18 BULLETIN 241, U. S. DEPARTMENT OF AGRICULTURE. 



of other fruit juices, except in cases where the heat employed was 

 excessive. 



Retention of Distinctive Colors and Flavors. 



The extent to which color and flavor were retained on keeping the 

 juice after sterilization varied greatly in the juices from the various 

 fruits. 



In strawberry juice the brilliant red color of the freshly sterilized 

 juices in all cases faded greatly and further flavor losses occurred. 

 Sterilization and subsequent keeping in carbon dioxid were not 

 effective in securing color retention. 



Red currant juice very gradually lost in distinctive color and flavor 

 on being kept at room temperatures after sterilization and keeping 

 in carbon dioxid was not effective in securing either color or flavor 

 retention. Cold storage at from 32° to 35° F. was found to be a 

 very satisfactory means of controlling color and flavor changes. 



The distinctive colors and flavors of black currant, blackberry, 

 and black raspberry juices were satisfactorily retained during pro- 

 longed periods at common storage. The flavor of blackberries was, 

 however, distinctly less well retained than that of black currants or 

 black raspberries, though it did not undergo a perceptible change 

 during a storage period of six months. 



In the case of red raspberries the distinctive color and flavor were 

 poorly retained, even on keeping the juice in carbon dioxid in cold 

 storage at from 32° to 35° F. 



When sterilized and subsequently kept in carbon dioxid the 

 distinctive color of pineapple juice remained practically unchanged. 

 When exposed to atmospheric oxygen at juice surfaces during and 

 after sterilization, marked darkening occurred. Change in color 

 was also found to be greatly, though not wholly, retarded by keep- 

 ing the juice in cold storage at from 32° to 35° F. On keeping the 

 juice at ordinary temperatures the distinctive pineapple flavor 

 gradually lessened, though the juices remained recognizable as 

 pineapple. By keeping in cold storage at from 32° to 35° F. flavor 

 change was almost wholly prevented. 



The distinctive colors and flavors of peach and cherry juices were 

 quite well retained while kept at room temperatures. Huckleberry 

 juice, hot pressed, lost in flavor on keeping. 



Lemon juice darkened in color if sterilized and kept in the pres- 

 ence of atmospheric oxygen, though the color was satisfactorily 

 retained when the juice was sterilized and kept in carbon dioxid or 

 in vacuum. In all cases an off-flavor, designated as a "bottled 

 lime-juice" flavor, appeared in the lemon juice after it had been 

 kept for a time after sterilization, even though in cold storage at 

 from 32° to 35° F. 



