High-protein fat-free acid milk gels: Control of protein composition and heat treatment
Résumé
Skim milk supplemented with calcium caseinate (Ca-Cas) and whey protein isolate (WPI) at different
ratios was preheated at 72e90 C for 7 min and subsequently acidified for the production of set-style and
stirred acid gels. Upon heat-treatment of the suspensions, the native whey protein content decreased
and particle size increased with increasing temperature and WPI content. Consequently, the pH of
gelation, firmness of the set gel, viscosity and particle size of the stirred gel all increased as the content in
denatured whey protein increased. However, for preheating temperatures of 80 or 90 C, the viscosity
and firmness of the gels reached a plateau, although almost all whey proteins were denatured and largest
particles were formed. These results open perspectives for the production of high-protein yoghurts
without unusual firmness properties