ANTIOXIDANT ACTIVITY AND THERMAL LOSS OF δ-TOCOPHEROL IN REFINED OILS AND FATS

In this study,the antioxidant activity,thermal loss of δ-tocopherol and its effect on the quality of soybean oil,palm oil,tea seed oil,and lard were investigated by using Rancimat method (110℃) and oven method (180℃).Results showed that δ-tocopherol could significantly prolong the oxidation induction period (IP) of tea seed oil,palm oil,and lard,and the IP value were positively related to the addition amount of δ-tocopherol (500~1 000 mg/kg),while it had no significantly influence on the IP of soybean oil.Under 110℃,the antioxidant activity of δ-tocopherol (1 000 mg/kg) was stronger than BHT (200 mg/kg),but was less potent than TBHQ (200 mg/kg) in palm oil;the antioxidant activity of δ-tocopherol (1 000 mg/kg) was significantly stonger both than BHT (200 mg/kg) and TBHQ (200 mg/kg)(P<0.05) in lard.The results of oven test indicated that the thermal loss rate of δ-tocopherol in oils increased with the heating period prolonging,and the loss rates were negatively related to the addition amout of δ-tocopherol.δ-tocopherol could effectively inhibit the increasing of the anisidine value (p-AnV) of soybean oil,tea seed oil,and lard under 180℃,but δ-tocopherol (500,and 1000 mg/kg) showed significantly promoting effect on the increasing of the p-AnV in palm oil.