STUDIES ON FEUIT JUICES. 15 



before pressing lacked in distinctive flavor; that from cooked fruit 

 possessed a distinctive aroma which was not well retained on keeping. 

 It was intensely colored. Upon the whole, huckleberries are not of 

 promise as a source of juice. 



LEMON JUICE. 



California-grown lemons were used in all of the studies. 



Pressing. — The juice was prepared readily by cutting each lemon 

 transversely into two or more pieces, placing the fruit in cloths between 

 racks and pressing it. Extra heavy or double racks are required. 

 Good yields of juice, ranging from 35 to 40 per cent by weight of the 

 lemons, were obtained. 



Removal of sediment. — A large proportion of oil was removed from 

 the skins in pressing. This was removed by passing the juice 

 through a milk separator, which at the same time removed a portion 

 of the matter suspended in the juice. Finally, the juice was rendered 

 almost clear by filtering it through paper pulp. Infusorial earth can 

 be successfully used in preparing clear juices. 



Sterilization and keeping after sterilization. — The juice was sterilized 

 without marked loss in flavor by heating it to 70° C. for half an 

 hour. When kept at low temperatures it retained well a rich lemon 

 flavor for many weeks. Sooner or later, however, a peculiar flavor, 

 designated as the "bottled lime-juice" flavor, made its appearance, 

 the typical lemon flavor at the same time becoming less conspicu- 

 ous. Simultaneously, darkening in color occurred unless special 

 measures were taken to protect the lemon juice from contact with 

 the air. By bottling in carbon dioxid before sterilizing the juice, 

 satisfactory color retention was secured. Oxygen may also be 

 successfully kept from contact with the juice by sealing the containers 

 in vacuum. The exclusion of air, however, had no perceptible effect 

 on the retention of flavor. So far as tried, keeping the juice in cold 

 storage, at from 32° to 35° F., was not successful in controlling the 

 flavor change. 



Concentration of lemon juice by freezing. — Lemon juice is readily 

 concentrated by freezing. As lemon juice is easily sterilized without 

 marked injury to flavor, however, it is anticipated that the method 

 of concentrating by freezing will be of little value here. 



Discussion. — Up to the present time the department is not in a 

 position to suggest a satisfactory method for the preparation of 

 lemon juice, as none has been found for properly retaining the 

 characteristic lemon flavor during keeping at ordinary temperatures. 



Flavor is quite well retained, however, for at least several weeks. 

 Other features of the problem of preparing lemon juice have been 

 mastered. Satisfactory yields of juice are invariably obtained by 

 cutting and pressing. Color retention is assured if the juice is 

 lightly carbonated, and boiled and sterilized in carbon dioxid. 



