Surfactant-amplified interfacial migration difference during emulsification enables efficient DAG enrichment

Diacylglycerol (DAG) has broad application potential in food, pharmaceuticals, and cosmetics, yet its mild separation from triacylglycerol (TAG) remains challenging due to their highly similar molecular structures. Herein, we propose a phase-separation-driven emulsion strategy for DAG enrichment. With Span 20 as surfactant, DAG content in the upper phase increased by 26%. DAG enrichment also occurred in the absence of surfactant, indicating that intrinsic structural differences drive partitioning, which added surfactants can synergistically amplify. Interfacial tension measurements, ATR-FTIR and molecular dynamics simulations revealed that DAG preferentially adsorbs at the oil-water interface and forms an organized interfacial layer, which promotes its selective accumulation in the upper emulsion phase. This strategy was successfully applied to DAG enrichment from corn, soybean, peanut and rapeseed oils. Overall, this study transforms emulsion phase separation into a controllable enrichment strategy, providing a green platform for separating structurally similar compounds.