12 BULLETIN 241, U. S. DEPARTMENT OF AGRICULTURE. 
BLACK RASPBERRY JUICE, 
Locally-grown berries of the Doolittle and Kansas varieties were 
used. 
Pressing.—Upon being pressed without previous heating, yields of 
from 61.8 to 75 per cent of juice were obtained. Yields as high as 
76.18 per cent were secured by hot pressing. Pressure must be applied 
very gradually for satisfactory yields. 
Sterilization.—The juices were not injured sbbdawante in flavor or 
in color by sterilization. 
Keeping after sterilization.—Juices prepared by either hot or cold 
pressing retained their color and flavor, which were practically 
unchanged for prolonged periods at common temperatures. Special 
measures, such as keeping at low temperatures or sterilizing in carbon 
dioxid, are therefore not necessary. 
Concentration by freezing—Upon concentrating black raspberry 
juice by freezing, a peculiar coagulum formed, consisting apparently 
of flocculated coloring matter. Concentrating by freezing as applied 
to black raspberries did not appear to be of particular value, in view 
of the excellent color and flavor retention of the juice when sterilized 
and kept at room temperature. 
Discussion.—Juices can thus easily be prepared from black rasp- 
berries by crushing and then pressing them with or without previous 
heating. The characteristic color and flavor of black raspberry juice 
are excellently well retained upon sterilizing it and keeping it after 
sterilization at ordinary temperatures for prolonged intervals, even 
as long as several years. The sterilized juice is rather acid, requiring 
the addition of sugar to make it palatable. 
RED RASPBERRY JUICE. 
Locally-grown ence of the Miller, Brandywine, and Cuthbert 
varieties were used. 
Pressing.—High yields of juice, ranging from 71.9 to 82.3 per cent, 
were easily obtained by crushing and pressing the berries. It was 
necessary to press slowly and to use double press cloths. 
Sterilization.—Although red raspberry juices underwent a distinct 
change in flavor on heating, the palatability of the juice was not 
greatly injured. 
Keeping after sterilization.—The color faded and disappeared and 
the flavor changed greatly, even during storage periods of 6 months. 
Bottling the juice in carbon dioxid and keeping it in cold storage at 
from 32° to 35° F. after sterilization had no apparent effect in retard- 
ing these changes in color and flavor. 
Keeping raw juice vn freezing storage-—The color and flavor were 
excellently well retained. 
Concentration by freezing.—The color and flavor were well retained. 
Highly colored, richly flavored, very acid juices were obtained. 
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