Effects of alpha-Tocopherol, beta-Carotene and Epigallocatechin Gallate on the Oxidative Stability of Sunflower Oil

Using sunflower oil as the oil matrix, the antioxidant effects and types of interactions of three natural components, alpha-tocopherol, beta-carotene and epigallocatechin gallate (EGCG), were investigated and the kinetic model of oxidation reaction was established. The results showed that the ability of the three antioxidants to scavenge DPPH radicals was ranked as EGCG > beta-carotene > alpha-tocopherol in the concentration range of 0 similar to 100 mg/kg. 15 samples were obtained by combining two of three natural components. When the concentration ratios of beta-carotene and EGCG were 1:20 and 1:7.5, alpha-tocopherol and EGCG were 1:13.3, 1:6, and 1:2, and alpha-tocopherol and beta-carotene were 1:0.2 and 1:0.05, the type of interaction was synergistic, while the rest of the samples showed antagonistic effects. The sample with a 1:13.3 concentration of alpha-tocopherol and EGCG showed the longest induction period, the lowest oxidation rate constant, the highest activation energy, the best oxidative stability, and the longest shelf life at different temperatures. This compounded natural antioxidant was the most favorable for the stability of sunflower oil. This provides some theoretical basis for the development and application of compounded natural antioxidants in vegetable oils.