Formation and creaming stability of alginate/micro-gel particle-induced gel-like emulsions stabilized by soy protein isolate

Many strategies have been developed to improve stability of plant protein-stabilized emulsions, such as modifying properties of plant proteins, using plant protein-polysaccharide complexes, and forming gel-like emulsions. In this study, a novel method was investigated to enhance creaming stability of soy protein isolate (SPI)-stabilized emulsions by introducing alginate and alginate-based micro-gel particles to form gel-like emulsions. Gel-like emulsions could be obtained at high levels of micro-gel particles (>6.0%) in the presence of alginate (>0.1%), while the concentration of SPI-coated droplets (0–10%) played a relatively unimportant role, probably because the gelation mechanism was interactions between alginate molecules and Ca²⁺-induced micro-gel particles. Viscosity and creaming stability of emulsions and storage modulus (G′) of gel-like emulsions increased with increasing contents of micro-gel particles in emulsions. Emulsions without micro-gel particles showed extensive creaming during storage, and emulsions containing micro-gel particles were visually stable after storage for six weeks, although all samples showed good stability to coalescence. In addition, the presence of micro-gel particles in emulsions slightly decreased the bioaccessibility of encapsulated lycopene after in-vitro digestion. The method presented in this study was important for improving creaming stability of plant protein-stabilized emulsions and expanding application of plant protein-stabilized emulsions in food industry.