Stabilization mechanism of ultrasonic treatment on diacylglycerol emulsion based on soy protein isolate and sodium alginate and its effect on diacylglycerol oxidation

BACKGROUND: Diacylglycerol (DAG) is a functional lipid, but it is easily oxidized. The present study aims to evaluate the stabilization mechanism of DAG-loaded emulsions stabilized by soy protein isolate (SPI) and sodium alginate (SA) under varying ultrasonic power levels (0, 150, 300, 450, 600 and 750 W), alongside its impact on DAG oxidation. RESULTS: Ultrasonic treatment significantly enhanced adsorbed protein content without altering the composition of adsorbed proteins or the types of fatty acids in the emulsion. Specifically, 450 W ultrasonic treatment modified the SPI structure, increased the β-sheet content from 6.29% (untreated) to 29.68% and exposed hydrophobic groups. This structural change effectively restricted the mobility of water molecules in the emulsion, thereby improving stability. Concurrently, the 450 W treatment significantly reduced the peroxide value and thiobarbituric acid reactants value in the emulsion throughout storage. After 24 days, these values had decreased by 44.4% and 37.7%, respectively, compared to the control group (0 W), indicating a marked improvement in oxidative stability. CONCLUSION: These discoveries offer a theoretical basis for the application of ultrasonic technology in the construction of high-performance SPI-SA stabilized DAG emulsion systems. © 2025 Society of Chemical Industry.