Effect of Some Natural Antioxidants on Oxidative Stability of Ghee Like Product Containing High Levels of Polyunsaturated Fatty Acids

Abstract

This study was carried out to estimate the antioxidant activity and phenolic compounds of moringa and mulberry leaves extracts and evaluate the effect of addition of these natural extracts on oxidative stability of ghee like product containing high level of polyunsaturated fatty acids. Ethanolic extracts of moringa or mulberry leaves were added to ghee at concentrations of 200, 400 and 600 ppm. Also, butylated hydroxyl anisole (BHA) was added to a sample at a concentration of 200 ppm and other sample was prepared without any additives serving as control. All samples were incubated at 63 ± 1˚C/21 days to accelerate the fat autooxidation . Samples were analyzed when fresh and weekly until the end of the incubation period (21 days) for peroxide, acid values, thiobarbituric acid (TBA) test and Rancimat test. Results showed that these extracts have a high content of phenolic compounds, and gave high antioxidant activity. The ethanolic extracts at rates of 400 and 600 ppm of both extracts were more effective in preventing the development of the peroxide and acid values and TBA test in ghee like product samples compared to BHA and control ghee like product.Moringa extract was found to be more effective. Ethanolic extracts at rates of 400 and 600 ppm of two extracts showed the higher induction period as compared to BHA and control ghee like product counter parts in the rancimat. The results recommended that ethanolic extracts under study, at a concentration of 400 ppm, could be used to retard fat autooxidation in ghee like product containing increased level of polyunsaturated fatty acids.