High-protein fat-free acid milk gels: Control of protein composition and heat treatment

Skim milk supplemented with calcium caseinate (Ca-Cas) and whey protein isolate (WPI) at differentratios was preheated at 72e90 C for 7 min and subsequently acidified for the production of set-style andstirred acid gels. Upon heat-treatment of the suspensions, the native whey protein content decreasedand particle size increased with increasing temperature and WPI content. Consequently, the pH ofgelation, firmness of the set gel, viscosity and particle size of the stirred gel all increased as the content indenatured whey protein increased. However, for preheating temperatures of 80 or 90 C, the viscosityand firmness of the gels reached a plateau, although almost all whey proteins were denatured and largestparticles were formed. These results open perspectives for the production of high-protein yoghurtswithout unusual firmness propertie