Interfacial Lipid Oxidation and Antioxidation

抄録

Lipid oxidation is not well understood in systems in which the fat is dispersed in emulsion systems. Interfacial oxidation is a “surface” reaction dependent on the rate of oxygen diffusion and its interactions with unsaturated lipids, metal initiators, radical generators and antioxidants, which are distributed in different campartments of colloidal systems. This interfacial oxidation affects a large number of foods, which exist in the form of emulsions. The classical mechanism of inhibited lipid oxidation does not predict the changes in antioxidant effectiveness between solutions and emulsion systems.
   In multiphase systems antioxidants partition between the aqueous phase, lipid phase and surfactant-enriched environment. This partition of antioxidants in different phases changes their activity in food and biological systems. In these multiphase systems antioxidant effectiveness is determined by the heterogeneity and heterophasic nature of the/system, the localization of antioxidants in different phases, the colloidal properties of the substrates, the conditions of oxidation , and the stages of oxidation, the type and physicochemical state of the lipid substrate and its degree of unsaturation, the presence and types of initiators, such as transition metals, other components, and their possible interaction. Antioxidant activity is thus strongly affected by the physical composition of the test system, and the relative activity of antioxidants of different polarity varies significantly in different multiphase systems. For these reasons there cannot be a simple and rapid method to evaluate antioxidants in complex foods and biological systems. Valid methods require the use of more than one condition of oxidation and more than one specific method to determine lipid oxidation.