Oxidative Stability of Edible Oils as Affected by Their Fatty Acid Composition and Minor Constituents

摘要

Edible oils are composed of triacylyglycerols and minor constituents. The nutritional quality and stability of the oils is affected primarily by the chemical nature of the fatty acids involved, as reflected in their degree and type of unsaturation. However, minor components present in the oils also exert a major influence on their stability characteristics. The minor constituents of the oils include phospholipids, tocols, ubiquinones and other phenolics, phytosterols, carotenoids, chlorophylls, hydrocarbons, waxes and wax esters. During processing, the content of minor constituents is generally reduced by 35-95%. Thus, the Rancimat induction period of red palm oil was reduced by over 15 h at 100℃ upon removal of its minor components, mainly tocols and carotenoids. Stability of other oils was also affected by the chemical nature of their minor constituents to different degrees. Under photooxidative conditions, the positive effects of minor constituents may be overwhelmed by the photosensitizing effect of chlorophylls, if present. Thus, proper storage and packaging conditions are deemed important for quality preservation and oxidative stability of edible oils.