Utilization of Natural Antioxidants Extracted from by-products Using New Methods to Enhance the Oxidative Stability of Cooking Oils

Document Type : Original Article


WITH the concern of adverse effects of lipid oxidation on food deterioration resulting off flavor which led to lowering nutrition value. This study is chiefly concerned to improve the stability of cooking oils via the addition of different concentrations of plant extracts. New assisted extraction methods (ultrasonic and microwave) with eco-friendly solvents (water, ethyl lactate, ethanol) were used to obtained natural components having antioxidative potency from tomato and grape by-products. The changes in oil oxidation stability in individual and treated oils were determined using the oven test at 60 °C. Moreover, the established analytical methods such as peroxide value, inhibition of oil oxidation, p-anisidine value and total oxidation value were used to evaluate the stability of treated oils. In addition, radical scavenging activity by DPPH• assay was used to evaluate the antioxidant activity. From the results, it was found that the addition of extracted natural antioxidants (from tomato &grape by-products) improved the oil samples stability. The effect of adding 200, 400 and 600 ppm of tomato extracts and 600 ppm of grape extract to soybean and sunflower oils mixture was found to be superior to the synthetic antioxidant. These results suggest that tomato and grape extracts from by-products are safe and vital sources of natural antioxidants.