The interaction between anionic polysaccharides and legume protein and their influence mechanism on emulsion stability

Abstract

Legume proteins have excellent emulsification, but the utmost problem is the poor emulsion stability of single protein. In this study, three anionic polysaccharides (xanthan (XG), Willan (WG) and gellan (GG)) were selected to improve stability of protein emulsion (soy protein (SPI), mung bean protein (MPI) and pea protein (PPI)). Molecular interaction, stability, interfacial adsorption, rheology and microstructural characteristics of emulsions were analyzed. The result shown that MPI-polysaccharide emulsion had the smallest particle size and GG-protein emulsion had higher the zeta-potential, and XG-MPI had the best stability. The emulsifying activity and emulsifying stability of GG-SPI were found to be best, the fastest adsorption rate was observed for GG-SPI (AP% 45.23%, Γ 5.03 mg/m2). Fluorescence spectroscopy and gel electrophoresis showed that polysaccharide linked by protein were mainly ascribed to noncovalent interactions and had little effect on the microenvironment. The particle size distributions of SPI group were most homogeneous, and PPI group had obvious aggregation observed by CLSM. All emulsions were pseudo-plastic and shear-thinning properties. XG-MPI and GG-SPI showed better stability and emulsifying properties, polysaccharide promoted the absorption of protein on the oil droplet surface by increasing negative charges repulsive interaction and emulsion viscosity. In brief, the interaction between legume protein and anionic polysaccharide changed the emulsion stability. The research would enriched the emulsions applications in food processing.