Combined effect of denatured whey protein concentrate level and fat level in milk on rennet gel properties

A factorial experimental design was used to evaluate the effect of denatured whey protein and fat concentrations in milk on rennet gel properties. The coagulation properties were characterized by dynamic rheometry. Decreased coagulation rate and storage modulus (G') were observed when denatured whey protein concentrate (DWPC) was added to milk. Increasing the fat content barely affected milk coagulation, with a slight decrease in G' at 60 min. The contraction kinetics of the gels during cooking was also characterized. Only the increase in DWPC reduced the contraction capacity of the gel. The use of DWPC in miniature cheese production linearly increased cheese yield and moisture. Introducing DWPC did not reduce fat retention in the curd, except at 0.75% when combined with the highest fat level (3.4%). Fat globules and DWPC aggregates are both considered to be fillers in rennet gels, but our results clearly show different impacts on gel mechanical properties.