Abstract: To elucidate the mechanism of the synergistic effect of Pickering stabilization with lipid droplets and glycyrrhizic acid (GA) on enhancing the stability of emulsion foams, this study systematically analyzed the sensory attributes, plasticity, stability, overrun, rheological properties, and microstructure of emulsion foams, and the effects of different oil phases, including soybean oil (SO) and its mixture with coconut oil (SO/CO) at a 1:1 ratio (V/V), and GA addition on the stability of emulsion foam systems was investigated. The results demonstrated that GA addition significantly improved whipping capacity and foam texture, and the optimal addition level was 1.5%. Compared with SO, emulsion foams formed by SO/CO exhibited superior whipping capacity, better shape retention, minimal bubble collapse, and smoother surfaces. Rheological measurements and confocal laser scanning microscopy (CLSM) further revealed that both oil-phase composition and GA concentration influenced the viscoelasticity and microstructure of emulsion foams. Compared with SO emulsion foams, SO/CO + GA emulsion foams showed higher apparent viscosity, storage modulus (G’), and loss modulus (G”), indicating better anti-disturbance ability and mechanical strength. Furthermore, these foams exhibited higher bubble density and more regular bubble shapes, with a more compact interfacial network formed by lipid particles. This enhancement was mainly attributed to the higher melting point of CO, whose solidification promoted the formation of lipid droplets with a more pronounced Pickering stabilization effect. These droplets interacted with GA in the continuous phase to form a network, thereby stabilizing emulsion foams. Overall, this study elucidates the stabilization mechanism of oil-in-water (O/W) Pickering emulsion foams in collaboration with GA, providing an important theoretical basis for developing stable, sensory-driven plant-based emulsion foam products.

Key words: emulsion foams; lipid droplets; Pickering stabilization; glycyrrhizic acid; stabilization mechanism