Vegetables as Food

Abstract

THE low mechanical efficiency with which a steam engine converts heat into energy is perennially shocking to each generation of schoolboys, but the wastefulness of the steam engine is nothing compared with the waste of vitamin C which takes place between the time a green vegetable is harvested and its final disappearance from the diner's fork. A cabbage bought at the market may perhaps be expected to contain 60 per cent of its original vitamin C content, the housewife probably throws away no more than 20 per cent of the remainder in preparing the vegetable for the pot, leaving 40 per cent of the original vitamin. During boiling, however, although a negligible proportion is destroyed by the heat, about 65 per cent is extracted by the cooking water and usually thrown away. Thus 17 per cent of the vitamin C with which the cabbage left the field is all that remains when it reaches the table, and if the dish is kept hot before being served even this small residue quickly dwindles to extinction. In 1940, one and a third million tons of green vegetables were produced in Great Britain. From this crop roughly 650,000 kilograms of ascorbic acid, or almost exactly the amount needed to satisfy the physiological requirements of the entire population for a year, was lost.