Effects of Green Tea Extracts on the Oxidation Stability of Olive and Melon Seed Oils

The present study is aimed at exploring singlet oxygen quenching ability of methanolic extract of green tea in methylene-blue sensitized photo-oxidation of olive and melon seed oils. Purified and oven-dried samples of melon seed oil and Goya brand olive oil as obtained from the manufacturer were used for the study. In this research, the effects of methanolic extracts of green tea as an antioxidant on the oxidative stability of olive and melon seeds oils were studied. The oil samples were subjected to methylene blue sensitized photoxidation in 10% methanol in dichloromethane for a duration of 10 hours with and without added green tea extract. The oxidized oil samples were analyzed for the following parameters: peroxide value, iodine value and % free fatty acid value. The results of the study suggest that green tea extract exhibit singlet oxygen quenching ability under sensitized photoxidation, which is dose dependent for both oils under the experimental conditions.