Effect of heating milk on whey protein denaturation and cheese-making properties

The cheese-making properties of milk heated at 80 °C for different times (0–8 min), and mixtures of severely-heated milk (80 °C, 30 min) with non-heated milk were evaluated in separate experiments. In both approaches, milk pH was adjusted to 6.3, 6.7 or 7.0 before heating. Despite different distributions of denatured whey protein (WP) between casein micelle surface and serum phase, heating pH had no significant effect on cheese-making properties. The two approaches were compared by reporting the results as a function of WP denaturation rate in milk. The mixed milk approach showed a higher detrimental effect on rennet-induced coagulation kinetics and curd contraction capacity during cooking than the heated milk approach. For similar WP-denaturation rate, higher yield was obtained for the mixed milk than the heated milk as a result of the better protein retention and larger increase of cheese moisture.