Antioxidant efficacy of rosemary ethanol extract in palm oil during frying and accelerated storage

Abstract

The rosemary extract is a new natural antioxidant. In this study, the stability of palm oil with rosemary extract during frying and accelerated storage was studied. The antioxidant of palm oil with different concentrations of rosemary ethanol extract were evaluated at 180°C and 65°C. The effect of rosemary ethanol extract was also compared with the one of synthetic antioxidants. Results showed that the optimum addition of rosemary ethanol extract in palm oil during frying and accelerated storage were 0.12g/kg and 0.7g/kg. Under such conditions, a significant antioxidant effect was observed. Rosemary ethanol extract can effectively reduce the peroxide value, P-anisidine value, free fatty acid value and absorbances at 232 and 268nm, especially in the long-time frying process. It can also reduce the production of saturated fatty acids after 25h of frying and 24d of accelerated storage. Under frying condition, the oil with rosemary ethanol extract showed an enhanced stability compared to the oil with synthetic antioxidants. Under accelerated storage condition, rosemary ethanol extract could prevent the palm oil from oxidation the same as the synthetic antioxidants, but it is safer than synthetic antioxidants.