الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
The present investigation was carried out in order to study the effect of different cooking methods commonly consumed in Egypt on the vitamin C content. Several pre servation methods were also studied in view of their effect on the vitamin C content in addition to studying the effect of different storage conditions on its content. Additionally we study the effect of species variability of fruits and \ vegetables on the vitamin C content. The results of this study can be summarized as follows: 1. Vitamin C shows a great species variability and its content is differ from one variety to the other. In all varieties studied in this investigation a great variability was obtained in the vitamin C content. As an example, in green peppers, Long Red variety has a vitamin C content higher than Corn-El-Gazal and Califor nia Wonder varieties. In potato, Cara variety has higher vitamin C content, in tomatQ, Castle Rock, in strawberry, Taioga and in guava, the seedly variety has the highest vitamin C content. 2. Additionally around 15.9 and 14.2 of vitamin C content of potatoes was concentrated in the outer peel of potatoesiA Cara and Alfa respectively. 3. Processing temperature used in preparing fruits or vege tables has a direct effect on the vitamin C content. In our study we used 4 different processing conditions commonly consumed in Egypt and the following was obtained: 3.1- Frying at 197°C for 10 minutes in Cotton seed oil mixed with sunflower oil reduced the vitamin C content of green pepper by 18.0, 28.7 and 33.8 in Long Red (hot), Corn E1-Gaza1 (semi hot) and California Wonder (sweet) varie ties, respectively. Fried potato has 56.1 and 52.7 in Cara and A1fa varieties less vitamin C compared to fresh potato. Thi~ loss is due to peeling, washing and ~rying of the potatoes in oil at 197°C for 10 minutes. 3.2- Boiling in small amount of water at 118°C for 30 minutes of unpee1ed potatoes reduced the vitamin C content by 35.0 and 43.2 in Cara and A1fa varieties respectively. 3.3- Baking at 160°C for 30 minutes of unpee1ed potatoes re duced vitamin C content by 43.2 and 49.1in Cara and A1fa varieties, respectively. 3.4- Boiling of tomato for 10 minutes at 100°C to prepare I I j i tomato paste cause loss of the vitamin C content.