STRUCTURE-MECHANICAL PROPERTIES OF HEAT-INDUCED WHEY PROTEIN CASSAVA STARCH GELS/

Structure-mechanical properties of heat-induced whey protein isolate/c assava starch (WPI/CS) gels were studied by hot-stage video microscopy (HSVM) and axial compression testing (ACT). Elastic moduli (or compre ssion stress) of pure WPI and CS gels followed a power dependence with concentration. ACT confirmed that reinforcement occurred when CS was added at 10-25% of total solids. HSVM revealed that CS granules swelle d first, removed water from the system and concentrated the WPI soluti on that gelled later. Reinforced gels had a continuous WPI phase fille d with swollen CS granules. A modified Takayanagi model accounting for water redistribution during gelatinization accurately fitted the mech anical properties of these gels.