Fat crystallization and physical characteristics of mung bean protein-based frozen whipped emulsions: Effect of lipophilic surfactants and quinoa hydrolysate

Abstract

Yogurt ice cream (acid frozen whipped emulsion) is a complex frozen emulsion-foam system. The study investigated the impact of three lipophilic surfactant emulsifiers [glyceryl monostearate (GMS), polyglycerol ester (PGE), and sucrose ester 970 (S970)] and quinoa hydrolysate (QH) on fat crystallization, physical properties, and morphology of frozen whipped emulsions containing fermented mung bean protein. QH serves as a sustainable and health-conscious alternative to traditional emulsifiers. pH12-shifting treatment was utilized to modulate fermentation performance of mung bean protein. Yogurt-like ice creams (10% coconut oil) were formulated using pre-whipped emulsions comprising fermented pH12-treated mung bean protein (FMP12) or native mung bean protein (NFMP), along with 0.5% (w/w) emulsifiers or QH. Pre-whipped FMP12 emulsions exhibited significantly higher emulsification stability (P < 0.05) compared to NFMP emulsions, owing to the better-balanced hydrophilic-lipophilic nature of FMP12. The individual addition of surfactants and QH promoted fat crystallization and improved the stability and viscous of FMP12 emulsion by competitively adsorbing with FMP12 at the O/W interface. Upon freezing, all three surfactants in whipped creams resulted in uniform and fine ice crystals with a moderate accumulation of oil droplets, showing a comparable effect to QH. Consequently, FMP12 frozen whipped emulsions with surfactants or QH both exhibited superior hardness and overrun, attributed to the presence of fine ice crystals and a stable fat crystal skeleton structure. These findings indicate the prospective utility of QH as a substitute for conventional small chemical emulsifiers, thereby enhancing the quality attributes of plant-based yogurt ice cream.