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% beta-lactoglobulin (beta-Lg), 0.1 wt% iota-carrageenan, 5 mM phosphate buffer, pH 6.0) containing anionic droplets stabilized by interfacial membranes comprising of P-lactoglobulin and iota-carrageenan was produced using a two-stage process. A primary emulsion containing anionic beta-Lg coated droplets was prepared by homogenizing oil and emulsifier solution together using a high-pressure valve homogenizer. A secondary emulsion containing beta-Lg-iota-carrageenan coated droplets was formed by mixing the primary emulsion with an aqueous iota-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 degrees C were analyzed using zeta-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 degrees 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. (c) 2005 Elsevier Inc. All rights reserved.