Application of the principles of jelly making to Hawaiian fruits

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Title:
Application of the principles of jelly making to Hawaiian fruits
Series Title:
Bulletin / Hawaii Agricultural Experiment Station ;
Physical Description:
24 p., 1 leaf of plates : ill. ; 23 cm.
Language:
English
Creator:
Ripperton, J. C ( John Carson ), 1891-1960
Publisher:
G.P.O.
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Jelly   ( lcsh )
Tropical fruit -- Utilization -- Hawaii   ( lcsh )
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federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references.
Statement of Responsibility:
by J.C. Ripperton.

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Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029612901
oclc - 10055896
Classification:
lcc - S399 .E2 no.47
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AA00014540:00001


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HAWAII AGRICULTURAL EXPERIMENT STATION
HONOLULU, HAWAII

BULLETIN No. 47


Under the supervision of the
UNITED STATES DEPARTMENT OF AGRICULTURE


APPLICATION OF THE

PRINCIPLES OF JELLY MAKING

TO HAWAIIAN FRUITS




BY

J. C. RIPPERTON, Chemist






Issued June 21, 1923


WASHINGTON
GOVERNMENT PRINTING OFFICE
1923


E...'




Sl.."
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S* .. .. ..




.. :. .. i .:^ *
AWAII AGRICULTURAL EXP IMENT ': STATION








A. C. TRUE, Director.





WALTE H. EVANS, Chief, Division of Insular tatio i, Offe E
.HAWAII AGRICULTURAL EXPERIMENT ST O
... 4 ... .-" .. i 7 7
[Under the supervision of the States Relations Srvice United St Extension Ags e
A C. TRUE, Director.lla r in H e E..
E.W.ALLEN, Chief, Office of Experi.ment Stations.
WATEn H. EVANS, Chief, Division of Insular 8&&Aion2 0^% tiI
Experiment Stations.
STAFF. ... i ,:
.. .. ... ..
J. M. WESTGATE, Agronomist 1w Ckhrgei. .
H. L. CHUNG, Specialist in Tropical Agronomy. NX.
W. T. POPE, Horticulturist.''
J. C. KIPPERTON, Chemist.
R. A. GOFF, In Charge of Glenwood Substation and Extension. AigifSl~y
for Island of Hawaii.
NnLLIE A. RUSSELL, Collaborator in Home EBmonoies.







; .:A





... *.- ...
-...-. . ...... ...-:..".-.::.-
V NO : ::i:










APPLICATION OF THE PRINCIPLES OF JELLY
MAKING TO HAWAIIAN FRUITS.


CONTENTS.
Page. Page.
Introduction .............................. 1 Other Hawaiian fruits for jelly making...... 14
Methods..................................... 1 Consistency of jellies as affected by the physi-
the guava for jelly making.................. 4 cal properties of pectin..................... 22
S Efet of varying proportions of sugar, pec- Summary............ .................. 23
tin, and acid in jelly making ............ 9

INTRODUCTION.
Although tropical fruit products have been given wide publicity
within recent years and there is an ever-increasing demand for them
on the world markets, jelly making from tropical fruits remains as
yet a -comparatively undeveloped industry. Probably the only
two tropical fruit jellies of any commercial importance at the present
time are those made from guava (Psidium guayava) and poha (Physalis
per iana). Guava jelly, owing to the comparatively small cost of
production and the growing of the wild fruit in abundance, is the
standard jelly as well as the basic product of the fruit jelly industry
in Hawaii. Poha jelly production is as yet small, owing to the
limited supply and high cost of the frdit. Since the exportation
in the fresh state df many Hawaiian fruits is prohibited by quarantine
regulations, the fruit jelly-making industry in Hawaii should serve
as a stimulus for producing and exporting Hawaiian fruit products
ingreater abundance thaa is now the case.
Extensive studies have been made of, and formulae developed for,
the nakimg of jellies from every important fruit of the Temperate
Zone, but little or no study has been devoted to the making of jelly
from fruits from the Tropics. The writer, therefore, made an ex-
haustive study of the Hawaiian guava for jelly making for the
purpose of developing a systematic procedure by means of which
je 5 may successfully be made from any kind of jelly fruit." This
ulletin gives the results of the investigation.
METHODS.
A review of the different studies on jelly making showed that
there are no generally accepted methods for conducting a systematic
study of the jelly-making qualities of a fruit, and that the tendency
is to develop formula for different fruits rather than general prin-
ciples which will apply to all jelly fruits. The methods followed
by the writer require little time and simple apparatus, and while
the results obtained from their use can not be considered in the
1 t of accurate quantitative results, they are, it is thought, suffi-
dietly acycurte for a practical study of jelly making.
S -L A fruit eontaeling the esential constituents for jellying, i. e., pectin and acid.






BULLETIN 47, HAWAII EXPERIMENT STATIOl.


DETERMINATION OF PECTIN IN FRUIT JUICES.
Careful search through literature failed to give any quick,'
tical method for determining the pectin content of fruit
a rule the pectin content is not determined, knd th i..qua
is indicated by specific gravity or by means of thie: rhy m
The Brix reading indicates at once the proportion of sugar
should be added to the juice in accordance with tables that
been worked out for apple juice, but since such tables are of .
value in connection with other fruits a separate table dust be co*
structed for each specific fruit.
Home economics text and cook books commonly advocates..
method of adding fruit juice to alcohol in a tumbler to doet&Dih
the pectin content of a juice. The appearance of the precilSitaC
pectin when poured out is taken as an indication of the content,4
the juice being said to contain a high percentage of pectin when.:i
the precipitate pours out in a single lump, only a medium quantity
when there are several small lumps, and not enough pe;FetMlAfo'
jelly making when there are no lumps. Many .substances, st.fi js
magnesium sulphate, can be used in place of alcohol tW precipi;~ta
the pectin. This method, while valuable for the housewife, was W" i
deemed sufficiently accurate to be of use in connection~ t i ib
present investigation. ; J 41i
Quantitative methods entailing precipitation, filtration, weign
and ignition require too much time for completion to:be o pcaoti
use .ij jelly making. {,. *:,f .f,,
By means of a cylinder, graduated to 25 cubic centimeteraslrii
fitted with a plunger,2 a pipette, to deliver: the jice to thfe Al ib4
drop by drop, and a piece of silk bolting cloth about 4 inches quW
the writer developed a method for determining the pectian 4otrgi:
of fruit juices. (PL I, Fig. 1.) .After 20 cubic centimeters ofi 95 pi
cent ethyl alcohol were measured into the cylinder, 10 cubic~oet iJ
meters of the juice to be tested- were added drop by drop; tn0i4
alcohol. The contents of the,cylinder was then filtered throi gh ti .
silk bolting cloth, which was ;ioHed back and forth in the hal
until the pectin precipitate gathered into a compact mass andlth.
alcohol ceased to run out.3 As soon as the pectin mass had heit
rolled into cylindrical shape it was slipped into the cylinder i*
shaken to the bottom. The plunger was then placed on top :of-i
mass and the volume in cubic centimeters, or "pectin number," i
noted. The operation required only three to five minutes with most,
of the juices tested, and duplicate results were had within a quarter
of a cubic centimeter. ,
The amount of alcohol which the pectin mass will retIain epA
of course on the pressure exerted. The purpose of rolling o
silk cloth is to remove the excess alcohol with no pressure a!
other than that exerted by its own weight. The purpose- 4 .7
plunger is not to exert pressure, but to make possible an acq,
reading of the pectin number. r
-The relationship. existing between the 'ipectin numb '. ,A
percentage of pectin was determined by ascerta4 iwpi ;
precipitate, that is, the impure pectin, for which purpose the m
2 A Nessler tube having the proper diameter can be used as the plunger.
SIn this operation timecan be saved by placing the cloth upon a folded towel to absorb the alcOM4B it,
the results obtained are not nearly so accurate as when no towel is used.
*-*!!, '






T JELLY MAKING WITH HAWAIIAN FRUITS. 3

followed by the Association of Official Agricultural Chemists was

STable I gives the "pectin number" and percentage, as well as the
~3 rix hydrometer reading of several guava juices and of one juice
each of the poha, grape, and roselle.

TABLE 1.-Comparison of "pectin number" and pectin per cent in fruit juices.

Pectin.
Fruit juice, b Brix
Fruit jice. reig. Character of precipitate.
a b

Number. Per cett. Degrees.
Guava ................ 3 0446 0.137 3.6 Spongy with medium long fibers.
Do-............... .578 .136 5.2 Do.
Do............... 5. .794 .151 7.0 Do.
Do................ 6, .963 .14 7.8 Do.
Do............... 7T 1.141 1 .157 11.8 Do.
Do................ 91 1.661 .10 9.6 Do.
Poha.................. 2J 431 .172 15. 4 Dense with long, tough fibers.
Grape................. 4 .222 12.6 Gela inoh; with very short fibers.
Roselle................. 5 .977 .16 3. Spongy with short fibers.

1 Average.
b
Table 1 shows that the factor is fairly constant for guava juice.
a
Any increase in this factor for juices having a higher pectin content
is, of course, due to the increased pressure exerted by the greater
bulk of precipitate and the resultant smaller proportion of alcohol
remaining in the mass. Guava juices, however, seldom contain a
pectin number greater than 7- or less than 3, and the factors within
this limit vary only little.
The factors for the juices of different fruits vary considerably.
This variation is directly traceable to the character of the precipitate
because the swelling power of the precipitate, or its capacity to absorb
alcohol, varies with the character of the pectin.
The Brix reading of a juice, as an indication of the pectin content,
is unreliable, unless only one fruit is used in the experiment. The
percentage of pectin in a juice may be computed by multiplying its
b
pectin number by the factor -* This method of computation was -
used throughout the investigation.5

PROPORTION OF SUGAR TO JUICE.

The following method was used for systematically determining the
best proportion of sugar to add to the fruit juice.
A series of jellies was made with varying quantities of sugar to 1
cupful8 of juice, a start being made with three-quarters of a cupful
of sugar to 1 cupful of juice. The quantity of sugar was increased a
quarter of a cup at a time until a sirup or gummy mass instead of a

4 Methods of Analysis of the Association of Official Agricultural Chemists. Revised to Nov. 1, 1919
Washington, D. C., 1920, p. 156.
For use of the "pectin number" method in investigational work, each worker should determine the
factor b for himself so as to eliminate eventually the personal factor. For practical work, however,
variations due to this cause are negligible.
Wherever the term "cupful" is used in connection with measurements of juice and sugar, 245 cubic
eeatimetes of juice and 200 grams of granulated sugar are taken as the equivalent. The actual volume.of
a half-pint cup is 236.6 cubic centimeters. However, the value assumed is believed to be nearer the actual
m measurements, made by the average jelly maker, than the true value.
!;






4 BUIZETEN 41, HAW&I .........AZl. .....

jelly resulted. The resultant "jelly series" was tlheni
determine the relative merits of ea of the different ro
sugar to juice. Each member of the series was brown
standard a consistency as possible.
CHEMICAL ANALYSIS OF JUICES AND JELLIES.
The methods of analysis recommended by the Association of .
Agricultural Chemists7 were employed in making analyses of
juices and jellies. Sucrose was determined by polarization bedlo .
and after inversion with hydrochloric acid, reducing sug,
volumetric Fehling-solution method of Munson and Walker and
pectin, by the alcohol precipitate method. The acidity was
determined by titrating with fifth-normal sodium hydroxid
phenolphthalem as indicator. Phenolphthalein sufficed fr w :
of a practical nature, even with the highly colored juices stuW
since the natural color of the juice faded somewhat, usually ch :|
to pale green, before the end point with the indicator was reae ..
and the color change of the latter was therefore readily discerniblAi
THE GUAVA FOR JELLY MAKING. .,. F :g
The common guava, which is used for jelly making, is a'conspic
part of the native vegetation of Hawaii. It grows over wiideT i I
of altitude and rainfall and on both the windward and the le sides of all the islands. The ripe fruit can be obtained the -ex :
round, but the main crop is produced from June to October., fd ,
Although many of the large guava-producing-areas are leasd ,by i
commercial jelly companies, large numbers of guava shrubs are WWJ iif
found growing along highways and on public lands where the B froi
can be had for the picking. It is seldom found for sale on any f tihe
markets, and the average housewife picks her guavas from whatever a
source she can obtain them. Probably the only well-established
rule governing the selection of guavas in Hawaii is that fruit from
the windward side of the island is inferior for jelly making to that otn
the leeward side. ..
COMPOSITION OF GUAVA JUICE. ... 3
To determine the composition of the juice of an average guaya t :3..
jelly-making purposes, 5 pounds of medium ripe guavas was coo i :.
in 2.5 pounds of water for one hour and then allowed to drain ;o .' .s..
night. When it was analyzed, the juice was found to have the fta )
lowing composition:
." ...i:" ":...:::..
TABLE 2.-Composition of guava jutc.G .

Constituent. ropor- Constituent.
Per cen. Pat. i
Sucrose.................................. L 0 Pectin (alcohol precipitate).............
Reducing sugars...................... 4.18 Acidity (as HSO4)..................
* Volume of drained juice, 1,200 cubic centimeters; Brix reading, 7.8.
The production of jelly from the juice of the guava is usually.en-
sidered an easy task. Experienced jelly makers, however, frequtnt 4by
have difficulty in getting a firm consistency, and jelly factr~fis 4
producing a uniform quality of jelly from guavas that have :-
' Methods of Analy of the Association of Official Agdiltural Chemists. Revised to Nov. 1,
Washlngton, D. C., 19f20 p. 153.






JTEILY MAKING WITH HAWAIIAN FRUITS. 5

#tmied from different localities. These differences have been
At ibuted to variations in the composition of the guava juices, which
Siariations in turn were thought to be due to the widely differing locali-
ties and seasons, as well as to varietal differences, individual varia-
.tions in the same variety, and varying stages of maturity of the fruit
when it was used.
SVariations due io widely differing localities and seasons.-To deter-
mine the effect of localities and seasons upon the jelly-making qualities
of .the juices, three guava-producing areas, representing widely
differing conditions of climate, altitude, and season, were selected
for study. Guavas from each of the areas were obtained from time
to time and their juices were partially analyzed.
A uniform procedure was maintained throughout the experiment.
II. In each test 5 pounds of medium ripe guavas were cooked with 2.5
pounds of water in an uncovered 2-gallon granite-ware container.
S After the mass had been constantly stirred to prevent it from sticking
to the container and gently boiled for an hour to effect complete
dissolution of the partly ripe fruit, it was allowed to drain overnight
in a double cheesecloth bag. Only the juice which drained through
without pressure was used in the experiment.
The moisture content of the fruit was determined by drying a
pulped sample to constant weight at 1000 C. Only the Brix corrected
figures, pectin number, and acidity of the juices were determined,
since the pectin and acid content are the only essential constituents
for jelly making. The variations in the sugar content of the juice
of a fruit are generally too slight to be of importance in this connection.
Table 3 gives the effect of localities and seasons on the composition
of guava juices.
TABLE 3.-Variations in the composition of guava juices due to location and season.

Juice.
Moisture __
Drained
Location.I Season. in Dj B ti
Me.e. Brix Pectin Acidit
Sguava. reading. No. (as HSW4)
S'Cubic
Windward Oahu: Per cent. centimeters. Degrees. Per cent.
Kailua...................... Aug. 22,1921 81.8 1,110 8.7 1 099
Do...................... Sept. 19,1921 85.3 1,180 8.0 9 L 10
Do.................... Oct. 4,1921 82.6 1,100 9.4 9) .82
Leeward Oahu:'
ano....................... Sept. 8,1921 86.5 1,130 8.1 7f L50
S* Do....................... pt. 16, 1921 83.3 1,180 8.3 8 L58
Do ....................... 22,1921 82.3 1,185 81 8 LO
Do....................... Nov. 8,1921 .......... 1,200 87 9 182
Pa'o ....................... Sept. 8,1921 .......... 1,490 6.9 8 L39
anas.....-................. 2,1922 .......... 1,205 7.0 7I L61
Mountain slopes:
Tantalus..................... Sept. 12,1921 83.6 1,150 9.2 81 L24
Do...................... 11 1922 87.8 1,415 8.4 7 1.
Do....................... Jan. 27,1922 87.0 1,200 7.7 6 L16
Do....................... Feb. 3,1922 87.5 1,210 7.4 7 L 6
The gnavas from Kailua, Manoa, and Palolo were composite samples that were taken from tonlots of
the Rmit. Those from Tantalus were picked from only a few trees each time.
s Elevation 100 feet.
SElevation 300 feet.
I Elevation 1,500 feet.
E.:
Table 3 shows that location has a very marked effect on the acidity
Sof the juices of the guava. The proportion of acidity in the juices of
S gnavas from the windward side of Oahu was less than 1 per cent,
while in fruits from the leeward side it averaged nearly 1.5 per cent.
The pectin content was highest in fruit from the windward side and
lowest in that from the mountain slopes, but it was sufficiently






BULLETIN 41,'. AWAIIw.~x1PEIrtilalk~. t---..,

high in all instances for jelly making. Thesuperioxity for j
of guavas from the leeward side over those from the wind
is undoubtedly due to the high acidity of the former.: -
The variations due to seasons are not outstanding, but
rainfall during the winter months increases the percentage o...
and decreases the pectin content in the guava.
Variations due to varietal differences.-Thompson a gives'
of six different varieties of guavas in Hawaii, one of which, t: e
berry guava, was found to contain more acid than the other Fat
although it is less acid to the taste. The only guava which gr
sufficient quantity to be of practical importance for jelly ni
the common guava, but for the sake of comparison the juices o*ltf
other varieties of guavas were tested. The results of the 'tes i
given in Table 4. .-:
TABLE 4.-Composition of juices from different varieties of guava. ,

Juice. "
Variety. in ---- --'
Moisture Drained : ......
guava. juice. Brix Sucrose Reducing Pectin, A
guava reading. rosesugars. No. (t i *

Per cent. centimeters. Degrees. Per cent. Per cent.
Sweet guava ............... 87.1 1,100 5.8 0.22 4.66 5 i
Strawberry guava 2......... 84.6 1,190 10.5 .................... 7
W white guava .............. .......... 1,160 10.3 .......... .......... 7
Common guava I........... 87.5 1,200 7.8 1.0 4;-4
1 Psidium guayava. 2 P.'catteianum. ":
1:..' 3."...:"
It is apparent from Table 4 that all of the varieties of guavyaim4 ]
contain sufficient pectin for jelly making, and that all, wit ,Jii
exception of the sweet guava, have sufficient acid for jelly maag.
Variations due to individual differences in the same variety--TI I
fruit from five guava bushes was kept in separate containers and thed
juices were compared. The bushes apparently were all of the comrn-
mon guava variety and grew in the same locality. The fruits selected '
from them were as near the same degree of ripeness as it was possible; ,
to select them. Table 5 gives the composition of the juices of the
fruits from five trees. :'...

TABLE 5.-Composition of guava juices from the fruits of five trees growingintin /~.:e
locality. ...
___________________________________* __*' : i-.- *,


No. of Drained Brix Pertin Acidity No. of
juice. juice, reading. No. Ha ). juice.
Cubic
centi-
meters. Degrees. Per cent.
1........ 1,040 9.9 81 2.19 4.......
2........ 1,050 9.2 74 1.16 5.......
3........1 1,240 8.4 71 1.09


'ectin A.lEM
No.


8.
Ti
ki-i *l
74 'a ..


Table 5 shows striking variation in the acidity of the firi 3
uniformity in pectin content.
Individual variations have but little effect where the fruit isj i
in ton lots. Variations in acidity would probably be rarth
where the fruit is gathered from only a few hushes. Unif ,
acidity results, when the fruits" are picked from a large a`i'3
bushes.
ar a.. i Sta. Rpt. 1914, pp. 64, 67.
'HBaaii Sta. Rpt. 1914, pp. 64, 67. ." "1 '|
"- i' ..:
r ,*






S JLY MAKING WITH HAWAIIAN FRUITS. 7

i aritions dfue to picking at different stages of maturity.-Two lots
M t avas were subdivided according to their stage of maturity and
Simt juice of each subdivision was analyzed. The composition of the
nices. is shown in Table 6.

t4LxE 66.-Composition of the juices of guavas which were used at different stages of
maturity.


Location.


Manoa:
Lot I...


Lot 2...


Stage of ripeness.


A; quite soft...........
B; full yellow; not soft......
C; greenish yellow; rather
frm.
[A; quite soft...............
C; g sh yellow; rather
firm.


1 Pectin numberX0.151Xcubic centimeters of drained juice divided by 100.

From Table 6 it is apparent that (1) the quantity of juice increases
as the fruit matures; (2) the pectin content of the juice decreases
with increasing maturity, while the total quantity extracted increases;
and (3) the proportion of acidity decreases very rapidly with increas-
ing maturity. The total quantity extracted decreases slightly with
increasing maturity in fruit of the lot 1 type and increases in fruit of
the lot 2 type.
These experiments have demonstrated that the pectin content in
guava fruit is uniformly high under all conditions, and that the acid-
ity is subject to wide variations. Only the sourest guavas possible,
with a good proportion of half-ripe fruit, should be selected for jelly
making, because juices of low acidity produce jellies of inferior
quality.
PROPORTION OF WATER TO FRUIT FOR GUAVA JELLY.

To 5-pound lots of fruit varying quantities of water were added to
determine the best proportion of water to use for the extraction of
juice. The results of the experiment are given in Table 7.

TABLE 7.-Composition of guava juices obtained by using various proportions of water
to 5-pound lots of fruit.

Pounds Juice.
of water
to Drained Total Total acid
5-pound Location. juice. Brix Pectin Acidity pectin extracted
lots of reading. No. (as ex* (as
guavas. tracted.? ISO04).
Cubic
centi-
meters. Degrees. Per cent. Grams. Grams.
2.5 A,Manoa.................... 1,130 8.1 75 L50 13.2 16.95
375 B Man......................--------- 1850 6.0 61 1.14 18.9 21.09
2.5 AManoa..................... 1 480 7.1 7 1.51 156 22.34
3.75 B Manoa...................... 1,985 6.0 6 1.13 18.0 22.43
5 CManoas...................... 2,390 5.5 51 1.03 20.7 24.62
2.5 A1Kailua.................... 1005 9.4 91 82 8 8.24
.75 B Kailus...................... 1,690 6.5 75 .83 18.5 14.03
5 C Kailua...................... 2110 5.5 7 .81 22.3 17.09

S 'Peafin number X0.15lXcubic centimeters drained juice divided by 100.
'Theigh visoesity of this juice is probably the cause of the lack of concentration of acid.
S43&892-23--2


Pectin
No.


Drained
juice.


Caubic
centi-
meters.
1,365
1,185
815
1.585
900


Bris
reading.


Degrees.
8.5
8.1
9.4
7. 1
8.5


Acidity
(as
113804).


Per cent.
1.39
1. 66
2.55
1.22
1.95


Total
pectin
ex-
tracted.'


Grams.
15.5
14.8
12.3
18.6
11. 5


Total acid
extracted
(as
H804).



Grams.
18.97
19.67
20.78
19.34
17.55










Kailua guiava,-.nd the total acid extracted "ii' e|
of over 5.pounds of water to 5 pounds of fruit woi, ... .....
crease the total extraction, but the "U~ie wtld bei
an extent that prolonged boili g would be required to
jelly. When the cost of fruit is an important item "it
vis able to use a greater proportion of water tha Ats; ter
even then a rebolimng of the pi~i, as is shown in the folo
graph, would be preferable.
SECOND EXTRACTION MW GUAVA JUICE
The guava pulp remaining after e:t* juice is drained. oi
thrown away. Guava butter can be made from the p- bW
never as much in demand as guava jelly. The jelly Talfitas,
heretofore treated a large part of the pulp as waste.
To determine whether a second cooking would produce .
sufficiently rich in pectin and acid to make jelly, the
remained after the first juice had been boiled for an hoir
drained was reboiled with water for 30 minutes an4 alowe t|
overnight in a cheesecloth bag. A third cooking produced
dark-colored juice which was not adapted to jelly m.. k
gives the composition of the juices of the first and seoi4bi
two lots of guavas. .:Ji
TABLE 8.-Composition ofjuices from guava which were boiled o c a d twic, ai

Juice ourc of mce Draied Brix. Pectin As d iy
No. juiee. .reading. No. ( aH

ceat- -. .. ,;1 ^
etels. Degrees. Per cedt. Qawb. i
A....... 5 pounds of fresh Kaiua gava.. 1,100 8.3 7 0.9T 12.5
B....... Pulp from AX1100 centimeters i
water .......-.....-----...... 8- 5.2 & 4'
C....... 5 pounds of fresh Kailna guava.. W90 9.2 8 L 04 ILl
D....... Pulp from CX1335 centimeters
i after ......................... 1,0 .6 7 .B 1
SPectin number X0.151Xcubic centimeters drained juice divided by 100. ...
Table 8 shows that juice resulting from the second extraw
contains almost as much pectin, but not nearly so high a propi~
of acidity, as does the juice of the first extraction.
A comparison of the total pectin and the total acid conte
A and B with those of C and D shows that the second extra
contains practically as much total pectin and acid as does t
extraction when the latter is very concentrated, as in C; and t
-total extraction in the second boiling is appreciably less wh
juice of the first extraction is sufficiently dilute, as in A.
Jellies of good quality were made from juices of the seo .
traction. As a rule they were darker in ctlor than thosa:i
extraction and did not possess as strong a guava flavor.
as high a sugar ratio as the juices of the first extraction W
when sufficient acid is added to the juice of the seconitl
SSecond-extraction guava juice is now being used by the
companies of Hawaii to meet the demand for.no
jelly. The only cost involved in pr;oducingyj
extraction juice lies in the additional 30 minutes reqlin
,ii. .ii ...!!!









Bul. 47, Hawaii Agr. Expt. Station.


-:


. S


j4l- "5i-'*


-"-1w


.a6-


;I*: x i I


FIG. I.-DETERMINING THE "PECTIN NUMBER" OF A FRUIT JUICE.


FIG. 2.-EFFECT OF VARYING PROPORTIONS OF SUGAR ( TO I' CUPS) UPON
THE AMOUNT OF JELLY PRODUCED BY I CUP OF FRUIT JUICE.


PLATE I.


i'*
1'









.... ......


"'
"" r


-""3



*i














.*.











p ortflions of sugar, pectin, an4.acid to use in making jelly.
ithwaite, working with a wide variety of fruits, warns
Suse of too much sugar. She considers 1 cupful of sugar
of juice to be -the best proportion for most fruits. Cruess
air,1 dealing with a number of California fruits, advocate
..f 1.5 pounds or more of sugar to 1 pound of fruit (equivalent
on of sugar to 1 cupful of juice). They found that jellies
consistency resulted from juices containing from 0.5 to 1.5
co. et citric acid (equivalent to 0.7 to 2 per cent sulphuric acid),
4,hat in the final jelly of good consistency the range of citric acid
T from 0.3 to 1.9 per cent (equivalent to 0.4 to 2.7 per cent
ric acid).
4 thwoite,e working with the apple, pear, peach, and grape,
4unded that an acidity greater than 0.5 per cent of the juice im-
Ar tbe quality of the jelly. Later on, she obtained excellent
i n currant and red raspberry juices having an acidity of
-J 1A09 per cent, respectively. Campbell 2 found that apple
a^ng pectin content of 1.25 per cent was necessary to pro-
i Aood commercial jelly, and that only 0.75 to 1 per cent was
to produce a jelly of delicate quality for household pur-
sarker,' working with apple cider, found that a satisfac-
e jelly could be made from juice containing 0.5 per cent of
ra iC .or more of pectin.
f event that the proportions of sugar, pectin, and acid can
..j.. wd,within rather wide limits in jelly making, not only with
i fr but bu also with a single fruit.
VARIATION IN SUGAR.
J4fuit B gives the results of tests with a jelly series obtained by
M addition of sugar in varying proportions to a constant proportion
ific from the common guava (PI. I, Fig. 2).

.--Reults of using ang ng proportions of sugar with a constant proportion of
S juice from common guavas.a

Propor- Specic, 'B g teg
tioen of gravity tempera- Cosisteney. Taste.
S' sugar. tare.

re. r cv. .C.
S 1 5.7 .1.27 102.5 Somewhat tough ....... Rather tart and strong flavored.
S341 58.7 1.28 10 Good; a trifle tough....... Tart; rather strong flavored.
-: B 62.8 1.28 10i 0 E0 xellent ................ Excellent.
4 6..4 7.3 1.29 104 O7 Exellent; somewhat mel- Excellent; mild.
.. .. low.
I .I-. L30 ~030 zxceellt; melow........ Very mild; sweet.
p! i.M 'h ,9 Ldl Poor-gaummny........... Toosweet.

gifuir BIa reading, .1; peetiiumIber, 7J; acidity (as Hs804), 1.19 per t.

M :;i, ,ma'.:^.i." r o. U IN
a fiWlsorkb tuetrn "!uwr ratio" dpiifes tecplsecpl of sugar added to I cuplo of juice.
I. ad ngmi n O.hm....:f"., 1 No.. p. "3..
i "1y o. p. 417.
e111 No. p. 457.
a se:9is g wia on .
P Hr;;; .















TABLE 10.-Results of using varying proportion of sugar with a
juice from t7dhe straw g.ava.1 "
____,_____"____^f


Sugar Weight
ratio, of jely.


GraIns.
244
306
376
445
468


Propor-
ton of
sugar.


Per cent.
61. 5
65.3
66.5
67.4
74. 8


Specific
gravity
T0c V


Boiling
temper-
ature.


SConsistency.3


. : ii.
^ n^


1I I ...... ...


1.28
1.30
1.30
L 30
1.332


*C.
103.2
194. 0
104.5
106. 5
106.5


Good; a trifle tough.......
ExceUmlt; rather firm.. ,..
Excellent; mellow...... '.
Fair; trifle gammy... ..
Thick siup............


Exesl : A:
Dett
"Swe t. 31 ..
. re et*. ;. .. .. ..:[ : .:: .


1Analysis of juice: Brix, 7.0; pectin number, 5; acidity (as BBO.), 0.99 cant. 1 PI
2 Reference to consistency "and "taste" clumnns M a jeysri ht the ra;tit
depends upon the quality of the jely desired. .

The following conclusions are evident from Tables 9 .ii.
(1) The maximum sugar ratio for the common guava iszykli
the strawberry guava,/ 1; (2) thw quantity of jelly icrea W
the increase in sugar ratio, but: the increase is n6t pro
(3) the percentage of sugar, as well as the specific g*avtyi
boiling temperature of the jelly, increase Vith the ~~mcre
sugar ratio; (4) the texture changes, with increasing a .
from tough to excellent, mellow, gummy, or sirupy, In
named; and (5) the jelly becomes gummy or sirupy when
portion of added sugar in the jelly is aboiit 68 per cent e.
(approximately 70 per cent total sugar), and it become!
when the proportion of added sugar is less than 60 per cent (a
mately 62 per cent total sugar).
Maximum sugar ratio of guava juices.-Table 11 gives in condes
form the maximum sugar ratio of a number of guava julea
determined by the foregoing method. r b!

TABLE 11.- Maximum sugar ratio of guava juice.a
:_. H I :


Source of
fruit.


Juice.


Brix
reading.


SDegrees.
Manoa...i 2.0
.. do-...... 5.5
...do......I 6.0
-..do......i 7.1
...do....... 7.2
...do .....i 8.5
...do..... 8.1


Acidity
(as
HS04).


Per cent.
1.32
L05
1.13
L51
L03
L39
L66


I Mai-
Pectino munm
No. sugar
ratio.


a The term "maximum sugar ratio" is used to denote the maximum number if oupfiLd
can be added to one cupful of juice to produce a jelly of good consistency:,,
u It is not claimed that the figures given in a ell series should be o Im fi
quantitative results. The personal factor undoubtedly enters to a considU M l
always been found possible to duplicate a series closely enough to draw s t i
The advantage of this method is that it affords a means of systmatially stuyqflitb V.h
in the sugar ratio.


No.
of
juice


No.
of
juice.


Juice.


Source of
fruit.


Manoa...
Kailna.. -
...do......
...do......
...do ......
...do......


Brix
reading.


Degres.
&87
4.7
6.7
5.5
6.5
S 9.4


Acidity
HSOl1).


Per cent.
1.32
.42
.72
.81
.83
.82


9


;4
.: :


" "'


*


_-;


i;
..
;.
;;.;
;;
;;;


";





JE. LY rK MAKING WITH HAWAIIAN FRUITS. 11

i i : m Table 11 it is apparent that there is a close relationship
een the Brix reading of the Manoa juice, the pectin number,
tt.Md the maximum sugar ratio. The sugar ratio is lower for the
K: ailua juices than it is for the Manoa juices due to the low acidity
i'of the former.
S Guava pectin table.-Table 12 has been constructed to give the
maximum sugar ratio of a guava juice when either the Brix reading
or the pectin number is known.

TABLE 12.-Guava pectin table.'

Maxi- Maxi- Maxi-
Brir Pectin mum Brix Pectin mum Brix Pectin mum
reading. No. sugar reading. No. sugar reading. No. sugar
ratio. ratio. ratio.

3.5 1 55-6.5 5- I 7.5-8.5 7-- 2t
S35-5.5 45 I 6.5-7.5 61-7t 2 8.5-9.5 89 2
1 The above table is based upon the data given in Table 11 on Manoa guavas. The use of the Brix read-
ing in this connection is not recommended because the relationship between the Brix and the pectin number
is not a constant one. It is not to be inferred that the maximum sugar ratio is recommended as the best
ratio. It merely indicates the maximum amount of sugar which will produce a jelly.

The juice should have an acidity of 1 per cent or more when the
guava pectin table is used. If the acidity is less than 1 per cent, the
maximum sugar ratio will be less. The texture of the jelly will be
improved, however, if the acidity is increased rather than the sugar
decreased.
Inversion of sugar.-In jelly making inversion of sugar is considered
necessary to prevent crystallization of the sucrose. The amount of
inversion required, however, has not been determined. Goldthwaite'"
failed to note any crystallization in jellies containing as low as 1.76
per cent or as high as 47.46 per cent of the added sugar inverted.
To discover the relationship between the sugar ratio and the
percentage of inversion, the invert sugar was determined in each of
several samples of jelly, the juice of which had the composition
shown in Table 13.

TABLE 13.-Composition of juices studied to determine the relationship between the sugar
ratio and the percentage of inversion.

Constituent. o Constituent. Po
portion. portion.

Per cent. Per cent.
8ucrose............. .... ....... ... 0.71 Pectin (alcohol precipitate)............. 1.06
Reducing sugar.......................... 3.01 Acidity (as H2804)..................... 1.54
u lour. Indus. and Engin. Chem., 2 (1910) No. 11, p. 459.
43822-23----3


I!
t'












'* X :.












TABLE 14.-Relation of sugar ratio to inmweon of0 ,spr. i '::il


oftime Weight sereose Su o rose in.
to. required of sr added in in- jelly
for jelly. to ie elly.4 verted.
cooking. i" je. jelly.2 (H204). y. ver .
____*_________ _L


Minutes.
81
61
6
5i
6
5


Grams.
177
261
335
397
467
536
584


Per cent.
61.64
60.96
62.42
65.26
66.19
66.99
70.05


Per cent.
57.48
58. 13
60.21
-63.41
64.61
65.62
68.79


Percent.
29.16
28.04
26.68
24.42
21.74
23.16
22.42


Per cent.
33.74
34.19
36.96
41.98
45.46
44.93
48.69


Per cent.
41.32
41.18
38.61
33.79
29.64
81.53
29.22


Per cent.
2.13
1.44
1.13
.95
.81
.70
.65


1.29
La
I.D
* 1.80
1.31


SAdded sugar plus total sugars of juice divided by weight of jelly.
s Added sugar plus sucrose of juice divided by weight of jelly.
a Invert sugar (Munson-Walker method) divided by weight of jlly.
(Percentage of invert sugar in jelly minus reducing sugars of juice) X0.95 subtracted from pas
of total sucrose added to jelly.
S(Percentage of invert sugar in jelly minus reducing sugars of juice) X0.95 divided by perceatta
-,,,,,, 11A tIriZl I 1 ." .. =.


ri'f


.UUL .um Uu. U[ J u Lu.*
S(Percentage of acid in juice X 245) divided by weight of jelly.

From Table 14 it is evident that inversion takes place ra
rapidly, only eight and one-half minutes being required to i
41.30 per cent of the sucrose and five minutes to invert 29.22 Ipe
The total percentage of invert sugar in the jelly resulting iM
sugar ratio of one-half is only 6.74 per cent greater than thaf W
sugar ratio of 2. It seems probable, therefore, that there is.:
cient inversion in the highest sugar ratios to prevent crystalliriut4z.

VARIATION IN ACIDITY. :.

To determine the effect upon guava jelly of varying the acdi fi
the juice, different quantities of citric acid were added to four portion i..
of the same juice in which the pectin content remained constariti.,
Tablel5 shows the variations in the jellies which were obtained fr oi2
each portion.


TABLE 15.- Variation in acidity of juice with a constant pectin content.a


ACIDITY OF JUICE, 0.72 PER CENT.


Acidity
of jelly
(as
HsSO4).b


Per cent.
0.74
.57
.48
.46


Consistency.


Firm; mellow..............................
.....do....................... ......
.....do..................................... ..
Poor; gummy...............................


7.
Taste. "


V .:;

Good.
Too sweet. ;
Rather sweet t. .
Do.
*u : isi


ACIDITY OF JUICE, 1.17 PER CENT.


0.72
.62
.55
.53


Excellent...............................
.....do ............. ....... ..............
Excellent; a trifle mellow...................
Poor; gtimmy...............................


Sugar
ratio.


Propor-
tion of
sugar
to jelly.


Weight
of jelly.


Grams.
237
305
364
375


I I I I r


Per cent.
63.3
65.6
68.7
80.0


63.1
65.5
68.0
73.9


* Analysis of juice: Brix, 6.7; pectin No. 6j; acidity (as H~SOO. 0.72 per cent.


a Analysis of juice: Brix, 6.7; pectin No. 6f; acidity (as HiSO4), 0.72 per cent.
b (Percentage of acd in juiceX245) divided by weight of jelly.
It No crystallization observed in any of the jellies after 6 months' standing.


Too tart.
Excellent.
Do.
Too sweet.


--


"ii '; :::
rf
: .. : : :
0 : /* H


"" :




\




-. --- ...... .... ---------- --------- -------------.......----------------- ---------------- -------------------------....... J -------------------------- -


W J


JELLY MAKING WITH HAWAIIAN FRUITS.


13


; w. a 15.-Variation


in acidity of juice with a constant pectin content-Continued.
ACIDITY OF JUICE, 1.4 PEIR CENT.


Propor- Acidity
SM o W .t tion of of jelly Consistency. Taste.
uatio. otjWiy. uuapr (as
to jelly. ESO4).

Grass. Per cet. Per cent.
i 518 67.5 0.66 Excellent.................................... Excellent.
2 595 67.2 .57 Good; a trifle mellow..................... Do.
21 652 69.0 .52 Fair: mellow; a trifle gummy................ A trifle sweet.
21 688 72.6 .50 Very mellow; sirupy ......................... Rather sweet.

ACIDITY OF JUICE, 1.62 PER CENT.

21 705 70.9 0.56 Poor; rather mellow....................... Rather sweet.


From Table 15 it is concluded that the maximum sugar ratio
increases with the acidity. A guava juice having a pectin number
of 61, which is a medium juice, requires an acidity of at least 1.4
per cent for the highest sugar ratio. When the acidity is less than 1.4
per cent, the pectin can not swell to its maximum capacity.
To produce a jelly of about the proper tartness, a juice of 0.71
per cent acidity requires a sugar ratio of about three-fourths; a juice
of 1.17 per cent acidity requires about 14; and 1.4 per cent acidity,
a sugar ratio of about 2.
Poor consistency results when the proportion of acidity in the
jelly is approximately 0.5 per cent or less. Although the acidity
can be much higher than 0.5 per cent without exerting a harmful
effect on the consistency of the jelly, the taste becomes tart when the
proportion of acid in the jelly is about 0.75 per cent or over. It
seems, therefore, that the optimum acidity in guava jelly is between
0.6 and 0.75 per cent of the jelly.

VARIATION IN PECTIN.

The effect of varying the pectin content of guava juice with a
constant proportion of acidity was studied by diluting portions of
a guava juice with different quantities of water and bringing them'
to a uniform acidity with citric acid.
Table 16 shows the composition of the juices in which the propor-
tion of acidity remained constant.

TA tE 16.-Composition of guava juices in which the pectin content was varied and the
acid content remained constant.


Brtx Pectin Acidity
Juice. reading. No. HO).
HSO4).

Degrees. Per eqt.
... ... ......... .............. ... .... ........... ......................2.6 1.40
....................................................................... 5.1 5) 1.40
... ............................................................. 7.9 7I 1.40


Y..1
: ." E
.r :.:. ,











TABLE 17.-Effect upon the jellies obtained from juices having a oir n
varying pectin contents.
JUICE A.

SPropor- Propor-
Suar Weght tion of tion of
fO.ofjely. tOsugar pectin Consistency.
I to jelly. in jelly .'i

Grams. Per cent. Per cent.
i 221 1 67.8 0.58 Excellent; tender.................... Too tart;
1 294 68.0 .44 Very tender.................... ...... Do.
It 346 72.3 .37 .....do................................ Tart;mild .
It 400 75.0 .32 Sirupy --............................ Good. ,;

JUICE B. ...:...
... .. ......
1i 401 62.3 0. 53 Excellent; tender...................... Tart.
1* 447 67.1 .48 ....do............................... Exeld a; ...
11 519 67.4 .41 Very tender......................... Exedla.nt;
2 569 70.3 .37 .....do............................ Excdlat;tw.wd 1
21 615 73.2 .35 Sirupy.............................. Toosweet.1, 4


..70.6 .4 Good... too ..ener Too .wee
......: .I .... .

(Petinnumber of juiceX63.7 245) divided by (.....................eight of jellyX 100)



From Table 17 it is concluded that (1) the maximum IM g S ar
increases with the pectin content; (2) a medium guava junce,
S538 65.1 .52.... ........................... .. .....



contains a pectin content of about......... 7 is capable of fr
2 637 70.6 .44 Good; too tender.................. .Toosweet. ".',,.



hav(Pecting a sugar ratio of juice 51245 divided by (wient acid is present .
From Table 17 it is concluded that (1) the maximum sugar
increases with the pectin content; (2) a medium guava juice,
contains a pectin content of about. 7j is capable of forming a
having a sugar ratio of 2, provided sufficient acid is present; ai|
the consistency becomes too tender for a good jelly when the proq|
tion of pectin in the jelly falls below about 0.48 per cent,
becomes tough when the proportion of pectin is about 0.7 per t
or over.
OTHER HAWAIIAN FRUITS FOR JELLY MAKING. A.F
Although there are many fruits in Hawaii that give pAt
jellies, the actual number which can be used for jelly
rather limited. Fruits that are commonly grown, such as the pa
the avocado, and the mango, are not adapted to jelly
"Papaya jelly" is occasionally made by adding pectin and .
acid to the papaya fruit. The mango contains sufficient pectin
acid for jelly making, but its yield is rather small to be of coM
cial use for jelly making, when the cost of the fruit and the
required to prepare the juice are considered.
Next in importance to the guava is the poha (Physalis pe
the jelly of which is much in demand. Commercial jelly Jcomp
in Hawaii are often unable to fill their orders for poha jelly, o
to the small quantity of poha fruit grown. The roselle (
sabdariffa) ranks third in commercial importance. This fruit
generallybe purchased on the markets during the fruiting
but & to its lack of popularity it is sold in small qua



t : .. ... .. ..






JELLY MAKING WITH HAWAIIAN FRUITS.


gIfII; from the Isabella grape (Vitis labrusca) is commonly made in
....b. home. This grape can be purchased on ,the markets nearly the
jouiir round. The poha, roselle, and Isabella grape, together with the
Cg ava, are the only fruits which are grown in sufficient quantities to
e of any importance for jelly making at present.
SThe methods worked out for the guava were used in making jelly
from the grape, the roselle, and the poha.

ISABELLA GRAPE (Vitis labruea).ts

A representative juice (juice B, Table 18) showed the following
analysis:

TABLE 18.-Composition of Isabella grape juice.

Constituent. tion. Constituent. Proper
tion. tion.

Per cent. Pe cent.
Sucrose.................................. .......... Pectin (alcohol precipitate) ............. 0.92
Rednu ng sugars......................... 10.18 Acidity (as H S 4).--...........-......... 1.21


Proportion of water to fruit for grape jely.-To determine the best
proportion of water to fruit, three 10-pound lots of grapes were
cooked with varying proportions of water. Gentle boiling was main-
tained for only 20 minutes, during which time complete disintegra-
tion of the fruit had taken place. Each lot was then strained through
cheesecloth, after which the pulp was squeezed to remove any
remaining portions of the juice.
Table 19 shows the composition of grape juice made with different
proportions of water and fruit.

TAsBL 19.-Composntion of grape juices resulting from varying proportions of water
and fruit.

Pounds Total
f water total Brix Total Petin Acidity Total acid ex-
Juice to 10 Total Brix Total Pectin (as pectin tracted
pounds juice. reading. sugars. No. SO4). extracted (as
grapes. HiSO4).

Cubic cen-
Pouds. timeters. Degrees. Per cent. Per cent. Grams. Grams.
A ................... 0.5 3,140 15.2 11.91 51 1.37 36.6 43.00
............... 3.0 4,055 12.6 10.18 4t 1.21 38.2 49.07
.... ........... 6.5 5,350 10.1 8.07 31 .95 38.6 50.83

.1 ectin number X0.222Xcubic centimeters juice divided by 100.

A') study of Table 19 shows that there is nothing to be gained in
Aiddiig more than 3 pounds of water to 10 pounds of grapes, because
a greater amount does not result in appreciably greater extraction.

3 The Isabella variety has shown remarkable adaptability to the climatic and soil conditions of Hawaii
lfr m~rpasses all other varieties in acreage. It is usually spoken of as the Hawaiian grape.


,. .i!L ." v
S[I!!:" ^
111!"-" t *i ^ '


15











a jelly series on each of the juies giveHn in. T.b .J F[ s

TABItE O2.-Results of nMrying- prpartiW of saew, pectin,, st "aif ""

yUTCE 'A. i
_____________ __________ _____ __________ __ ^-.L'I j~g


Pro-
por-
tion
of


Total
sugar
in
jelly.


Spe-
cific
grav-
ity
80oC.


Boil-
tng
tem-
pera-
tures.


i Pee-
tin
in
jellyi


in
iley.


t :: q


Consistency.
; -: :


" 1 .1 ..
Tatv


Min. Gms. P. ct. Pc. t. .C. P. P. c'.
1 3 342 43.8 52.4 1.21 102.0 0.83 0.98 Firm; tender ...... Too tat.
1 2 378 52.9 60.6 1.25 103.0 .76 .89 .....do ........ T11.----. .
I 31 432 57.9 64.6 1.27 103.5 .66. .78 ...do.............. Exelle.
4 5 481 62.4 68.4 1.27 104.0 .00 .70 .... do--........... i,
11 6 536 65.3 70.7 1.29 105.5 .53 .63 Mellow; lacks body. Rather sawei
2 7 608 65.8 70.6 1L28 105.5 .47 .55 .....do-...-...... ... Sweet.


JUICE B.
R."t::; .'(A .


52.7
.54.6
59.4
67..4


61.4
61.5
65.3
73.0


1.25
1.25
1.27
1.29


103.0
103. 5
10&.0
1009


0.82
.63
.55
.52


1.04
.81
.70
.67l


Firm; tender......
.....do.---..,....,-
.....do ....... ......
Mellow; Wks bodyJ


Tart.
,4=000 -:i
.B-^ eS
.. ? ....*>. i .. .; :: ..


JUICE C.


F n i..~ r;:-~z ;;*;;;ii
n;;;;i
; ;
i~litlin:f:
'''I
*' ;


1 8 222 45.0 3. 9 1.22 103.6 0.80 1.05 firm tender..._ -.IdU4
. 6J 266 56.4 63.8 1.26 104.5 .66 .88 .....do ........ El .;
1 s 327 61.2 67.2 1.27 104.5 .54 .71 d.....do............
S 6 375 66.7 71.9 1.29 10.0 .47 .62 Mellow: lacks body, ..


SThese jellies were left exposed to the air. All jellies having a sugar ratio of less than 1 dieveopsd !
Those having a sugar ratio of 1 or more did not develop mold in 3 weeks' standing. No crysta.i0i0
occurred in any of the lots.
I (Pectin number of juice X0.222X245) divided by (weight of jellyXl00).
3 (Per cent acid in juice X245) divided by weight of jelly.


From Table 20 it is evident that (1) the maximum sugar ratios of
juices A, B, and C are 14, 1I, and 1, respectively; (2) the minimuia
proportion of pectin necessary to produce a jelly with sufficientL body
is about 0.56 per cent of the jelly; (3) the acidity of grape juice. iI:
probably never the limiting factor in jelly making since th be
flavors were produced with acidities of from 0.7 to 0.85 per cem a::i
the jelly; (4) the jelly either lacks body or is of a mealy, gran r
texture whenever the total sugar in grape juice is about 67.0 per c :!nt
or over, and mold is likely to develop when the total sugar is16.
than about 60 per cent; and (5) the maximum sugar ratios if 11iW
rape juices, as determined by the above table, are about one-fowt
power than is given in the guava pectin table for the same "oep|ij
numbers.


NOTES ON JELLY MAKING FROM THE ISABELLA GRAPE.


.:7
4,: N. .. .:::
1 N: .** ...


Grape jelly is characterized by its very tender texture. Ovs,1
cooking guava jelly results in a tough, hard consistency, but ovis. '
cooking grape jelly causes an apparent breaking down of the pectia,
which becomes a soft, granular mass. Grape jelly should not, there*
fore, be "overcooked.


.. '. -
,;;
.. .':"" "'3 .:


Sugar
ratio.


Length
of
time
re-
quired
for
cook-
ing.


Weight
of
jelly.


285
366
4245
445


- a bbd-rh-


i r."





JawLY MAKING WIHr HAWAIIAN FRUITS. 17

S Pi 1o high a sugar ratio shows itself in lack of body, the jelly
y "meltig in one's mouth." Undisturbed in the glass, this
may have the excellent sharp cleavage of a perfect jelly, but
2 from its mold, it falls apart; or in other words, it has failed
to jell.
Oape jelly should be made in small batches in a relatively large
ii ainer so that evaporation will be rapid. Mealy or granular
texture was found to result when the jelly was allowed to boil over
10 minutes.
All the grape jellies showed -considerable tendency to "weep"
6gardless of the sugar ratio. "Weeping is doubtless due to the
weak .nature of the colloidal membrane of the grape pectin. This is
substantiated by the fact that adding a small amount of apple pectin
Stogrepe jelly will not only stop "weeping" but also greatly strengthen
the texture. of the jelly.
S. ROSELLE (Hibiscus sabdariffa).

; Analysis of roselle juice.-Analysis of representative roselle juice
U nice D, Table 21) gave the following results:
TABLE 21.-Con position of roselle juice.
Propor- Propor-
Constituent. P Constient. Propor-
't.n -Ition.

Per cent. Per cent.
S......................................... Pectin (alcohol precipitate)-..-.......... 0.95
Sgs. n ................... .... 0.21 Acidity (as H SS04)...................... .91

S. portion of water to fruit for roselle jelly.-Varying amounts of
S Iper were added to five 3-pound lots of roselle to determine the best
a tio of water to fruit from which the seed pods were not removed.
Gentle boiling was maintained for 20 minutes, when it was found
that the calyxes had completely disintegrated. Each lot was then
strained through cheesecloth-and squeezed as dry as possible.
Table 22 gives the composition of roselle juices made from varying
proportions-of water and fruit.

T x 'jl 22.-Composition of roselle juices resulting from varying proportions of water
and fruit.

Pounds Total
of water Total Brix Pectin Acidity Total pee- ad ex-
[nice. to3inex-
JI ::: ice. p~o i juice. reading. No. t (s-
pounds H1SOM). trated.1 "tad(as
roselle. HSO04).

Cubic
.. ......................... 3 .......... .......... .................... .......... .........
.*II.L. Po.unds. cetdrs Degrees. Per cet. GraIns.. ra,'s.
: : ; ......................... 5 1, 5. 1.17 19.3 19.42
-.......................... 6 2.120 4.3 6 .98 23.7 20.78
.i : .:...:......... ............. 7.5 2,980 3.8 5 .85 27.7 25.33
:- ... .... .- ...... 9 3,730 3.1 4 .74 29.5. 27.60

i, u i-n ..ber. XOJAiXcubtn ceatimeter ofjuice divided by 1OO.
I" I::: ** hie fdrmied a senijelly and would not pass through the cheesecloth bag.








extraction of pectin and acidity incres and thia lt i
greater than that of juice D the pectin and acid conte Nai
that the juice can be sufficiently concentrated for jelly
by prolonged boiling.
Composition of different parts of the rosele plant.-Wester..
that the leaves and stalks of the roselle can be used for jelly
and recommends the removal of the seed pods from the"
before cooking.
To learn whether these statements are applicable to the rb
Hawaii, it was decided to experiment by separating a .in l
roselle plant into three portions; (1) the mature fruit; (2).th '
ture fruit, blossoms, leaves, and tender ends of the. stem; ~
the remaining woody stalks. The mature fruits were then sepp lAd..i
into calyxes and seed pods.
The juices, the composition of which is given in Table 22, wore 'i
prepared as follows:
A. Calyxes weighing 1.91 pounds were separated from 3 p.andp s:of.i
mature fruit and boiled with 4.5 pounds of water for 20 minute.:
The mass was then drained through a cheesecloth bag and squeeei
as dry as possible.
B. Seed pods weighing 1.09 pounds were extracted from 3 ounids,
of mature fruit and boiled with 4.5 pounds of water for 20 mi~t s:sL l
The juice was then completely drained and boiled down.
C. Three pounds of mature fruit from which the seed pods--awe:i
not removed were treated like that of series A.
D. The immature blossoms, leaves, etc., of a single roselle pel I]
weighing 0.93 pound, were chopped fine, boiled with 2 pounds of-
water for 30 minutes, and the juice was completely drained off.
E. The stalks, immature blossoms, leaves, etc., of a single roaslle
plant, weighing 0.98 pound, was cut into short lengths and boilJ-S
with 2 pounds of water for 30 minutes, after which the juice waiS
completely drained off. :
Table 23 gives the results of analysis of the roselle plant. .I
STABLE 23.-Composition of the roselle plant. iI'

Total Brix Pectin Acidity T
Parts of individual plant. jToal redi Pti Acidt ta
juice. trading. No. (as tin ei'
HiBOS). tracted.iL
-------------------- ----- ----- ----- ------ A. ",. ^ ;:.^*
Cubic
centimders Derees. Pr cent. Grams. hu
A, Calyxes.............................. 1,700 2.7 4 0.78 13.4
B, eed pod.....--..................... 315 3.4 2 .34 1.2 .i
C,Whle fruit........................ .. 1,680 34 4) .84 14.9 ..1
D, Leaves, stems, etc. .................... 660 3.2 2) .64 3.1 L4.
E, Large stalks ....... ................. 610 1.3 () .10 ..........
Pectin number X0.18BXcubic centimeter ofjuice divided by 100.
Immature blossoms, leaves, etc. of a single plant.
STrace.
From Table 23 it is apparent that the calyx of the roselle, a'.
grown in Hawaii, is the only part of the plant containing sufficieiil
pectin and acid to make it of value for jelly making. The lehavYBij
tender shoots, and immature calyxes do not contain sufficient pecti:t:!
Prog. Agr., 5 (1921), No. 7, p. 18.






JELLY MAKING WITH HAWAIIAN FRUITS. 19

to make them practicable for use in jelly making, and the flavor of
t4i e jlly made from them was not appetizing, although it had an
e :".eIent consistency.
., ellies made from the calyxes and from the whole fruit were com-
i pared for taste and consistency. It was impossible to detect any
difference, and since the separation of calyxes and seed pods is a
rather tedious process, the operation seems a needless expenditure
of time.
Sugar ratio for roseUe jelly.-Table 24 gives the results obtained
From a jelly series made from juices B, D, and E.
TAint.E 24.-Results of varying proportions of sugar, pectin, and acid in roselle jelly.

JUICE B (seed pods).

Bug- Propor- Propor- Acidity
ar Weight tion of tion of of ily Consistncy. Taste.
ra- of 31ly. sugar to pectin
S to. jelly.I in jelly. HSO4).

Grams. Per cent. Per cent. Percent.
.1 316 63.3 0.90 0.91 Good; firm; tender.......... Rather tart; strong flavor.
It 391 63.9 .73 .74 .....do...................... Do.
1* 460 65.2 .62 .63 Excellent; firm; tender...... Excellent:strong flavor.
1 505 69.3 .56 .57 .....do....................... Excellent.
2 552 72.5 .52 .52 Too mellow.............. Too sweet; mild.
Sl 597 75.4 .48 .....do................... Toosweet.

JUICE D (leaves, stems, etc.).

S68 73.5 3.34 ; 3.06 Thick sirup.................. Too tart; strong flavor.
:157 63.7 1.45 1.33 Fair; rather sirupy........... Do.
S 231 65.0 .98 .90 Good; firm; tender........... Tart.
01 66.4 .75 .69 Excellent; firm; tender....... Excellent; mild.
365 68.5 .62 .57 Excellent.................... Do.
S 410 73.2 .55 .51 Slightly lacking in body...... Do.
S 449 77.9 .51 .46 Lacking in body............. Too sweet.
520 77.0 .44 .40 Sirupy...................... Do.


JUICE E (large stalks).

l 218 68.8 .89 .83 Firm; tender................. Excellent; tart; mild.
1 287 69.7 .6 .63 .....do...................... Do.
S 1 334 74.8 i .58 .541 Too mellow............... Excellent; mild.
381 78.7 .51 .48 Sirupy..................-.. Do.

I The proportion of total sugars in the jelly was not determined, since the fruit sugars in roselle juice are
negligible.

S ..From Table 24 it is concluded that (1) the maximum sugar ratio
of juices B, D, and E is 1 It, and 1, respectively; (2) roselle jelly
'containing about 72 per cent of sugar, or over, lacks body, or is sirupy
and that containing less than about 63 per cent is of very poor
consistency; (3) the minimum pectin content necessary to give
S tIhient body to roselle jelly is about 0.63 per cent of the jelly;
4 l the best flavors are produced from juices having from 0.5 to 0.7
per cent of the jelly; and (4) the maximum sugar ratios, as deter-
'nmined by Table 24, are about one-fourth lower than is given in
;-the guava pectin table for the same pectin number.






20 BUILTEU 0N, V.HAWwAI nw nPBMBTSA .-irnn S r

NOTiE ON JELLY XAlrIMG FPROILM OlIB E.
Roselle jelly is comparatively easy to make'. h' '
may have sufficient body, the mass should be boiled f
after the first jelly test is made. A precipitate Upro
stiff guava jelly will produce a roselle jelly of proper
Roselle jelly somewhat resembles grape, jelly 'n it tet
sistency. However, it does not "weep" to the extent tlthiL
does.
The flavor of the roselle is very strong. Jellies that aret
too concentrated a juice, or which contain too small an
sugar, have a very strong flavor and a deep red color. This ii
ably the chief cause of the lack of popularity of the roself p
If a medium juice-that is; one containing about 2.5 pounds of
to 1 pound of fruit-and the maximum sugar ratio are used
resulting jelly will be milder flavored and lighter colored..
POHA (PhysaHl perviana).

Analysis of poha juice.-Juice of the poha had the folloewine aCi
position:
TABLE 25.-Composition of poha juice. -

Constituent. PopW- Constituent. -:

Per cent. if
Sucrose....................... .......... 2.72 Pectin (alcohol precpitate)......., .4
Reducing sugars........................ 10.42 Acidity (as H 04) .................. .

Proportion of water to fruit for poha jelly.-Varying amount.
water were added to 10-pound lots of poha to determine the bt
proportion of water to fruit. Gentle boiling was maintained f'
20 minutes when it was found that complete disintegration l id
taken place. Each lot was then strained through cheesecloth wad:'
squeezed dry.
Table 26 shows the composition of juices obtained with r
proportions of water and fruit.
"" ..'i". I:... ....
TABLE 26.-Composition of poha juices resulting from varying roportiowwedfy i
fruit. .. ......

Total I
Pounds of water tb 10 pounds Total Brix Total Pectin Aidity n
of pohas. juice, reading. sugar. No. H ). tS :.i



Meters. .DeDres. Per cent. Per cent. .Graws.
A (none)............ ........ 2, 410 18.9 15. 4 1.65 1I.
B (1.5).......... ............ 3 0410 I7 13.12 S 1.45 t 1L8
C (4) ........................ 3,73 13.3 1L1l 3 L10 1.9.
SPectin number XO.172Xcubic centimeter of juice divided by 10. '



'4ii


.. A






.TEILY MAKING WITH HAWAIIAN FRUTS. 21

I:::i n examination of Table 26 shows that the best ratio of water
i ntuifft was 1.5 pounds of water to 10 pounds of pohas. Extrac-
Sii -WM then practically complete. With the higher dilutions the
l: t content was too low for a good jelly juice.
SS'ugar ratio for poha elly.-Table 27 gives the results obtained
f: a jelly series made from juices A, B, and C of Table 26.

:: TABLE 27.-Results of varying proportions of sugar, pectin, and acid in poha jelly.
JUICE A.'

Proper- ,rPropor -
Weight AP Tbtal Po tof
I O of- o s in o i Bity Consistency. Taste.
jelly. to jelly. injelly- in jelly. (as

Srams. Per cent. Per cent. Per cent. Percent.
S1 : 338 5.2 70.6 0.53 1. 2 Firm; somewhat tough..... Tart; strong flavor.
S394 63.5 73.3 .45 1.03 Fim; excellent............. Fair; strong flavor.
455 65.9 74.4 .39 .89 .....do .................... Excellent.
.M' 68.6 76.2 .35 .79 Firm; tender............... Excellent; rather
sweet.
2 541 74.0 81.1 .33 .75 Fird, but gummy ........... Rather sweet.

; JUICE B.2

: 248 60.5 73.5 0.60 I1.43 Firm: somewhat tough..... Tart.
1 323 61.9 71.9 .46 1.10 Excellent ................... Excellent.
i i 388 64.4 72.7 .38 .91 ......do ....... .............. Do.
S 438 6. 5 75.8 .34 81 Excellent; tender........... Do.







P r I arL colored and rather strong fvored series.
:...." JUICE C.2





I Dark colored and rather strong flavored series.
i A 2 of juice prevented a higher sugar ratio. However, the tender consistency of the I sugar ratio-
r ti:eated that a higher ratio would produce a gummy or sirupy jelly.

.. .. From Table 27 it is concluded that (1) the maximum sugar ratio
r ju ices A, B, and C is -1, 1, and 11, respectively; (2) poha jelly
S~imu ch higher in sugar content than is any other jelly studied;
l f;a elly of excellent consistency and taste will result when the
I tal asuar content is from 70 to 75 per cent, but the jelly will be
to g n the sugar ratio is less than 70 per cent, and gummy or
pnpy when the sugar ratio is over 75 per cent; (4) the minimum
p ortin of pectin required to produce a good consistency is about
SK ;; (5) the acidity of poha juice is probably never a limiting
ctor, but the best favors were produced with acidities ranging from
S0.8 to 1.0 per cent of the jelly; and (6) the maximum sugar ratio
I the poha'uies, as determined by the above table, are one-fourth
a:: z-lnt amg hier than is given in the guava pectin table for the
9 .e'Pectin numbers.
.. ... ...






. BUILETJIN 1.. ...WL. i....W.W.1 #+,


NOTES ON JELLY MAKING FROM :THfE FOHA.,:
1. 0 .. ",,iM" : .... ... .:..
It was found rather difficult to produce a poh6' JelyMl.
proper consistency. This is due to the fact ta th t
product becomes entirely too firm and tough when t'l
allowed to cook until a test, suitable for guava jelly, liCll
A very soft jelly test must be used to produce 'a' god, ~; tiii :
:sistency.
Owing to its very high sugar content, poha jelly has a ..
to crystallize. If the jelly is covered with paraffin, or hermet
-capped, crystallization can usually be prevented. *
CONSISTENCY OF JELLIES AS AFFECTED BY THE PHYSICAL PR-
OF PECTIN.
A fruit jelly is essentially a colloidal gel, throughout which sil
and acid cause a uniform precipitation of the pectm. The char]i ttu
of the resultant gel depends primarily upon the physical proptib f i
-of the pectin. Extensive studies have been made of the occi nei I
extraction, and chemical composition of pectins.0 Little m .etia ..i
however, has been made of the difference in their physical propertiis,:3
which, from the standpoint of jelly making, is of very great important&.
Observations on the physical difference in the alcohol precipitate.
.of the four fruit juices (grape, roselle, guava, and poha) studied .....'
the writer show that the properties of jellies are closely related: t
the physical properties of their pectins.
Table 28 shows the relation existing between the physical pj
erties of pectins and the resultant jellies. .. .............:.i::.i,:i
TABLE 28.-Relation of the physical properties of pectins to the resultant jellies.

Fruit. Pectin. Jelly.
-- -.------ ... -'
-Grape..... Very weak pectin; very short fibers; pectin Tendency to weep; easily destrpiyed b
mass easily broken apart. heating; low sugar content; fttn er :
body. .. .. ,
Roselle.... Weak pectin; short fibers; pectin mass easily Tender; lacks body. :
broken apart. .
Guava.... Strong pectin; long fibers; pectin mass spongy Dense; plenty of body; tough, if os i:a
and tenacious.
Poha...... Very strong pectin: very long, dense fibers; Very dense jelly; plenty of body; ^ i B
pectin mass tough and stringy. if overcooked; high sugar content.

Table 28 indicates that there is a gradation of the physical'
erties of the pectin and jelly from grape through, to, and inl
that from poha. The pectin gradually increases in length [i
and tenacity from the gelatinous grape, pectin to the dense I"
poha pectin. The jellies increase in body and density fnt i
tender grape jelly of low sugar content to the tough poha jeiW
high sugar content. It seems, therefore, that the physical: bha&t
of the pectin is an important factor in determining the coriist
of jelly. .
APPLICATION OF THE GUAVA PECTIN TABLE TO OTHER FRUIT, JU~E~ c S.
Reference of the pectin numbers of roselle, grape,-and plohi d_!
to the guava-pectin table shows that the maximum sugarat'ril fiB
the roselle and grape juice is too high by one-fourth and that
S2 U. S. Dept. Agr., Bur. Chem. Bul. 94 (1905), pp. 67-89.


212





JELLY MAKING WITH HAWAIIAN FRUITS.


r Im sugar ratio for poha juice is too low by from one-fourth
i'M half. These discrepancies are probably due to the physical
min the pectins of the fruits.
the physical differences are taken into consideration, the pectin
r I for guavas can be applied to most fruit juices. If the pectin
tate forms a tender mass that is easily broken apart when
in number of unknown juice is being determined, one-fourth
of sugar should be subtracted from the maximum sugar
l4x~o as determined by reference of the pectin number to the guava-
I tin table. If the mass is very dense and tenacious, one-fourth
ul;p.fl. should be added to the maximum sugar ratio.
SUMMARY.

SiJelly making from tropical fruits is as yet an undeveloped industry.
'l -S'.he writer conducted a series of experiments for the purpose of
Developing a systematic procedure for making jelly from any kind
i of fruit containing sufficient'pectin and acid.
SA method is proposed for determining the "pectin number" which
can be reduced to the approximate per cent of pectin by means of a
common factor.
A table of the maximum ratio of sugar to guava juice is given for a
Series of pectin numbers. The table may be used for other fruit
juices provided the character of the pectin is taken into account.
Experiments were made with the guava, grape, roselle, and poha
to determine their value for jelly making.
The guava is especially well adapted for jelly making. It contains
a strong, fibrous pectin, and usually has sufficient acid. The best
Proportion of water to guava is 0.75 pound to 1 pound of fruit. This
produces a juice of 6 to 7 pectin number and 0.8 to 1.14 per cent
Acidity. The maximum sugar ratio for such a juice is 1 to 1i.
Location, altitude, season, variety, and differences in the same
Variety have a very marked effect on the acidity of guava juices.
The pectin content of all guava juice is uniformly high. It is con-
eluded, therefore, that acidity is the only important variable in guava
juices and that failure to make jelly from the guava is directly trace-
able to lack of acidity in the juice.
The Isabella grape contains a very weak gelatinous pectin. It
I usually has sufficient acid for jelly making. The best proportion of
Sweater to fruit is 0.3 pound to 1 pound of grapes. This produces a
Sjuice of 4- pectin number and 1.21 per cent acidity. The maximum
sugar ratio for this juice is 1}.
S The roselle contains a rather weak, short-fibered pectin, but the
Soportion of both pectin and acid is sufficient for jelly making.
SThe best proportion of water to roselle is 2.5 pounds to 1 pound of
fruit. This produces a juice with a pectin number of 5 and an acidity
: of 0.85 per cent. The maximum sugar ratio for this juice is 11.
SThe only part of the xoselle from which jelly should be made is the
|t calyx. Leaving the seed pods in during cooking does not affect
the flavor.
I, The poha usually contains a very dense, long-fibered pectin. The
PProportion of pectin is quite low, but the acidity is usually high.


23






24 BUTLErIZ 47, HAWAIIr j InPEMEawar. -

The best proportion of water to pohas is 0.105 pound (.
fruit. This produces a juice with a pectin number-of 8
of 1.45 per cent. The maximum sugar ratio of this jmnW
Jellies of good consistency and flavor were obtained m*wi
lowing variations in sugar, pectin, and acid contentof o l
Guava jelly between 0.48 and 0.7 per cent pectin, Q0. andO
cent acid, and 60 and 70.per cent sugar; grape jelly, .0.66
pectin, between 0.7 and 0.85 per cent acid, and 60 and 7 e
sugar; roselle jelly, 0.63 (minimum) pectin, between-0.5 A:
cent acid, and 63 and 72 per cent sugar; poha jelly, 0.35 (
pectin, between 0.8 and 1.0 per cent acid, and 70 and 75 Peti
sugar.
The consistency of a jelly is determined to a large extent by tS ;
physical properties of its pectin. A gelatinous, short-fibered peMtia
produces a weak, tender jelly, such as is obtained from tdi griapee
roselle, while a dense, long-fibered pectin produces a denOse, eirt4i l
textured jelly, such as is obtained from the guava or poha. '.











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