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

UNLABELLED: 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. PRACTICAL APPLICATION: 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.