VARIATION OF VITAMIN CONTENT OF SHANGHAI FOODS AND THE INFLUENCE OF COOKINGⅠ. VITAMIN C IN VEGETABLES
- VernacularTitle:上海地区食物中维生素含量的差异和烹调的影响——Ⅰ.蔬菜中的维生素C
- Author:
Liang MAO
- Publication Type:Journal Article
- From:
Acta Nutrimenta Sinica
1956;0(02):-
- CountryChina
- Language:Chinese
-
Abstract:
From previous investigation, it appears that vitamin C content of one variety of vegetable as found in the market may vary considerably. However data on this point are few. Present study investigated the variation of vitamin C content of a number of common vegetables available in the Shanghai market and the influence of different methods of cooking. Harris & Olliver method slightly modified was used to determine the ascorbic acid and dehy-droascorbic acid. Roe, Mills, Osterling & Dainron method was also used to determine the ascorbic acid, dehydroascorbic acid and diketogulonic acid.The results were as fellows:1.Among 26 different vegetables, the vitamin C of each variety taken at different times of the year showed a variation from less than 1 to 5 times. Generally the variation was from 2 to 3 times. Spinach, green peppers, potato, small onion, aster shoots, foreign cabbage, leeks, string beans showed variation of from 3 to 5 times. Majority of the vegetable showed vitamin C content similar to those in Peking, a few showed values twice as high as those in Peking.2.Dehydroascorbic acid was present in all but 2 of the 35 kinds of vegetable tested. The majority showed less than 10% of the total vitamin C. Eight vegetables showed a presence of 10-20%, seven vegetables 21-50%, and only one vegetable over 50%. Among 32 kinds of vegetable studied, the majority showed an absence of dikitogulonic acid, only a i'ew showed a trace of the acid.3. Four different methods of cooking were used. The loss of ascorbic acid during quick frying (used small amount of oil) was 6.2-48.7%, averaging 25.2%. Dehydroascorbic acid and ascorbic acid showed a total loss of from 7.3-46.8%, averaging 23.4%.Boiling of vegetable caused a loss of ascorbic acid of 4.6-50.6%, averaging 16.2%, while the loss of the sum of ascorbic acid and dehydroascorbic acid was 4.6-40.4%, averaging 15.3%.Steaming of vegetable on the whole caused a destruction of vitamin C more than quick frying and quick boiling. The average loss was 31.9% of ascorbic acid and 23.6% of the sum of ascorbic acid and dehydroascorbic acid.Salting of vegetable for one hour caused an average loss of 24,7% of ascorbic acid and an average loss of 18.1% of the sum total of ascorbic acid and dehydroascorbic acid.Standing for one hour after steaming caused an average loss of about 73% of ascorbic acid, while standing for one hour after quick frying caused only a loss of about 13% of ascorbic acid.
