Concentration-dependent structural transition and thermoreversible behavior in WPI oleogels containing glyceryl...

In this study, 2 wt% whey protein isolate (WPI)-based oleogels were constructed using glyceryl monostearate (GMS). The effects of GMS concentration on the microstructure, rheological properties, thermal behavior, crystallinity, oil-holding capacity, and structural recovery of the oleogels were systematically investigated. Increasing GMS concentration progressively transformed the structure from a loose WPI-based matrix to a denser structure with developed crystalline domains. At 3 wt% GMS, a detectable crystalline phase emerged, accompanied by the onset of thermoreversible behavior. Increasing GMS concentration to 5-7 wt% enhanced oil-holding capacity, viscoelasticity, and structural recovery. At 9 wt% GMS, the oleogel exhibited the highest viscosity and crystallinity, but its structural recovery was markedly lower than that of the intermediate-concentration systems. These results demonstrate that the functional properties of low-protein WPI oleogels depend on the concentration-dependent evolution of the crystalline phase rather than on structural reinforcement alone. The findings provide a theoretical basis for regulating the structural and thermal behavior of WPI-based oleogels through GMS concentration.