JELLY MAKING WITH HAWAIIAN FRUITS. 
9 
EFFECT OF VARYING PROPORTIONS OF SUGAR, PECTIN, AND ACID IN 
JELLY MAKING. 
Considerable difference of opinion exists among investigators as to 
the best proportions of sugar, pectin, and acid to use in making jelly. 
X. E. Goldthwaite, 9 working with a wide variety of fruits, warns 
against the use of too much sugar. She considers 1 cupful of sugar 
to 1 cupful of juice to be the best proportion for most fruits. Cruess 
and McNair, 10 dealing with a number of California fruits, advocate 
the use of 1.5 pounds or more of sugar to 1 pound of fruit (equivalent 
1.75 cupfuls of sugar to 1 cupful of juice). They found that jellies 
of good consistency resulted from juices containing from 0.5 to 1.5 
per cent citric acid (equivalent to 0.7 to 2 per cent sulphuric acid), 
and that in the final jelly of good consistency the range of citric acid 
varied from 0.3 to 1.9 per cent (equivalent to 0.4 to 2.7 per cent 
sulphuric acid). 
Goldthwaite, 11 working with the apple, pear, peach, and grape, 
concluded that an acidity greater than 0.5 per cent of the juice im- 
paired the quality of the jelly. Later on, she obtained excellent 
jellies from currant and red raspberry juices having an acidity of 
2.417 and 1&09 per cent, respectively. Campbell 12 found that apple 
juice having a pectin content of 1.25 per cent was necessary to pro- 
duce a good commercial jelly, and that only 0.75 to 1 per cent was 
necessary to produce a jelly of delicate quality for household pur- 
poses. Barker, 13 working with apple cider, found that a satisfac- 
tory apple jelly could be made from juice containing 0.5 per cent of 
1 per cent or more of pectin. 
is evident that the proportions of sugar, pectin, and acid can 
be varied within rather wide limits in jelly making, not only with 
different fruits but also with a single fruit. 
VARIATION IN SUGAR. 
Table 9 gives the results of tests with a jelly series M obtained by 
the addition of sugar in varying proportions to a constant proportion 
of juice from the common guava (PL I, Fig. 2). 
Table 9. — Results of using varying proportions of sugar with a constant proportion of 
juice from common guavas. a 
Sugar 
ratio. & 
Weight 
of jelly. 
Grams. 
269 
341 
398 
446 
512 
584 
Propor- 
Specific 
Boiling 
tion of 
gravity 
tempera- 
sugar. 
80° C 
ture. 
Per cent. 
° C. 
55. 7 
1.27 
102.5 
5-. 7 
1.28 
103. 5 
62.8 
1.28 
104.0 
67.3 
1.29 
104.7 
68.5 
1.30 
105.0 
70.9 
l.*l 
106.0 
Consistency. 
Taste. 
Somewhat tough 
Good: a trifle tough 
Excellent 
Excellent; somewhat mel- 
low. 
Excellent; mellow Very mild; sweet 
Poor— gummy Too sweet . 
Rather tart and strong flavored. 
Tart: rather strong flavored. 
Excellent. 
Excellent; mild. 
«• Analysis of juice: Brix reading. 8.1; pectin number, 7£; acidity (as H2SO4), 1.19 per cent. 
b In all of this work the term " sugar ratio" signifies the cupfuls of sugar added to 1 cupful of juice. 
9 /our. Indus, and Engin. Chem., 1 (1909). No. 6, p. 333. 
!<> Jour. Indus, and Engin. Chem., S (1916), No. 5. p. 417. 
11 Jour. Indus, and Engin. Chem., 2 (1910). No. 11, p. 457. 
» Jour. Indus, and Engin. Chem., 12 (1920), No. 6. p. 568. 
13 Jour. Soc. Chem. Indus., 37 (1918). No. 14. p. 245. 
M The procedure for obtaining a jelly series is given on p. 3. 
