THE ASCORBIC ACID CONTENT OF LAHSA(TIBET) VEGETABLES, WITH OBSERVATION ON THE EFFECT OF COOKING METHODS / 营养学报

ABSTRACT

Determinations of the reduced aseorbic acid content of fifty different kinds of vegetables and fruits obtained in Lahsa, Tibet were carried out from May 17 to June 80 arid Oct. 22 to Nov. 7, 1952 with the indophenol titration method. Analyses were also made on the cooked vegetables prepared by quick frying for 3 minutes, quick frying and stewing for 13 minutes and boiling for 10 minutes in aluminum, iron and brass utensils.Most of the results obtained agree with those from 7 other places, namely Chungking, Chengtu, Kweiyang, Gantze, Peking, Shanghai and Nanking. However, a considerable variation was noted among the same varieties of vegetables in the 8 different localities.Among 15 kinds of edible herbs analysed, 12 gave a considerable high value of ascorbic acid. The laminae leaf contained more ascorbic acid than the tuber. Therefore, such edible herbs and the leaves of tubers should be made use of as a source of vitamin C for the inhabitants in high altitudes.The loss of ascorbic acid content of vegetables varied with the method of cooking and the type of cooking utensils. During quick frying and quick frying and stewing, there was a loss of 5.0—41.3％ and 4.4—28.6％ respectively. When vegetables were boiled in brass pan, the destruction was several times higher than when boiled in iron and aluminum pan. It is suggested that the brass pan customarily used by the Tibetans be replaced by iron and aluminum one.