Singlet oxygen-related photooxidative stability and antioxidant changes of diacylglycerol-rich oil derived from mixture of olive and perilla oil.

This study investigated the oxidative stability and antioxidants changes in diacylglycerol (DAG)-rich oil under singlet oxygen. DAG-rich oil was derived from triacylglycerol (TAG) oil of extra virgin olive and perilla oil mixture by hydrolysis and re-esterification using lipases. The oxidation of oils was performed at 25 °C for 48 h under singlet oxygen produced with chlorophyll b under light, and was evaluated by headspace oxygen consumption and peroxide value (POV). The oxidation of DAG-rich oil was higher and faster in the co-presence of light and chlorophyll than in their single presence. DAG-rich oil was more oxidation-susceptible than TAG oil. There was no significant change in fatty acid and lipid subclass compositions in DAG-rich oil during the photooxidation. Tocopherols were degraded, whereas polyphenols weren't during phootooxidation of DAG-rich oil. The oxidation of DAG-rich oil was well-correlated with tocopherol contents, not with polyphenol contents, indicating that tocopherols were effective antioxidants in the singlet oxygen-related phootooxidation of DAG-rich oil. The results suggested that the oxidative stability of DAG-rich oil under singlet oxygen be improved by a precise control through retention of tocopherols. The results of this study can be applied to the utilization of diacylglycerol oils to the area of functional edible oils with good oxidative stability.