
419 55
466 60
550 67
584 74
552 69
578 68


Wt.
s.

3
3


Glucoside
Content
Gms.

0.2
0.8
1.6
1.6
1.7
2.2
1.7
1.8
1.8
2.1
2.2
1.7
1.7


Juice


Brix Acid
S%

-



8.2 1.9
8.3 1.6
8.8 1.5
8.9 1.6
8.5 1.4
8.7 1.3
8.7 1.4
8.4 1.3


Glucoside
Content
% by Vol.

I--



0.029
0.031
0.035
0.029
0.028
0.030
0.024
0.019


Distribution of Glucoside--%
I I
Juice Albedo Flavedo Rag
and Pulp


* Average value for either 8 or 16 fruit.













TABLE 4.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF FOSTER GRAPEFRUIT.*
Blk. XX Row G Tree 10


Whole

I Diameter Wet Wt.
S in. Gms.

0.54 1.5
| 1.1 12
S 2.5 82
I 3.3 211
| 3.8 347
4.0 442
4.5 562
4.6 641
4.8 709
4.9 769
5.0 800
[ 4.9 781
5.1 859


Fruit

Dry Wt.
Gms.

0.5
3.2
17
36
52
67
79
91
102
106
109
112
122


SGlucoside
Content
Gms.

0.2
1.4
2.7
3.1
3.1
3.2
3.1
3.1
3.6
3.5
3.6
3.4
3.4


Brix






8.0
8.3
8.6
8.5
8.9
8.7
9.2
9.5


Juice

Acid
%





1.7
1.4
1.3
1.3
1.2
1.2
1.2
1.2


Glucoside
Content
% by Vol.





0.031
0.016
0.026
0.029
0.035
0.033
0.037
0.015


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


* Average value for either 8 or 16 fruit.


Date



4-21-52 ..
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 ....












TABLE 5.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF THOMPSON GRAPEFRUIT.*
Blk. I Row I Tree 37


Whole Fruit

Diameter Wet Wt. Dry Wt.
in. Gms. Gms.

0.53 1.4 0.5
1.05 10 2.5
S 2.1 51 11
2.7 122 22
3.0 181 27
3.3 254 36
S 3.5 320 43
3.8 375 50
3.9 409 53
S 3.9 421 55
4.1 459 60
4.2 497 64
S 4.2 495 62


Glucoside
Content Brix
Gms.

0.2 -
0.9


Juice

Acid
%





1.7
1.4
1.3
1.3
1.2
1.2
1.2
1.2


Glucoside
Content
% by Vol.





0.028
0.035
0.037
0.029
0.023
0.019
0.020
0.017


Distribution of Glucoside--%

Juice Albedo Flavedo Rag
and Pulp

] -



1.6 49.0 9.1 40.3
2.9 55.7 9.8 31.6
3.5 56.0 8.0 32.5
3.0 59.6 8.7 28.7
2.2 59.5 6.0 32.3
2.7 55.5 7.0 34.8
2.6 59.1 6.0 32.3
2.1 54.3 5.6 38.0


* Average value for either 8 or 16 fruit.


Date



4-18-52 ..
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 ....














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


I Whole Fruit II Juice II


Glucoside
Content
% by Vol.





0.019
0.027
0.030
0.027
0.021
0.018
0.016
0.016


Juic






0.9
1.6
2.6
2.5
2.0
2.1
1.6
1.8


Distribution of Glucoside-%

e Albedo Flavedo I
| and





50.3 9.2 3
57.8 9.9 3
53.0 12.4 3
60.9 7.6 2
62.7 6.7 2
61.6 6.0 3
62.9 4.6 3
65.6 5.5 2


Rag
Pulp






9.6
0.7
2.0
9.0
8.6
0.3
0.9
7.1


* Average value for either 8 or 16 fruit.













TABLE 7.-MONTHLY VARIATION IN WHOLE FRUIT, JUICE AND GLUCOSIDE CONTENT OF SHADDOCK (THONG DEE).*
Blk. III Row B Tree 14


* Average value for either 4 or 8 fruit.







Naringin, A Bitter Principle of Grapefruit


100
80 DUNCAN GRAPEFRUIT
60-

40-



20 0 Whole Fruit
Dry Weight

10
8-
6

4-
z


(.9
z

z

1.0
0.8-
0.6-

0.4


0.2


0 .1 1 t I I I I
A M J J A S O 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-


1951-52 SEASON
Fig. 6.-Naringin content on a per-fruit basis for five varieties of grapefruit
and Thong Dee shaddock.







Naringin, A Bitter Principle of Grapefruit


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
lack of adequate analytical methods, 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 with-
in the limits of 0.02 to 0.03 percent throughout the entire sea-
son.
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 grad-
ually 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).







'22 Florida Agricultural Experiment Stations

The hand juice extractor used in this study folded and
squeezed a half grapefruit and required only a moderate amount
of pressure to extract the juice. The juice extracted under these

100
80 DUNCAN GRAPEFRUIT


60




I-
4LL

0
(,
20- o Albedo
w ob Rag a Pulp
z
o Flavedo
M aD Juice
0

Z10







.. 4 -

0
0



I---




S 0 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


conditions was found to contain an average of 1 to 3 percent of
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 va-
rieties, Duncan grapefruit was used to show the overall changes
in the distribution of naringin (Fig. 7). This graphically illus-
trated that time of season was not a variable which influenced
the distribution of the glucoside. The one exception was a con-
sistent, but small, decrease in the naringin content of the flavedo,
in all the samples except shaddock. The distribution 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 sev-
eral 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-







Florida Agricultural Experiment Stations


class confections, especially those flavored with citrus fruit fla-
vors. Being harmless, the bitter principle from grapefruit
makes a suitable bitters for these purposes. It is sold commer-
cially under the name "Amerin".
Naringenin, the product obtained by the acid hydrolysis of
naringin, may be further hydrolyzed by potassium hydroxide to
yield p-couramic 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 acti-
vated 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 vita-
min 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 therapeu-
tic 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








Naringin, A Bitter Principle of Grapefruit


larger, the naringin content on a percentage basis became lower.
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 precent 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 Lee shad-
dock.
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 derivaties. Ber. 62B : 3016-21.
1929.
4. ASAHINA, Y., and M. INUBUSE. Flavanone glucosides II. Constitution
of naringin. 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 grape-
fruit. Calif. Citrograph 17 : 94. 1932.








26 Florida Agricultural Experiment Stations

7. BRAVERMAN, J. B. S. Citrus products. Chemical compositions and
chemical technology. 424 pp. 1949. Interscience Publishers, Inc.
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 graperuit 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 evaporator
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 Citru4
and Vegetable Institute Fourth Annual Proceedings. 1950. Wes-
laco, Texas.
21. POORE, H. D. Recovery of naringin and pectin from grapefruit residue.
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 nar-
ingin and phloretin. Ber. 61B : 2608-12. 1928.
25. RUSZNYAK, I., and A. SZENT-GYORGYI. Vitamin P: Flavanols and
Vitamins. Nature 138 : 27. 1936.








Naringin, A Bitter Principle of Grapefruit


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.
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 hes-
peritin. 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-%
Rag and I
Albedo Flavedo Pulp






19.9 7.9 35.8
24.2 8.6 31.3
22.6 7.5 26.6
22.5 8.2 23.9
26.5 7.3 23.0
22.0 7.8 25.5
21.6 7.2 23.9
22.1 6.7 25.1


Seeds






8.4
6.9
5.1
4.8
4.3
4.2
4.7
2.9


Juice Albedo

I
I-
I-
--
-- --
8.6 18.1
9.1 16.3
10.0 19.2
10.7 20.2
10.6 19.1
10.5 19.9
11.8 22.2
10.7 20.2


Dry Solids-%
I Rag and
Flavedo Pulp


-



14.1
14.5
16.2
16.0
15.9
16.1
17.7
14.6


SWhole
Seeds I Fruit


30.0
35.0
35.0
39.0
38.0
40.0
45.0
42.0


Date


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


Juice






28.0
29.0
38.2
40.6
38.9
40.5
42.6
43.2




TABLE 9.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF MARSH GRAPEFRUIT.
Blk. II Row 19 Tree 7


Component Parts of Fruit--%
Albedo Flaved Rag and
I Albedo Flavedo I Pulp


Date


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 ....


Juice


Seeds





0.8
0.6
0.5
0.3
0.3
0.3
0.4
0.3


Dry Solids-%
Rag and ]
Flavedo Pulp I


TABLE 10.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF FOSTER GRAPEFRUIT.
Blk. XX Row G Tree 10


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

4-21-52 .. -
5-1-51 .... -
6-1-51 .... -
7-1-51 .... -
8-1-51 .... -
9-1-51 ... 23.6 21.9 8.1 40.0
10-1-51 .... 28.4 23.5 8.2 34.9
11-1-51 .... 40.1 22.8 8.0 24.3
12-1-51 .... 42.3 22.7 8.9 22.0
1-1-52 .... 40.7 24.7 7.0 23.4
2-1-52 .... 41.6 23.0 7.6 24.7
3-1-52 .... 47.0 22.3 7.4 21.3
4-1-52 .... 43.4 20.0 6.5 27.4


Seeds

I I



6.4
Kn


Juice





8.2
8.5
8.7
8.7
9.0
8.8
9.3
9.6


Albedo


I-


18.9
16.9
17.2
17.6
17.3
17.3
17.6
19.2


Dry Solids-%
Rag and
Flavedo Pulp





22.8 13.2
20.6 13.4
21.1 14.3
29.3 14.1
21.1 14.1
20.6 13.4
21.3 14.7
21.7 13.4


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


Juice





29.5
40.9
46.0
44.4
44.3
50.6
44.2
46.7


Albedo





18.0
15.7
16.4
16.2
15.8
16.6
16.7
14.9


Seeds





30.0
30.0
32.0
45.0
38.0
44.0
40.0
55.0


Whole
Fruit

27.8
26.4
24.4
18.0
15.5
13.7
12.7
13.0
12.8
12.2
12.6
12.6
11.8













TABLE 11.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF THOMPSON GRAPEFRUIT.
Blk. I Row I Tree 37


Parts of Fruit-%
I Rag and
Flavedo I Pulp


II
11

Seeds




I

1.8
0.8
0.6 1
0.6
0.6
0.6
0.5
0.5 I


Juice


Albedo





18.4
16.7
16.7
17.6
16.8
18.0
17.3
17.4


Dry Solids-%


Flavedo





22.6
19.4
20.1
20.3
20.2
22.2
21.1
20.4


Rag and
Pulp





15.5
15.2
15.7
14.8
13.3
14.3
14.2
13.6


Date


4-18-52 ..
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 -...


Juice





36.3
43.0
47.8
53.2
41.9
54.6
51.9
49.3


Component

Albedo |





18.4
20.1
22.3
18.9
20.6
16.3
19.2
17.6


Seeds





30.0
30.0
35.0
41.0
33.0
38.0
40.0
45.0


Whole
Fruit

31.2
26.5
21.6
17.8
14.8
14.4
13.3
13.3
13.0
13.0
13.0
12.8
12.6












TABLE 12.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF RUBY RED GRAPEFRUIT.
Blk. XX Row N Tree 9

Component Parts of Fruit-% Dry Solids-%
Date I I Rag and ) Rag and ] Whole
Juice Albedo Flavedo Pulp Seeds Juice Albedo Flavedo Pulp Seeds \ Fruit

4-28-52 .. 31.5
5-1-51 .... 26.5
6-1-51 .... 22.0
7-1-51 .... 17.0
8-1-51 .. 14.4
9-1-51 .... 36.5 19.8 8.3 34.8 0.6 7.7 18.4 22.8 13.9 30.0 13.3
10-1-51 ... 37.5 25.7 9.5 26.7 0.6 7.9 14.2 19.6 13.9 30.0 12.4
11-1-51 ... 49.6 18.9 9.5 21.5 0.5 8.1 16.1 20.6 14.8 33.0 12.4
12-1-51 .... 49.2 19.4 8.7 22.2 0.5 8.2 17.0 20.6 13.5 41.0 12.3
1-1-52 .... 48.7 20.6 8.7 21.6 0.4 8.1 16.7 20.2 12.7 33.0 12.0
2-1-52 .... 50.8 18.2 8.3 22.4 0.3 7.7 16.8 19.6 11.9 40.0 11.4
3-1-52 .... 48.4 18.8 7.6 24.8 0.4 7.8 17.3 20.2 12.1 38.0 11.7
4-1-52 .... 49.1 19.1 8.1 23.4 0.3 7.6 16.7 19.4 12.0 40.0 11.4
III













TABLE 13.-DISTRIBUTION AND DRY SOLIDS CONTENT OF THE COMPONENT PARTS OF SHADDOCK (THONG DEE).
Blk. III Row B Tree 14


Comp nent

Juice Albedo
--




14.1 32.4
18.1 36.8
23.4 31.3
26.9 29.3
30.2 31.1
34.0 28.4
29.8 28.1
27.9 28.6


Parts of Fruit--%


Flavedo





5.5
4.9
8.1
11.6
8.5
8.5
8.9
8.3


Rag and
Pulp

-- i



42.0
36.0
33.0
28.0
26.9
25.8
30.3
32.3


Seeds

-


Juice

-- I
-- I
-- t
-- I

10.6
10.2
10.7
10.3
11.0
10.6
10.6
11.5


Albedo





20.2
18.2
18.1
17.8
18.5
18.8
18.3
20.7


Dry Solids--%
I Rag and
Flavedo Pulp


Date


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 ....


Seeds





30.0
35.0
42.0
45.0
44.0
49.0
47.0
51.0


Whole
Fruit

25.2
22.1
22.0
20.4
18.3
17.9
16.6
16.6
16.9
16.4
16.3
15.9
17.7


NMOI1




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