Influence of environmental stresses on stability of oil-in-water emulsions containing droplets stabilized by β-lactoglobulin-ι-carrageenan membranes

An oil-in-water emulsion (5 wt% corn oil, 0.5 wt% β-lactoglobulin (β-Lg), 0.1 wt% ι-carrageenan, 5 mM phosphate buffer, pH 6.0) containing anionic droplets stabilized by interfacial membranes comprising of β-lactoglobulin and ι-carrageenan was produced using a two-stage process. A primary emulsion containing anionic β-Lg coated droplets was prepared by homogenizing oil and emulsifier solution together using a high-pressure valve homogenizer. A secondary emulsion containing β-Lg-ι-carrageenan coated droplets was formed by mixing the primary emulsion with an aqueous ι-carrageenan solution. The stability of primary and secondary emulsions to sodium chloride (0-500 mM), calcium chloride (0-12 mM), and thermal processing (30-90 °C) were analyzed using ζ-potential, particle size and creaming stability measurements. The secondary emulsion had better stability to droplet aggregation than the primary emulsion at NaCl ⩽ 500 mM, CaCl2 ⩽ 2 mM, and holding temperatures ⩽60 °C for 20 min. The interfacial engineering technology used in the study could therefore lead to the creation of food emulsions with improved stability to environmental stresses.