Vitamin C content and juice quality of exposed and shaded citrus fruits.

That the vitamin C (ascorbic acid) con tent of a fruit is dependent upon the in tensity of incident light was suggested by findings of Zilva and his associates (10) reported in 1935. These investigators found that the red peel of Bramley's Seedling apples contained twice as much vitamin C as the green peel. Although they did not mention light as a factor in the production of this difference in vitamin content, it is well known that the red side of an apple is normally the one that has been exposed on the tree to direct sunlight. A review of the literature in 1936 failed to show that a comparison as to vitamin C content had been made between citrus fruits from shaded and exposed parts of the tree. It had long been common knowledge, of course, that shaded fruit degreens later than exposed fruit and sometimes never completely degreens and that its juice quali ty as judged by the taste test is not gen erally so high. In 1936 an investigation was begun pri marily to determine whether insolation in fluences the vitamin C content of Floridagrown citrus fruits; total soluble solids and total acid also were measured. The results of this study, terminated in 1943, are re ported herein.