STUDIES ON FRUIT JUICES. 17 
Concentration by freezing—Concentration to a sirup was easily 
accomplished. 
Discussion.—The studies on orange juice have not led to results on 
which a method for its preparation may be based, as no way to 
successfully retain fresh orange juice flavor has been found. Steriliz- 
ing the juice injures the flavor, which continues to deteriorate gradually 
when the juice is kept at ordinary temperatures. In cold storage, 
however, the flavor is well retained. Certain features of the tech- 
nology of preparing orange juice have been mastered. Thus, the 
milk separator may be successfully employed in removing excessive 
amounts of oil as well as suspended matters from freshly expressed 
juice. Carbonating and sterilizing the juice in carbon dioxid, as 
well as cold storage at from 32° to 35° F., permit of satisfactory 
color retention. Concentration by freezing to a sirup is of promise, 
but this subject, as well as the use of infusorial earth in filtering, 
remains to be further worked out experimentally. 
SUMMARY. 
PRESSING. 
Satisfactory yields of juice were easily obtained from all of the 
fruits studied. Lemon and orange juices were best expressed by 
cutting each fruit into several pieces and then pressing, a method 
which could be successfully used in pressing pineapples, although 
the method of pressing the fruit without previous 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 raspberry, blackberry, 
red currant, black currant, and huckleberry juices resulted in larger 
yields of juice and the development of more color and a more dis- 
tinctive flavor than were obtained from cold pressing. Strawberries, 
red raspberries, cherries, peaches, pineapples, lemons, and oranges 
were cold pressed. 
Errect oF HEATING ON DISTINCTIVE COLORS AND FLAVORS. 
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 
