STUDIES ON FRUIT 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. 
