Effect of UV and Temperature on Degradation of Tocored

Objective
γ-Tocopherol-5,6-quinone (tocored) is of importance among the γ-T derivatives. It has long been reckoned as the culprit of color reversion. In this part, we want to know the effect of heat and UV light on the degradation of tocored, which may be further contribute to address the color reversion problem.

Methods Used
High-purity tocored in free form was put into the Rancimat machine with temperatures set at 50, 100, and 150 ºC. Two kind of UV lights (365 and 254 nm) were used to investigate the degradation of tocored (two levels) in hexane and methanol. As for the content of tocored, HPLC equipped with DAD was applied.

Results
Tocored was more sustentive to the higher temperatures, with the degradation rate constant increased with temperature following the exponential function (y=0.075e^1.7733x, R²=0.9654). As for the effect of UV, higher level of tocored were susceptive to degradation at the same UV light. What’s more, the degradation rate of tocored in methanol was faster than that in hexane.

Conclusions
These results are critically needed to understand the effects of temperature and UV light on degradation of tocored during extraction, refining, and storage processes of edible oils. Further works are warranted to study these factors in the oil food systems.