Influence of pH and pectin type on properties and stability of sodium-caseinate stabilized oil-in-water emulsions

Influence of pH value and locust bean gum concentration on the stability of sodium caseinate-stabilized emulsions

“…This is expected since this pH value is quite close to the isoelectric point of adsorbed proteins (pH 4.6). The reduction in the charge of the protein, decreases the electrostatic repulsion between the droplets, allowing the attractive forces between them to dominate (Perrechil, et al, 2010;Surh, et al, 2006). In most cases, the higher concentrations of LBG as a thickening agent noticeably decreased the volume-weighted mean diameter ( As discussed in the introduction, we believe that most, if not all of the LBG resides in the bulk, due to its competitive adsorption with the significantly more surface active CAS.…”

“…The results suggest that CAS-stabilized emulsions prepared at pH 5.0 are extremely susceptible to the gravitational separation. The reason for this can be explained by the fact that at pH value very close to the isoelectric point of adsorbed proteins (pH 4.6), the net attractive forces between casein molecules increases, leading to the decreased electrostatic repulsion, and consequently CAS-coated oil droplet aggregation (Perrechil, et al, 2010;Surh, et al, 2006). The droplet aggregation, e.g., flocculation and coalescence, may enhance creaming rate by increasing the oil droplet size (McClements, 2005).…”

“…Furthermore, caseins form a thick protective layer of up to 10 nm around the oil droplets as compared with other milk proteins, e.g. whey proteins with only a layer of thickness 1-2 nm (Surh, Decker, & McClements, 2006). The thick interfacial layer confers strong and long ranged steric repulsion on the freshly formed oil droplets and protects fine droplets against flocculation and hence coalescence (Dickinson, 1999;Surh, et al, 2006).…”

“…whey proteins with only a layer of thickness 1-2 nm (Surh, Decker, & McClements, 2006). The thick interfacial layer confers strong and long ranged steric repulsion on the freshly formed oil droplets and protects fine droplets against flocculation and hence coalescence (Dickinson, 1999;Surh, et al, 2006). Caseinate (CAS) covered emulsions are more stable to elevated temperature treatments when compared with whey protein stabilized emulsions since in contrast to the globular proteins, e.g., whey proteins, casein molecules are relatively flexible and do not develop heatinduced structural changes (McClements, 2004;Surh, et al, 2006).…”

“…The thick interfacial layer confers strong and long ranged steric repulsion on the freshly formed oil droplets and protects fine droplets against flocculation and hence coalescence (Dickinson, 1999;Surh, et al, 2006). Caseinate (CAS) covered emulsions are more stable to elevated temperature treatments when compared with whey protein stabilized emulsions since in contrast to the globular proteins, e.g., whey proteins, casein molecules are relatively flexible and do not develop heatinduced structural changes (McClements, 2004;Surh, et al, 2006). One drawback of CAS-stabilized emulsion is their susceptibility to droplet flocculation at pH close to the isoelectric point (pH 4.6) of the casein since this drastically reduces the electrostatic repulsion between the oil droplets (Perrechil & Cunha, 2010;Surh, et al, 2006).…”