This study aims to investigate the influence of casein and octenyl succinic anhydride modified starch (OSAS) combinations on the physical and oxidative stability of fish oil-in-water emulsions. The interaction between casein and OSAS was manifested in changes in protein structure and hydrogen-bonding interaction. Casein-OSAS combinations could effectively inhibit droplet aggregation at pH 4 and attenuate droplet growth at a high CaCl2 concentration of 0.2 mol/L, compared with casein as an emulsifier. Nanoemulsions stabilized by casein-OSAS combinations or casein showed better oxidative stability compared with OSAS-stabilized emulsions. Therefore, casein-OSAS combinations can improve some physical properties of protein-based emulsions and oxidative stability of modified starch-based emulsions, suggesting protein-modified starch combinations are more promising in the emulsion-based food industry compared to each of the two emulsifiers alone.
Keywords: modified starch; oil-in-water nanoemulsion; oxidative stability; physical stability; protein.