CA2+-INDUCED GELATION OF PRE-HEATED WHEY-PROTEIN ISOLATE

Addition of CaCl2 to pre-heated whey protein isolate (WPI) suspensions caused an increase in turbidity when pre-heating temperatures were greater-than-or-equal-to 64-degrees-C. Pre-heating to greater-than-or-equal-to 70-degrees-C was required for gelation. WPI suspensions which contained CaCl2 became turbid at 45-degrees-C and formed thermally induced gels at 66-degrees-C. Thermally and Ca2+-induced gels showed significant time/temperature effects but the penetration force values in the Ca2+-induced gels were always lower. However, Ca2+-induced gels were higher in shear stress at fracture. The Ca2+-induced gels had a fine-stranded protein matrix that was more transparent than the thermally induced gels, which showed a particulate Microstructure.