STUDIES ON FRUIT JUICES. 13 
Discussion.—The color and flavor, while thus found to be injured 
but slightly by sterilization, deteriorate greatly on keeping, even 
though carbonated and kept in cold storage. Only in freezing 
storage are the color and flavor satisfactorily retained. It is, how- 
ever, possible to keep red raspberry juice by freezing storage methods. 
PINEAPPLE JUICE. 
Florida-grown red Spanish pineapples were used in all cases. 
Pressing.—High yields of juice were invariably obtained. Juice 
derived from the peels possessed rather disagreeable soapy flavors. 
Fresh pineapple juice prepared from crushed unpeeled pineapples 
was, therefore, less attractive than that from pineapples which were 
peeled before being pressed. It was found, however, that pine- 
apples which had not been peeled or previously crushed, but the 
crowns of which had been removed, might be placed on their sides 
in cloths on extra heavy racks and pressed. So prepared, the juice 
was not perceptibly injured by off flavors derived from the peel. 
Effect of heating on flavor.—Although heating the juice caused 
slight but definite changes in flavor, it did not markedly injure the 
~ ‘juice. 
Effect of storage on color and flavor.—Gradual darkening occurred 
where precautions were not taken to exclude atmospheric oxygen in 
bottling. This color change was controlled by bottling the juice in 
carbon dioxid. In addition to this, carbon dioxid imparted an agree- 
able flavor to the juice, simulating the freshness of the original fruit. 
When stored at common temperatures, the gradual development of 
a peculiar taste, designated as a stale flavor, occurred, and much of 
the rich flavor of the original juice disappeared. The characteristic 
flavor, however, was sufficiently well retained for recognition of the 
juice as pineapple. Cold storage at from 32° to 35° F. prevented 
perceptible losses in flavor during a period of 74 months. 
Storage at freezing temperatures.—During storage at freezing tem- 
peratures, — 10° C. (14° F.), the color and flavor were well retained. 
Special methods—A voluminous precipitate formed on heating 
pineapple juice. A treatment consisting of warming the juice to 
85° C. and allowing it to stand for one hour was sufficient to com- 
pletely precipitate the heat-coagulable substances. The bulk of the 
coagulum was removed by passing the cooled juice through the milk 
separator. Filtration through paper pulp was thus greatly facili- 
tated, as clogging of the filter was retarded by the removal of the 
coagulum. ; 
Discussion.—It is necessary to take special precautions in the 
preparation and storage of pineapple juice to prevent deterioration 
in distinctive color and flavor. Sterilization and the subsequent 
keeping of the juice free from contact with atmospheric oxygen result 
