Effects of various whey proteins on the physicochemical and textural properties of set type nonfat yoghurt

In this study, the changes during storage in the physicochemical, textural and sensory properties of nonfat yoghurts fortified with whey proteins, namely whey protein concentrates (WPC), whey protein isolates and whey protein hydrolysates, were investigated. Enrichment of nonfat yoghurt with the whey protein additives (1% w/v) had a noticeable effect on pH, titratable acidity, syneresis, water-holding capacity, protein contents and colour values on the 14th day of storage (P<0.01). The addition of whey proteins to the yoghurt milk led to increases in the hardness, cohesiveness and elasticity values, resulting in improved textural properties. The addition of WPC improved the texture of set-type nonfat yoghurt with greater sizes in the gel network as well as lower syneresis and higher water holding capacity. This study suggests that the addition of whey protein additives used for fortification of yoghurt gave the best textural and sensory properties that were maintained constant during the shelf life.