Effect of carbohydrates on the emulsifying, foaming and freezing properties of whey protein suspensions

The aim of this study was to examine interactions between whey proteins (whey protein isolate (WPI), whey protein concentrate (WPC) and beta-lactoglobulin) and carbohydrates (glucose, sucrose, starch and inulin) on some physical and functional properties of whey proteins and carbohydrates suspensions (10% dry matter (w/v)). Model systems were therefore investigated related to their foam expansion and foam stability. Carbohydrate addition in model suspensions of whey proteins resulted in significantly (P < 0.05) enhanced foam stability of protein suspensions (FSI; MFS). Model systems were also analyzed for emulsion activity index (EAI) and emulsion stability index (ESI) by the turbidometric technique. EAI and ESI values increased significantly (P < 0.05) in model suspensions prepared with WPI and beta-lactoglobulin in combination with mono and disaccharides, while significant decrease (P < 0.05) were remarked in model suspensions prepared with inulin and starch addition. The phase-transition temperatures of investigated model systems were determined using differential thermal analysis with continuous scanning. In all model suspensions, significant lowering (P < 0.05) of initial freezing temperature has occurred. (c) 2006 Elsevier Ltd. All rights reserved.