الفهرس 
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Abstract
In this study, 13 samples of fruit and vegetable by-products were investigated ”orange, mandarin peels and seeds, pomegranate peels, mango peels and kernels, guava seeds, carrot, potato, green pea, onion peels and okra by-products”. Carbohydrates were abundant component in the peel, and considerable amounts of crude protein, fat, fiber and ash. Total phenolic components were the highest concentration in both fresh and dried samples; compared with ascorbic acid, carotenoids, flavonoids and tannins. Pomegranate peels, mango peels and kernels and had the highest content of total phenols (8.88, 7.21 and 8.99 mg/g, respectively) in fresh samples and (37.66, 27.62 and 24.75 mg/g, respectively) in dried samples. The methanolic extracts of samples exhibited considerable degrees of activities towards scavenging of DPPH and ABTS free radical, good reduction power and inhibiting bleaching of β-carotene in a β-carotene/linoleic acid system. Mango kernels, pomegranate and mango peels extracts exhibited the highest degree of antioxidant activity compared with standard antioxidants (Ascorbic acid, B.H.T and Torlox). Practically; Adding mango kernels, pomegranate and mango peel extracts at different concentrations (100, 200, 300 and 400 ppm) to oil, led to enhancing and increasing of the oxidative stability of oil during accelerated storage conditions at 63°C for 16 days (Schaalʼs oven test) as well as extend the shelf life of oil, by increasing the induction periods and protection factors of oil samples, mango peels extract introducing the maximum degree of oil stability, and had the highest value of induction period (12.48 hr) at conc 400 ppm compared with induction periods of control, control + BHT and TBHQ samples were (5.20, 9.42 and 7.04 hr, respectively). And by controlling in growing rate of peroxide value (PV), mango kernel extract at conc 400 reduced this value to 18.11 meq/kg at the end of storage period compared by control, control + BHT and TBHQ samples were (47.60, 25.44 and 30.31 meq/kg, respectively). As well as; p-anisidine value (P-AV), thiobarbituric acid reactive substances values (TBARS), Totox values, conjugated diene (CD), and conjugated trienes (CT) values were decreased by increasing of the concentration of extract.