Interfacial competitive adsorption of different amphipathicity emulsifiers and milk protein affect fat crystallization, physical properties, and morphology of frozen aerated emulsion

This study investigated interfacial competitive adsorption of different emulsifiers, including lipophilic [sucrose stearate 370 (S370); mono- and di-acylglycerols (MDG)] and hydrophilic [sucrose stearate 1670 (S1670) and Tween 20 (TW20)] emulsifiers with milk proteins and its influence on fat coalescence behavior in frozen aerated emulsions (10% w/w fat). Lipophilic emulsifiers accelerated fat crystallization, promoting interface heterogeneous nucleation and partial coalescence of fat droplets. In contrast, hydrophilic emulsifiers favored large fat crystal formation with a reduced rate and capacity of fat crystal protrusion. The combination of surfactants (0.5% w/w) with milk proteins (5% w/w) produced concerted effects on the stability of emulsions. The lipophilic surfactant-protein mixture also enabled strong aeration activity (overrun) and a short melting starting time. Moreover, a remarkable array of bee wax-like network was observed in such lipophilic emulsifier-stabilized frozen whipped emulsions with a similar effect seen between S370 and MDG. However, for whipped emulsions produced with hydrophilic emulsifiers, especially with TW20, fewer and irregularly-shaped air bubbles were notable, contrary to the round, slightly arching shape with glossy surface in frozen whipped emulsions with lipophilic emulsifiers. Overall, lipophilic emulsifiers were superior to hydrophilic emulsifiers in producing the well-textured frozen aerated emulsions.