The distribution of vitamin C in foods sold on the open market

Abstract

Values for the ascorbic acid content of a number of foods sold in diverse markets were determined by titration against 2: 6 dichlorophenolindophenol in acid solution. The results showed that the least expensive material was not necessarily the poorest source of vitamin C and might be more valuable than expensive foods. Samples of cabbage from the cheap market contained 329% as much vitamin C as samples from expensive sources. These results on comparison with figures recorded for fresh garden produce showed that market foods have lost some of their vitamin C content on exposure for sale, but still contain satisfactory amounts of ascorbic acid when purchased.Results from different samples of fruits and vegetables showed wide variation. No data relating to storage before purchase were available, so limiting figures were used for each food. Mean values were calculated for purposes of comparative tabulation.The effect of household storage after purchase was noted for foods from inexpensive and fashionable markets. The values obtained showed that the loss of ascorbic acid in foods stored in the home after a period of exposure for sale, though marked, was not as serious as has previously been indicated.An irregular fall in the ascorbic acid content of some of the material examined was noted and investigated. Wide variations in the amount of ascorbic acid present in different parts of individual fruits and vegetables were observed. In view of experimental results it is recommended that foods be purchased and prepared for consumption immediately before use.Canned foods from diverse markets were examined to determine their ascorbic acid content, and it was shown that the vitamin is distributed throughout solid and liquid. Although a percentage of vitamin is destroyed on heating, those fruits and vegetables initially high in ascorbic acid retained sufficient vitamin to afford a better, and frequently cheaper, source of vitamin than unheated samples with a low ascorbic acid content. Considerable quantities of vitamin C are lost when the liquid from canned vegetables is discarded. When the syrup from cans is used as well as the fruit the vitamin available to the consumer is frequently greater than the amount yielded by the same weight of raw fruit from market sources.Raw and canned plant tissues from cheap and expensive sources were compared for their antiscorbutic value in the human diet, and for the cost of the daily requirement at ruling market prices. It was found that a day's ration of ascorbic acid could be purchased at a cost as low as a farthing to as high as a pound.