Stability in Foods
Of all the vitamins, ascorbic acid is the most unstable under heat, oxidation, drying, and storage, which makes it one ofthe most difficult nutrients to supply in adequate amounts to troops or civil populations in wartime. In World War II the American army rations included a lemon powder fortified with ascorbic acid; if the men did not drink lemonade, as was frequently the case, their ration was deficient in vitamin C.
Alkalinity, even to a slight degree, is distinctly destructive to this vitamin; therefore, baking soda should never be added to food in cooking. Acid fruits and vegetables lose much less ascorbic acid when heated than nonacid foods. Vitamin C is extremely soluble in water and dissolves out of some vagetable during the Erst few minutes of the cooking process.
To reduce as much as possible the loss of ascorbic acid in cooking vegetables, the least possible amount of cooking water, shortest cooking time (water should be boiling when vegetable is added), and least chopping or cutting is recommended. Studies have shovm that baked, boiled, or steamed potatoes retain a large proportion of their vitamin C if cooked whole. Fresh fruits and, especially, vegetables lose vitamin C activity rapidly when stored at room temperature and somewhat less rapidly at refrigerator temperatures. Experts advise not to shell peas, cut beans, or peel vegetables until ready to cook. Quick freezing of frui ts and vegetables destroys little if any of this factor. To retain a maximum of the ascorbic acid, frozen fruits should be used promptly after tha,ving, and frozen vegetables should be plunged directly into boiling water for immediate cooking.
