Emulsifying properties of caprine and bovine whey protein concentrates: Effects of proteins concentration and oil-phase volume fraction

Abstract

The objective of this study was to evaluate the emulsifying capacity of caprine whey protein concentrate (WPCC), obtained at laboratory scale, and to compare it with commercial bovine whey protein concentrate (WPCB). The effect of the WPC (whey protein concentrate) concentration (1%, 2% and 3% w/v) and the volumetric fraction of the oil phase (Ф) (0.2, 0.4 and 0.6) in oil-in-water (O/W) emulsions prepared at pH 7 were studied. In this research emulsifying properties (emulsifying activity index (EAI m2/g), emulsion stability index (ESI hr), creaming index (CI %)) and interface attributes (interfacial concentrations of proteins, SDS-PAGE profiles of adsorbed proteins and ζ-potential) of WPC caprine and bovine were assessed. The results indicate that WPCC has good emulsifying capacity even at low concentration (1% w/v), achieving a maximum EAI of 30.25 ± 4.96 m²/g (vs. 21.01 ± 0.98 m²/g for WPCB) at Ф= 0.2, and presented lower CI (≈ 20%) at Ф =0.6 compared to WPCB (37%) and regarding ESI values, there were practically no differences between both WPCs. The ζ-potential values were similar between both emulsifiers (approximately ≈ -20mV). Protein adsorption at the oil–water interface was lower for both WPCC and WPCB.These results suggest that WPCC exhibits promising emulsifying properties compared to WPCB and may be considered a functional alternative for food formulations, especially for those foods that require specific proteins to improve emulsifying and nutritional properties.