Investigate the changes in fatty acid and antioxidant properties of Kiwifruit (Actinidia deliciosa) peel extract on stability of sunflower oil in thermal conditions

In this study the antioxidant effects of kiwifruit peel extract (800 ppm) and synthetic antioxidant TBHQ (100ppm) on oxidation stability and fatty acids composition of sunflower oil were studied. First the kiwifruit peel extract was extracted. Then phenolic and tocopherolic compounds in extract were measured. Kiwifruit peel extract and TBHQ were added to oil in 800 and 100 ppm respectively and oil were heated in constant temperature of 180 ° C for 24 hours. Thermal oxidation factors such as acidy index, peroxide index, iodine index, conjugate index, carbonyl index, color index, oxidative stability, polar compounds, calculated oxidative stability of oil and fatty acid composition of oil were evaluated at intervals of 4 hours (0, 4, 8, 12, 16, 20 and 24). The results showed that change in fatty acids composition in oil containing kiwifruit peel extract was partly low, while samples containing TBHQ has more change in fatty acid profile at 180 ° C. Stability of oil containing TBHQ in aspect of fatty acid change (based on COX value) was higher than oil containing kiwifruit peel extract. The results also showed that kiwifruit peel extract due to the presence of phenolic compounds created higher oil oxidative stability than oil containing TBHQ. The results of this study introduced kiwifruit peel extract as good source of natural antioxidant, which can prevent the oxidation of oils and reduce undesirable effects of synthetic antioxidant on human health.