Kinetics of off flavor formation in some lipidic fractions and improvement of their keeping quality

Abstract

Rancidity of edible oils, fatty foods and drugs due to lipid oxidation is a serious problem in food and drug industries. Factors, which have contributed to this problem in recent years, are the increased emphasis on polyunsaturated dietary lipids and the fortification of certain foods and drugs with iron (1 ). Unsaturated lipids are important for the structural and functional integrity of biological membranes. For this reason, lipid oxidation can cause biological damage that may be derived from changes in the diet and our environment (2). Changes in the diet such as increases in polyunsaturated fats without adequate protection, or without an increased intake of tocopherols and other antioxidants, may cause or accelerate in vivo oxidation with potential damage to membranes and vital cell functions (3). Similarly, atmospheres contaminated with traces of ozone and nitrous oxide accelerate lipid oxidation with potential damage to stored foods and biological systems (4,5). Prostaglandin-related cyclic peroxides and other biological oxidation products such as leucotrienes and epoxy unsaturated fatty acids affect many important physiological activities including a role in the inflammatory process (6-9). There is also the universally important problem of ageing, which has been related to various forms of biological lipid oxidation (10). Finally, the toxicity of thermally oxidised oils has attracted considerable attention (11-13). Because of the unfortunate and immediately sensorically perceivable consequences of lipid oxidation in foods and drugs, it is critical that information about the oxidative stability of susceptible food and drug items be obtained before they are marketed (1).