Abstract
After heating the decrease of the oxidative stability by tocopherol (Toc) degration was larger for olive and high oleic safflower oils than for soybean or corn oils. In this paper, the inhibition effect of each additive on the thermal oxidation of Toc in olive oil by heating was investigated. Olive oils containing natural α-Toc 9.1 and γ-Toc 1.9mg% were heated with ar without each additive in a glass tube for AOM test at 180°C for 10hr, and the percentage of remained Toc and the oxidative stability measured by weighing method were estimated.
The preventive effects of additives on the thermal oxidation of Toc in olive oil were in the order of gallic and thiodipropionic acids>cystine>homogentisic acid>tryptophan>phenothiazine>lecithin, but not observed for oryzanol, adenine and cytosine. Gallic and thiodipropionic acids showed the great preventive effects on the thermal oxidation of Toc in olive oil by heating at the concentration of 0.03%. Consequently, the oxidative stability of heated olive oil was considerably improved with the addi- tion of gallic and thiodipropionic acids.
