ANNUAL REPORT, 1938 75 



vitamin C in the spinach could be recovered from the cook water. Freezing and 

 incidental operations caused a loss of about 45 percent of the vitamin C, and 

 canning 60 to 65 percent. Dehydration of spinach resulted in total destruction 

 of vitamin C. 



Dehydroascorbic acid was not found in either raw, frozen or canned spinach. 

 Iodine titration values for ascorbic acid averaged 19 percent higher than the 

 indophenol values. Satisfactory checks were obtained on both raw and cooked 

 spinach by the indophenol dye titration and animal bioassay methods. 



In a study made to determine the effect on vitamins B^ and B., (G) of freezing 

 and canning vegetables, work has been completed on asparagus, peas, lima beans, 

 and spinach with the following results: 



Percentage Retained — 



Raw Vegetables 



Vegetable International Units On On 



per Gram Freezing Canning 



B, B, B, B, B, B, 



Asparagus 0.66 0.48 74 95 71 78 



Peas 1.48 0.61 97 100 66 100 



Lima Beans 0.65 109 46 84 25 73 



Spinach 0.4 1.54 92 91 87 38 



Thus, generally speaking, both frozen and canned vegetables are good sources 

 of both vitamins Bj and B., . 



Extreme variations were shown in ascorbic acid content of fresh spinach, peas, 

 and other vegetables as delivered to the Boston market throughout the year. 

 Massachusetts-grown spinach varied from .14 to .47 milligrams of ascorbic acid 

 per gram and was no higher in ascorbic acid than shipped-in spinach from Texas 

 or Virginia. The same holds true for most other vegetables. The average values 

 for fresh vegetables when cooked were approximately the same as for the frozen 

 product. 



Freezing and canning processes were only slightly destructive to the carotene 

 content of vegetables. For the maximum retention of both ascorbic acid and 

 carotene in fresh or frozen fruits and vegetables, precautions must be taken to 

 avoid exposure and oxidation. 



A method for the estimation of carotene in green vegetables has been published 

 {Proc. Am. Soc. Hort. Set. 52, 728-733.) In spinach, the mean ratio of vitamin A 

 potency (in international units per gram, as determined by the rat assay) to 

 carotene content (in micrograms per gram) was 1.7. By using the above value, 

 fresh, frozen, canned, and dehydrated spinach contained, respectively, 718, 545, 

 481 and 495 international units of vitamin A per gram. Storage of canned and 

 frozen spinach for several months had no effect on its vitamin A content. 



Possible Nutritional Aspects of Arthritis. (\Vm. B. Esselen, Jr. and C. R. 

 Fellers.) In this research project, conducted under the Lang Fund, it was pre- 

 viously found that iodine, kelp, and vitamins B^, Bj (G), and D in the diets 

 of guinea pigs had no effect on the development or the pathology of scurvj'. 



This study has been continued with an investigation on the curing of scurvy 

 in guinea pigs. Guinea pigs were kept on a vitamin C-free ration until scurvy 

 had developed; then fed optimal amounts (10.0 mgm.) of vitamin C daily. In 

 addition to the vitamin C treatment some of the groups of animals were fed 

 10,000 international units of vitamin D daily, or received 10 percent of dried 

 yeast in their ration as a source of vitamins Bj and Bj (G). The results indicate 

 that relatively large amounts of vitamins Bj and B., (G), in addition to optimal 

 amoimts of vitamin C, in the diet of scorbutic guinea pigs were of value in hasten- 

 ing their recovery from scurvy. 



