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 io 

 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. 



