Antioxidant effect of hawk tea extracts on camellia oil oxidation during microwave heating

Hawk tea and camellia oil widely consumed in China. In this work, the addition of 3 hawk tea extracts, namely hawk bud tea extract (HBE), hawk primary leaf tea extract and hawk mature leaf tea extract (HME), to camellia oil was evaluated as potential antioxidants against oxidation under microwave heating. Quality parameters (acid value, peroxide value, K-270 and K-232), fatty acid composition, total phenols and antioxidant activity were investigated during different microwave heating exposure time (0, 3, 6, and 10 min). Microwave heating significantly increased the peroxide value, K-270 and K-232 of camellia oil as a result of oxidation. The addition of hawk tea extracts increased the availability of total phenol content in the samples, and counteracted the rise of quality parameter values, particularly during camellia oil microwave exposure beyond 6 min. In addition, HBE and HME could effectively protect camellia oil against polyunsaturated fatty acids loss, while HPM exhibited a reverse behavior. The correlation analysis between quality parameters, antioxidant activity and total phenols content shown that polyphenols were the important constituents to contribute the resistance of camellia oil oxidation.