Autoxidation of unsaturated lipids is one of the major causes of quality deterioration in food products, which results in the changes in nutritional value, organoleptic characteristics, and may even reduce the shelf-life of food products. In order to prevent or inhibit this autoxidation, synthetic and natural antioxidants are used in the food industry, respectively and have attracted considerable attention as food stabilizers. Proper measurement of lipid oxidation remains a challenging task since the process is complex and is affected by the type of lipid substrate, the oxidation agents and the environmental factors. A variety of methodologies have been developed and implemented for determining both primary and secondary oxidation products. Most common methods and classical procedures are described, including peroxide value, TBARS analysis and chromatography. This article gives brief overview of the current knowledge of lipid autoxidation, its mechanism and the major factors affecting oxidation. In addition, the methods used to determine antioxidant activity are outlined and critically discussed.

Keywords: Antioxidants, synthetic antioxidants, antioxidant activity, electron transfer, hydrogen atom transfer, oxidative stability, lipid oxidation.