Droplet and creaming stability of fish oil-loaded gelatin/surfactant-stabilized emulsions depends on both the adsorption ways of emulsifiers and the adjusted pH

Abstract

The droplet and creaming stability of food emulsions stabilized by mixed emulsifiers is a research hotspot in the field of emulsions. In this work, we mainly explore the effect of pH change on the droplet and creaming stability of fish oil-loaded emulsions synergetically (Span 80 and SL) or competitively (Tween 80 and SDS) stabilized by gelatin/surfactant. The results demonstrate that initial droplet stability and droplet storage stability, and creaming stability of the pH-adjusted emulsions are dependent on both the adsorption ways of emulsifiers and the adjusted pH: (1) Competitively stabilized emulsions have more stable droplets than synergetically stabilized emulsions; (2) SDS-dominant competitively stabilized emulsions have more stable droplets than gelatin-dominant emulsions; (3) Basic pH-adjusted emulsions have more stable droplets than acidic pH-adjusted emulsions; (4) The synergetically stabilized emulsions at acidic pH have significantly higher creaming indexes than that at basic pH; and (5) The competitively stabilized emulsions have high or similar creaming indexes to that at acidic pH. Further, the mechanisms are proposed according to Stokes’ Law. This work will provide useful information to understand the interfacial properties of mixed emulsifiers in the food emulsions and promising application perspective for the development of food beverages including acidic and alkali beverages.