Effects of acyl migration of sn-1,3 diacylglycerol on the crystallization behaviors and physical property stabilities of binary fat systems

Diacylglycerol (DAG), a functional lipid with two isomers, exhibits distinct physical properties that affect oil systems. This study investigated the crystallization behaviors and physical property stabilities in binary systems composed of sn-1,3 DAG and its migration equilibrium product (ME-DAG, with an sn-1,3 DAG:sn-1,2 DAG ratio of 65:35) at mass ratios of 20 %, 50 %, and 80 % with palm kernel oil (PKO). The results revealed that the sn-1,3 DAG/PKO systems exhibited faster crystallization rates and more pronounced eutectic effects than the ME-DAG/PKO systems. In addition, sn-1,3 DAG inhibited the polymorphic transformation (α → β' → β) in the DAG/PKO binary systems. Higher DAG concentrations enhanced the crystallization and nucleation rates. Furthermore, sn-1,3 DAG at 50 % and 80 % notably reduced post-hardening and moderated the slope of the solid fat content curve. Microscopic analysis revealed the presence of Maltese cross crystals and disordered acicular crystals in the DAG/PKO binary systems. These findings underscore the critical role of DAG acyl migration in compatibility, crystallization kinetics, polymorphism, and texture, offering insights for developing functional plastic lipids with tailored properties.