16 BULLETIN 241, U. S. DEPARTMENT OF AGRICULTURE, 
The milk separator can be used in removing oil and the bulk of the 
suspended matter. Preliminary experiments show that the addition 
of infusorial earth to the juice will make possible the preparation of 
a brilliant juice entirely free from suspended matter or sediment. 
ORANGE JUICE. 
Florida- and California-grown oranges were used. 
Pressing.—Pressing was successfully accomplished by cutting 
each orange transversely into two or more pieces, forming the cut 
fruit into ‘‘cheeses” (p. 2) in cloths and then pressing it. Extra 
heavy or double racks were required. Removing the peels before 
pressing was found inadvisable, as juices:so prepared were deficient 
in orange flavor, and cooked tastes, developed during sterilization, 
were more prominent than in juices prepared from unpeeled fruit. 
In a typical experiment with Florida oranges the yield of juice was 
52.7 per cent. 
Sterilization and keeping after sterilization —The juice underwent 
a slight but distinct change in flavor on being sterilized at 80° C. 
When afterwards kept at temperatures of from 32° to 35° F., no 
further flavor change occurred for many months. When kept at 
ordinary temperatures, however, marked flavor deterioration oc- 
curred. The flavor changes were accompanied by darkening of 
color, which, however, could be controlled by carbonating the juice 
and sterilizing it in carbon dioxid. The suggestion of excluding the 
air from contact with the surface of orange juice to control color 
change is due to R. F. Bacon, formerly of the Bureau of Chemistry. 
It has been tried with other fruit juices, and, as already described 
(p. 7), found useful in the case of lemon and pineapple juices. 
Carbonating or keeping in carbon dioxid had no effect on the reten- 
tion of the distinctive flavor of orange juice. 
Removal of sediment from orange juice.—Freshly expressed orange 
juice contained much suspended matter which detracted from the 
appearance of the sterilized juice. Experiments consisting in passing 
the juice through the rotating bowl of a milk separator showed that 
a large part of the suspended matter can be easily removed. A small 
portion of the juice carrying the orange oil passed from the separator 
through the cream screw. A certain amount of this juice, added to 
the main body of juice which has passed from the milk separator 
through the milk screw, restored the flavor of orange oil to the juice to 
the degree desired. Infusorial earth added to orange juice promotes 
filtration. 
Freezing and thawing orange juice—Upon freezing orange juice and 
allowing it to thaw, more or less complete coagulation of suspended 
matters occurred. This fact is possibly of importance in the develop- 
ment of the technique of preparing a clear orange juice of satisfactory 
flavor. 
