Tomato peel was treated by ethanol 70% (v/v) to extract flavonoids (kaempferol, quercetin, lutolin, narginine and rutin) and phenolic acids (P-coumaric, ferulic and chlorgenic acids) were identified by paper charomatographic technique. Natural and synthetic (butylated hydroxyanisol, BHA) antioxidants exhibited strong and close antioxidative activities 85.85 and 92.60%, respectively. The tomato peel extract and BHA were added to sunflower oil at levels 100, 150 and 250 ppm to keep its quality during heating at 180 0 C for 32 hours. Moreover, the natural and synthetic antioxidants were added to cake made up by sunflower oil at the same levels. Cake was stored at room temperature for four weeks and the lipids were extracted every four days.The results showed that the addition of tomato peel extract as natural antioxidant to sunflower oil and cake delayed the lipid peroxidation during heating oil and storage of cake.
INTORDUCTIONTomatoes (Lycopersum esculentum) are widely consumed either raw or after processing and can provide significant properties of total antioxidants in the diet. This is largely in the form of carotenes and polyphenolic compounds (Clifford,1999).Moreover, tomato-processing by product, also known as tomato pomace, consisting of peel and seeds and represents around 4 % of the fruit weight. If these wastes remain unused, they not only add to the disposal problem but also aggravote environmental pollution (Valle et al.,2006).Tomatoes peel contains flavonoids mainly naringenin chalcone and the flavonol rutin , quercetin glycoside. Flavonols are very potent antioxidants and their dietary intake is correlated with a reduced risk of cardiovascular diseases ( Bovy et al., 2002).Flavonoids from a large group of polyphenolic compounds that occur naturally in plants. Based on their core structure. The aglycone, they can be grouped into different classes, such as chalcons, flovanones, dihydriflovnols, flavonols and anthocyanins. To over 4000 different flavonoids have been identified. This large diversity is attributable to single or combinatorial modifications of the aglycone, such as glycosylation, methylation and acylation. As a group, flavonoids are involved in many aspects of plant growth and development, such as pathogen resistance,