Influence of xanthan gum on properties and stability of oil-in-water Pickering emulsions stabilized by zein colloidal particles

Abstract

Influence of xanthan gum (XG) concentration (0–0.5%) on physical and rheological properties and stability of oil-in-water (O/W) Pickering emulsions stabilized by zein colloidal particles was investigated. Protein zein interacted with XG in solution from pH 3.0 to 9.0. The isoelectric point of zein was 6.2. At pH 5.5, electrostatic and steric repulsion between droplets increased whereas droplet size and degree of droplet flocculation decreased with increasing XG concentration, resulting in an increase in emulsion stability against creaming. At 0.1% XG, the emulsions were highly unstable due to the effective size of flocculated droplets was so large that the viscosity was not high enough to prevent the flocs movement. At 0.5% XG, however, the emulsions were highly stable due to the formation of gel-like structures which immobilized the oil droplets. This study demonstrates an importance of polysaccharide concentration on the improvement of emulsion stability. Graphical abstract: [Figure not available: see fulltext.]