.JELLY MAKING WITH HAWAIIAN FRUITS. 23 
maximum sugar ratio for poha juice is too low by from one-fourth 
to one-half. These discrepancies are probably due to the physical 
differences in the pectins of the fruits. 
If the physical differences are taken into consideration, the pectin 
table for guavas can be applied to most fruit juices. If the pectin 
precipitate forms a tender mass that is easily broken apart when 
the pectin number of unknown juice is being determined, one-fourth 
cupful of sugar should be subtracted from the maximum sugar 
ratio, as determined by reference of the pectin number to the guava- 
pectin table. If the mass is very dense and tenacious, one-fourth 
cupful should be added to the maximum sugar ratio. 
SUMMARY. 
Jelly making from tropical fruits is as yet an undeveloped industry. 
The writer conducted a series of experiments for the purpose of 
developing a systematic procedure for making jelly from any kind 
of fruit containing sufficient pectin and acid. 
A 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 H to If. 
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- 
cluded, 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 
usually has sufficient acid for jelly making. The best proportion of 
water to fruit is 0.3 pound to 1 poimd of grapes. This produces a 
juice of 4^ pectin number and 1.21 per cent acidity. The maximum 
sugar ratio for this juice is 1J. 
The roselle contains a rather weak, short-fibered pectin, but the 
proportion of both pectin and acid is sufficient for jelly making. 
The 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 1^. 
The only part of the .roselle from which jelly should be made is the 
calyx. Leaving the seed pods in during cooking does not affect 
the flavor. 
. The poha usually contains a very dense, long-fibered pectin. The 
proportion of pectin is quite low, but the acidity is usually high. 
