AGEICULTUEAL CHEMISTRY AGEOTECHNY. 317 



in pressing pineapples, although the method of pressing the fruit without previ- 

 ous cutting is probably superior. It was found advisable to pass all of the 

 other kinds of fruit pressed without heating through an apple grater to facilitate 

 the outflow of the juice. 



"Heating before pressing in the case of black raspberi-y, blackberry, red cur- 

 rant, black currant, and huckleberry juices resulted in larger yields of juice 

 and the development of more color and a more distinctive flavor than were ob- 

 tained from cold pressing. Strawberries, red raspberries, cherries, peaches, 

 pineapples, lemons, and oranges were cold pressed. 



" Heating the juices sufficiently to sterilize them did not affect injuriously the 

 color of any of the fruit juices, though pineapple, lemon, and orange juices 

 usually darkened somewhat if heated in the presence of dissolved oxygen or if 

 exposed to atmospheric oxygen during the heat treatment. 



" The distinctive flavor of the fresh fruit was greatly injured and the familiar 

 cooked-strawberry taste appeared when strawberry juice was sterilized by heat. 

 The fresh fruit flavor of orange juice was also distinctly injured when the juice 

 was heated. Although all lost in the quality of freshness, heating did not 

 seriously affect the flavor of other fruit juices, except in cases where the heat 

 employed was excessive. 



" 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 subse- 

 quent 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 temperature 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 con- 

 trolling color and flavor changes. 



" The distinctive colors and flavors of black currant, blackberry, and black 

 raspberry juices were satisfactorily retained during prolonged periods at com- 

 mon 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 

 retainetl, even on keeping the juice in carbon dioxid in cold storage at from 

 32 to 35°. 



" When sterilized and subsequently kept in carbon dioxid the distinctive color 

 of pineapple juice remained pi'actically unchanged. When exposed to atmos- 

 pheric oxygen at juice surfaces during and after sterilization marked darken- 

 ing occurred. Change in color was also found to be greatly, though not wholly, 

 retarded. by keeping the juice in cold storage at from 32 to 35°. 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 presence 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 



