Disulfide-mediated Polymerization Reactions and Physical Properties of Heated WPI-stabilized Emulsions |
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Authors: | FJ MONAHAN DJ McCLEMENTS JB GERMAN |
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Affiliation: | Author Monahan is with the Dept. of Food Science, Univ. College Dublin, Belfield, Dublin 4, Ireland. Author McClements is with the Dept. of Food Science, Univ. of Massachusetts, Amherst, MA 01003. Author German is with the Dept. of Food Science&Technology, Univ. of California, Davis, CA 95616. |
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Abstract: | Heating a 19 wt% corn oil-in-water emulsion stabilized by 1 wt% whey protein isolate from 30 to 70°C and then cooling to 25°C for at least 15 hr, brought about minimal changes in droplet aggregation, apparent viscosity and susceptibility to creaming. At 75°C, droplet aggregation occurred but this decreased on heating to 90°C. The apparent viscosity and susceptibility of droplets to creaming increased as the degree of droplet aggregation increased. Inclusion of the sulfhydryl blocking agent N-ethylmaleimide to inhibit thiol/disulfide interchange reactions did not affect droplet aggregation but resulted in higher apparent viscosity values and susceptibility to creaming at 85 and 90°C and not at lower temperatures. The results suggest that droplet aggregation results from noncovalent interactions between unfolded protein molecules adsorbed on different droplets and that the interactions are strengthened by disulfide bonds. |
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Keywords: | corn oil emulsion whey protein aggregation sulfhydryl |
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