from the (Table 5), it was seen that low-fat yoghurts produced with MWP powders of high N/D whey protein content (Type I, A, C and J) had the highest elastic modulus (G’). There were no significant differences (p < 0.05) when compared with the reference low-fat yoghurt (N02). However none of the low-fat yoghurts resulted in G’ values at the level of the full fat yoghurt (N00).
The heat treatment of the milk chosen in the present study (85 C for 15 min) should ensure extensive whey protein denaturation. A higher proportion of native whey protein in the milk in the yoghurts MI02, MA02, MC02 and MJ02 may have resulted in higher whey protein aggregate formation during heating. The following acidification step promoted the formation of higher number and/or strength of bonds between the whey protein aggregates and the casein micelles.