6 MASS. EXPERIMENT STATION BULLETIN 338 



There are few data bearing on the effects of drying, freezing, or canning 

 processes on vitamin D. However, it is well known that the D is retained in 

 canned salmon, sardines, and similar products. Moore and Moseley (144) 

 found an appreciable amount of D in canned shrimp. The vitamin is stable 

 to heat and moderately stable to oxidation. Steenbock, Scott, and Irwin (205) 

 showed that vitamin D when added to boiling doughnut fat is rapidly destroyed. 

 However, irradiated or other vitamin D milks may be pasteurized without 

 loss of vitamin D. Kohman, Sanborn, Eddy, and Gurin (112) have recently 

 stated that the calcium in canned vegetables seems to be very readily available 

 and they believe certain canned foods contain appreciable and significant 

 amounts of vitamin D which cannot be measured by present assay methods. 

 McCay (124) has taken exception to these conclusions. There seems to be 

 no doubt as to the presence of a small amount of vitamin D in corn silage, 

 fresh grass, and hay, as reported by Hodgson and Knott (89), Rygh (179\ and 

 many others. 



In summarizing the existing data on vitamin D in fruits and vegetables, 

 it seems safe to assume that no marked losses occur in storage, freezing, or 

 canning. Oxidation is destructive. There is need for new research on vitamin 

 D in fruits and vegetables, and its relationship to mineral metabolism in 

 animals and humans. The D factor may prove to be more important than 

 is now commonly conceded. Of more than passing interest are the results 

 of Kohman, Eddy, and Gurin (109), who successfully raised five generations 

 of rats and three of guinea pigs on diets consisting only of canned foods. Such 

 results would indicate that by selection, man's dietary needs can be fully met 

 by preserved foods, and of course this means all the vitamins. 



VITAMIN E 



It was only twelve years ago that a specific vitamin essential for repro- 

 duction was definitely shown to exist. A good survey of existing knowledge 

 on this vitamin has been made by the British Medical Research Council in 

 their book "Vitamins, A Survey of Present Knowledge" (137). Wheat germ 

 oil is one of the richest sources, but there seems to be a very general distribu- 

 tion of vitamin E in leafy vegetables, cereals, meats, dairy products, and eggs. 

 Largely because of assay difficulties, only relatively few foods have been care- 

 fully studied for their content of vitamin E. The richest natural sources of 

 the vitamin are green leaves and the embryos of seeds. It is absent in the 

 endosperm of cereals. Vegetable oils contain, as a rule, small but significant 

 amounts of this vitamin. Sherman and Smith (193) quote experiments to 

 show that dried lettuce leaves, tea, and various dried seeds retained their 

 vitamin E unimpaired. Both oranges and bananas contain E in small amounts. 



Vitamin E appears to be remarkably stable to heat, hydrogenation, saponifi- 

 cation, and distillation. Under some conditions it is susceptible to oxidation, 

 particularly in fats and oils exposed to air. While E is fat-soluble, a small 

 amount of the vitamin can be extracted with water. Kohman (106) cites 

 several experiments to show that vitamin E is very stable to boiling, cooking, 

 and even autoclaving. Surely, usual canning processes would have no effect. 

 Similarly, though no studies have been reported, freezing and cold storage 

 are probably without effect. 



