Improvement of Chlorophyll-photosensitized Oxidation of Fish Oil-enriched Emulsion by Sesame Oil Addition and Antioxidant Content Changes

摘要

This study was performed to evaluate the effects of sesame oil addition to a tuna oil-enriched emulsion during chlorophyll-photosensitized oxidation. The emulsion principally consisted of tocopherol-stripped canola and tuna oil with or without sesameoil, acetic acid, phospholipids, and xanthan gum. Chlorophyll b was added to promote the production of singlet oxygen upon exposure to light. The oxidation of oil in the emulsion was evaluated by determining the peroxide value (POV) and conjugated dienoic acid (CDA) contents. Concentrations of minor compounds in the emulsion were monitored. Increasing POV and CDA contents in the emulsion were paralleled with decreased docosahexaenoic acid during oxidation, and oxidation was inhibited by the addition ofsesame oil. Chlorophyll, polyphenols, tocopherol, and phospholipids were degraded during oxidation of the emulsion; however, their degradation was slowed down by the addition of sesame oil. Lignans in the emulsions containing added sesame oil were barelychanged, suggesting that they quenched singlet oxygen physically. Polyphenols were the most effective in improving the stability of tuna oil-enriched emulsions during chlorophyll-photosensitized oxidation.