OXIDATIVE INTERACTIONS OF CHOLESTEROL WITH TRIACYLGLYCEROLS

Triacylglycerols (TGs) accelerated the decomposition of cholesterol at 130-degrees-C. Addition of stearic and linoleic acids also accelerated cholesterol decomposition and produced characteristic cholesterol oxide profiles, qualitatively different from those produced in the presence of TGs. Milk fat accelerated cholesterol decomposition at 130-degrees-C and produced a cholesterol oxide pattern similar to that arising from the addition of pure TG. Not only did TGs affect cholesterol oxidation, but cholesterol influenced the decomposition of TGs. Addition of cholesterol accelerated the destruction of TGs at the beginning of heating while protecting them later. A similar pattern, i.e., acceleration followed by protection, could also be seen when triacylglycerols were heated in the presence of other triacylglycerols. The results of this work demonstrate that the stability of lipid components in complex mixtures is influenced by interactions among these components and/or their decomposition products. Such interactions do not merely shift, i.e., accelerate or delay, the oxidation rate, they may also modify the shape of the oxidation curve itself.