Partial hydrogenation of diacylglycerol- and triacylglycerol-based oils: structure and property relationships

Partial hydrogenation is an effective approach for modulating the structural and functional properties of oils, however, the response behaviors of different glyceride molecular structures during hydrogenation remain insufficiently understood. In this study, hydrogenation models for triacylglycerol (TAG)-based and diacylglycerol (DAG)-based oils were systematically constructed under identical reaction conditions to directly compare their hydrogenation behaviors and resulting product differences. Kinetic analysis revealed that DAG-based oils exhibited higher overall hydrogenation rate constants than TAG-based oils, indicating superior hydrogenation efficiency attributed to the lower steric hindrance of DAG molecules. Compared with TAG-based oils, DAG-based oils achieved dramatically greater hardness and a broader solid fat content range under identical hydrogenation conditions, indicating superior plasticity regulation capability. Furthermore, DAG-based oils produced lower trans fatty acid levels and exhibited distinct polymorphic behavior, with coexistence of α, β', and β crystal forms. These findings demonstrate that glyceride molecular structure plays a significant role in determining hydrogenation behavior and quality formation, providing a theoretical basis for designing functional structured lipids and optimizing the quality of hydrogenated oil products through glyceride composition regulation.