Losses of Vitamin C During the Cooking of Swiss Chard

Abstract

The leaf portion of fresh raw Swiss chard is a good source of vitamin C (the leaf minus the stem contains about 0.38 mg. per gram). The stem of fresh raw Swiss chard is a relatively poor source of vitamin C (about 0.08 mg. per gram). Cooked chard contains from 0.14 to 0.18 mg. of vitamin C per gram. The two varieties of Swiss chard studied contained about the same amount of vitamin C. About one-half of the original vitamin C passes into the cooking water by the method of cooking used. The so-called ascorbic acid oxidizing enzyme is very active in Swiss chard as indicated by the large amount of dehydro-ascorbic acid found in raw chard after extraction with acetic and metaphosphoric acid. The enzyme is inactivated during the first few minutes of cooking.