Effect of tocopherols and phytosterol on color reversion of mct

Abstract

Tocopherols and phytosterols were added to medium chain triacylglycerol (MCT) to study their effect on color reversion of vegetable oils. Four samples with 0, 6,000, 10,000 and 14,000 mg/kg phytosterols were heated at 105°c for 12 h. No significant reduction of phytosterols and obvious color change were found in the four samples. Five samples with 0, 1,000, 2,000, 5,000, 10,000 mg/kg tocopherols were also heated at 105°c for 12 h. About 2 . 5% tocopherols were absent after heating. Reduction of total tocopherol was found linearly related to color darkening. The most significant reduction is α-tocopherol. Reduction of α-tocopherol correlated more with color darkening than that of γ-tocopherol. The conclusion is phytosterol has no effect on color reversion of oils and reduction of α-tocopherol was attributed to be the most important cause of color reversion.