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Y. S. GU, E. A. Decker, and D. J. McClements. Dept. of Food Science, Univ. of Massachusetts, Amherst, 238 Chenoweth Lab., Amherst, MA 01003 A novel interfacial engineering technology, based on electrical layer-by-layer deposition has been developed to increase the stability of emulsions such as thermal processing, freeze-thaw cycling, lipid oxidation and high ionic strength. We utilized this technology to create novel food emulsions stabilized by beta-Lg-iota-carrageenan membranes that have much improved resistance to environmental stresses. The specific objective of this study is to characterize emulsion formation and compare the stability of emulsions stabilized only with beta-Lg membranes with those stabilized by beta-Lg-iota-carrageenan membranes to pH, salts, thermal processing, and freeze-thaw cycling. A primary emulsion containing anionic beta-Lg coated droplets (5 wt% corn oil, 0.5 wt% beta-Lg, 5 mM phosphate buffer, pH 6.0) 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 (5 wt% corn oil, 0.5 wt% beta-Lg , 0.1 wt% iota-carrageenan, 5 mM phosphate buffer, pH 6.0) was formed by mixing the primary emulsion with an aqueous iota-carrageenan solution. The stability of primary and secondary emulsions to sodium chloride (0 to 500 mM), calcium chloride (0 to 12 mM), thermal processing (30 to 90 ºC), and freeze-thaw cycling –20o C for 22 hrs / 300 C for 2 hs) 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 8804; 500 mM, CaCl2 ≤ 2 mM, holding temperatures ≤ 60 ˚C for 20 min, and to freeze thaw cycling. The interfacial engineering technology used in the study could therefore lead to the creation of food emulsions with improved stability to environmental stresses.
Session 32, Food Chemistry: Component interactions and processing effects
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |