STUDIES ON FRUIT JUICES. i 
juices in carboys, therefore, requires further study. It is not 
improbable that a method of sealing in which no air space remains 
in the carboy, or in which no oxygen is present in the gases above 
the juice surface, would result in the complete arrest of the develop- 
ment of molds. 
SPECIAL METHODS OF PREPARATION. 
As has been stated, the methods of handling just described can be 
successfully applied to but a limited number of those juices tried, 
namely, black raspberry, blackberry, black currant, sour cherry, and 
peach. In the case of strawberry, apple, and other juices which are 
greatly injured in distinctive flavor by being heated, it is possible to 
retain the flavor satisfactorily by keeping the juice in freezing storage 
at a temperature of 14° F. Although certain juices, as pineapple and 
orange, are not greatly injured in flavor by sterilization, they change 
in flavor and color upon being kept at ordinary temperatures after 
sterilization. Keeping such juices in cold storage at from 32° to 36° 
F. causes satisfactory retention of the color and flavor. Another 
cold-storage method of general application to fruit juices, and one 
particularly valuable for fruit juices the distinctive characters of 
which are injured by heat, is the method of concentrating by freezing. 
Juices of oranges, lemons, and pineapples darken greatly in color if 
sterilized and subsequently kept in contact with atmospheric oxygen. 
Satisfactory color retention can here be had by sterilizing and keep- 
ing the juices free from atmospheric oxygen, which is most conven- 
iently effected by carbonating slightly and sterilizing them in carbon 
dioxid. 
APPLICATION OF COLD STORAGE TO FRUIT JUICES. 
STORAGE OF Raw JUICES AT 32° to 35° F. 
Apple juice, cooled quickly after pressing to 32° F., and stored at 
this temperature, will keep for from 6 weeks to 3 months before it 
ferments sufficiently to be considered hard or sour.t' Unpublished 
experiments on the keeping of raw orange juice at from 32° to 35° F. 
show that its flavor deteriorates quite rapidly. An unfavorable 
feature of storage of raw fruit juices at from 32° to 35° F. is the 
development of molds at juice surfaces. It is not improbable that 
simple measures for the suppression of the mold growths could be 
successfully used, as, for example, keeping the containers entirely 
filled, or keeping the juice surfaces well blanketed with a layer of 
carbon dioxid, or possibly using ultraviolet light. It seems probable, 
however, that cold storage of freshly expressed juices at from 32° to 
35° F. is of but limited application, as the activities of microorgan- 
isms are not sufficiently held in check. 
-1U.S. Dept. Agri., Bureau of Chemistry Cir. 48. 
