VITAMIN C 185 



with sulfite appeared to be satisfactory at low temperatures, uncertain 

 at room temperature, and unsatisfactory at 37° C. Preservation with 

 the rind oil was satisfactory and reliable at about 0° C. and room tem- 

 perature, but unsatisfactory at 37° C. Experiments on the preservation 

 of oranges and lemons in cold storage were not particularly satisfactory 

 on account of the fact that the fruit did not keep well in these par- 

 ticular cases for any length of time, but the results indicated that the 

 antiscorbutic property was not seriously diminished so long as the fruit 

 remained edible. 



This investigation was extended by Delf (1925) who determined 

 the antiscorbutic properties of the whole fruits and fruit juices after 

 storage for five years. The whole fruits (oranges and lemons), as in 

 the earlier study, retained their antiscorbutic value when kept in cold 

 storage as long as the material remained in good condition. Orange 

 and lemon juices stored in a frozen condition for five years retained 

 about half of their original antiscorbutic value. Oranges canned by 

 heating gradually to 100° C. and holding at this temperature for five 

 minutes, the whole process occupying from twenty to thirty minutes, 

 showed no loss of antiscorbutic property when first canned and only a 

 sHght decrease in activity after four years. Lemon juice preserved with 

 potassium bisulfite retained its flavor but lost about five-sixths of its 

 antiscorbutic value after storage for four and one-half years at room 

 temperature. Orange and lemon juices preserved in rind oil retained 

 their activity after from one to three years. 



The possibility of utilizing surplus and cull citrus fruits for the 

 manufacture of vitamin C concentrates led to an investigation by Goss 

 (1925) at the California Agricultural Experiment Station of the anti- 

 scorbutic properties of various commercial orange juice concentrates. 

 The products tested included concentrated whole juice, prepared from 

 ripe navel oranges by processing for about four hours under high 

 vacuum at a temperature between 40° and 45° C. (104° to 113° F.) ; 

 clarified orange sirup prepared from whole fruit by heating for thirty 

 minutes at 185° F., filtering slowly through Filter-eel, allowing it to 

 stand overnight, adding a small amount of sugar and concentrating in 

 glass enamel vacuum pans for about seven hours under a vacuum of 

 28 inches of mercury; desiccated orange juice, prepared by a spray 

 drying process with the addition of a little cane sugar; and dried ground 

 whole orange, a product prepared from sound cull oranges by grind- 

 ing the fruit, allowing it to stand overnight and then drying in a 

 dehydrator for about eight hours at a temperature of from 155° to 

 175° F. A concentrated lemon juice, prepared similarly to the orange 



