Exploring the relationship between physicochemical stability and interfacial properties in pea/whey protein blend-Stabilised emulsions

The interfacial behaviour of pea/whey protein blends, enzymatically cross-linked using microbial transglutaminase, and with addition of maltodextrin, was investigated to understand the physicochemical stability of O/W emulsions. Enzymatic cross-linking led to the reduction of oil droplet size by unfolding of cross-linked protein structure, while maltodextrin improved the physicochemical stability of β-carotene emulsions by forming sterically stable emulsions. The combined treatment of enzymatic cross-linking and maltodextrin addition led to excellent emulsion stability, protecting the emulsions from flocculation and coalescence. Enzymatic cross-linking lowered the viscosity and elasticity at oil/water interface with gradual and continuous adsorption, while maltodextrin addition did not impact the interfacial rheological properties. Enzymatic cross-linking promoted initial adsorption of whey proteins, especially β-lactoglobulin, while maltodextrin reduced the displacement of adsorbed pea proteins by whey proteins. Enzymatic cross-linking also led to the exposure of tryptophan residues and increase of β-sheet content, indicating the alteration of secondary and tertiary structures of pea/whey protein blends. Maltodextrin had an indirect effect on protein secondary structure changes at oil/water interface, related to improved binding affinity of proteins in the presence of maltodextrin. Thus, strategies including enzymatic cross-linking and maltodextrin addition could improve the emulsion stability of mixed protein systems by altering their adsorption behaviour and interfacial properties at the oil/water interface, expanding their applications in food processing.