EFFECT OF PROCESSING ON VITAMINS 13 



Effect of Drying on Vitamin C 



In prunes, peaches, and apricots, Morgan (146) showed that the use of 

 sulfur dioxide aided in retaining C to a limited extent. Gerstenberger, Smith, 

 and Hacker (69) showed that orange concentrate, dried on lactose, lost no C 

 after storage for 15 months. Morgan (146) and also Morgan, Field, and 

 Nichols (148) showed a nearly complete loss of C in drying or dehydration of 

 prunes and apricots. This laboratory found that evaporated apples, whether 

 suifured or not, retained less than 10 percent of their C. Poehino (166 j found 

 very little C in apple powder. Morgan, Field, Kimmel, and Nichols (149) 

 showed that the small amount of C present in fresh figs was entirely lost in 

 drying. Sulfur dioxide was of no value in retaining the vitamin C in white 

 figs during the drying process. 



Jancik (99) successfully dehydrated red and green peppers at low temperatures 

 so as to retain a large percentage of their original C. Yarusova (227, 228) 

 found that dried carrots and black currants lost much of their C during drying 

 and after storage of the dried product. Dried or cooked onions and leeks 

 contained practically no C, according to Matzko (136), although the fresh onion 

 juice had about 0.33 unit per gram. He found only slight loss in rutabagas held 

 in storage during the winter. Cabbage which had been suifured and dried for 

 2 to 5 months still retained approximately 160 units of vitamin C per kilogram. 



Green tea had considerable vitamin C when fresh but lost it upon drying, as 

 found by Miura and Tsujimura (143) and also Mitchell (142). 



The work previous to 1932 has been admirably summed up by the British 

 Medical Research Council in its "Vitamins: A Survey of Present Knowledge" 

 (137). "Dried vegetables have been repeatedly tried and found useless for 

 preventing human scurvy and in this respect the results of the experimental 

 work find abundant confirmation in the records of failure which have been 

 preserved. Dried fruits have a distinct, though feeble, antiscurvy value in 

 experimental trials. This result also coincides with human experience.' ' The 

 present literature review sustains this contention. 



Freezing 



Until recently there has been very little research relative to the effect of 

 freezing fruits and vegetables on their vitamin C content. Closely allied to the 

 effect of freezing is also the effect of frozen storage and defrosting, for nearly all 

 foods are stored for varying periods of time and finally defrosted before eating. 

 Fellers (52) in his summary on the effects of freezing on the nutritive and 

 public health values of foods shows that freezing has only minor adverse effects 

 on nutritive value. Some effects of freezing storage were noted in the experi- 

 ments described under "storage' ' in this bulletin. 



Cranberries were unaffected by freezing as noted by Fellers and Isham (57) 

 and by Ivanov, Bukin, Borokhovich, and Povolotzkaya (96). According to 

 Murri, Onokhova, Kudryavtzeva, and Gutzevich (158) freezing potatoes and 

 apples had no effect on their C content. The slow thawing of potatoes caused a 

 60 percent loss in the C content. Zilva, Kidd, and West (233, 335) found that 

 freezing apples was without effect on C. According to Morgan, Field, and 

 Nichols (148) fresh apricots when frozen lost all their vitamin C unless the air 



