High-Purity Tocored Improves the Stability of Stripped Corn Oil Under Accelerated Conditions

gamma-Tocopherol-5,6-quinone (tocored) is of importance among the gamma-tocopherol (gamma-T) oxidant products and found in corn germ oil. Investigation on tocored is impeded in part by the difficulty to access high purity tocored. In this present study, high-purity tocored is successfully prepared, and its antioxidant activity, together with gamma-T and TBHQ (positive control) in increasing concentrations in stripped corn germ oil is evaluated by Rancimat and Schaal oven tests. The stabilization factor in the Rancimat tests increases significantly (p < 0.05) along with an increase in the levels of antioxidants. Furthermore, tocored exhibits higher stabilization than gamma-T in the Schaal oven tests, although its efficacy gradually increases up to 100 mg kg(-1) and decreases significantly at higher levels (from 100 to 500 mg kg(-1)), drawn from the comprehensive parameter A (considering both efficiency and strength) changes (5.06-11.21). In addition, the curves illustrating the residual contents of tocored and gamma-T run in different ways when the four levels are taken into consideration, further bearing the above results. Tocored tends to be a potent natural antioxidant for edible corn germ oil preservation. Practical Application: The present work provides more clear procedures for high-purity tocored synthesis. Furthermore, tocored may be a potential natural antioxidant that is especially suitable for lipid base food substrates. The results of the present work contribute to the deeper understanding of the antioxidant activity of gamma-tocopherol. The antioxidant activity of tocored is higher than gamma-tocopherol in Schaal oven test. Tocored is a bright orange-red substance that affects the appearance of the edible oil. Meanwhile, gamma-tocopherol is well known for its valuable health benefits, and appropriate measures should be adopted to store oils (corn oil, soybean oil, and so on) rich in gamma-tocopherol to control transformation in order to keep stability optimal. To some degree, the practical applications of the present results are also related to the processing and storage of edible oils.