Thermal properties, oxidative stability, and frying applicability of highly pure soybean-based diacylglycerol oil

Diacylglycerols are appreciated for their unique nutritional and pharmaceutical values. This study compared the thermal characteristics, oxidative stability, and frying applicability of a high-purity soybean-based diacylglycerol oil (SDO, 98.07%) and soybean oil (SO, 98.80%) that had similar fatty acid compositions. SDO showed similarity in solid fat content (SFC) at 35–40°C, whereas it showed differences in crystallization behaviors compared with SO. Specifically, SDO had crystals mainly in β form and its onset temperature of initial crystallization shifted to higher-melting temperature region. During thermal degradation, the contents of linoleic acid and linolenic acid in SDO decreased significantly lower than in SO, indicating higher oxidative stability of SDO. Potato strips and chicken drumsticks deep fried in SDO showed more desirable textures compared with those deep fried in SO. Glycidyl esters and 2(3)-monochloropropane-1,3(2)-diol esters were not detected in SDO after deep frying. Therefore, SDO serves as a potential alternative to SO for deep frying in food industry. Practical applications This study analyzed the physicochemical characteristics of highly pure soybean-based diacylglycerol oils comprehensively, and explored their thermal stability and applicability for food deep frying. The informative data and exploration would contribute to the potential utilization of soybean oil-based diacylglycerol oils in food processing.