Influence of sucrose on NaCl-induced gelation of heat denatured whey protein solutions

A solution of heat-denatured whey proteins was prepared by heating 10 wt.% whey protein isolate at pH 7.0 to 80 degrees C for 10 min in the absence of salt. This treatment caused the globular protein molecules to partially un fold and aggregate. When the heat-denatured whey protein solution was coole d to room temperature and mixed with 200 mM NaCl it formed a gel. The influ ence of sucrose (0 to 10 wt.%) in the protein solutions prior to NaCl addit ion on the gelation rate was investigated. At relatively low concentrations (0-8 wt.%) sucrose decreased the gelation rate, presumably because sucrose increased the aqueous phase viscosity. At higher concentrations (> 8 wt.%) sucrose increased the gelation rate, probably because it decreased the the rmodynamic affinity of the globular proteins for the aqueous solution, whic h increased the attraction between proteins. This data has important implic ations for the application of cold-setting whey protein ingredients in swee tened food products such as deserts and beverages. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.