Comparative Study on the Vitamin C Content of Fresh and Cooked Vegetables at Mealtime

The Main sources of vitamin C (VC) for humans are vegetables and fruits. However, ascorbic acid (AsA) in food is easily destroyed during the cooking process and storage. Therefore, VC obtained at mealtime is mainly associated with the VC content of fresh vegetables, and to the cooking method or storage period of the food. In the present study, VC content of 15 fresh vegetables, 15 cooked vegetables cooked by two methods, and 8 vegetables purchased from a delicatessen were determined by HPLC. The results from the 15 cooked vegetables demonstrated that the residual percentage of VC soon after cooking was higher in fried vegetables than in boiled vegetables. However the residual percentage of AsA in cooked vegetables after 24 hours of cold storage was higher in boiled vegetables than in fried vegetables: in the latter case, the residual percentage of AsA was 26.3% as compared to uncooked vegetables. The comparison of 8 cooked vegetables with those purchased from a delicatessen revealed that the residual VC and AsA content in delicatessen vegetables was about 1/2 and 1/4, respectively, of that of cooked vegetables soon after cooking.