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 degrees 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.