Improvement of physical properties of nonfat fermented milk drink by using whey protein concentrate

The use of whey protein concentrate (WPC) for the improvement of physical properties of nonfat fermented milk drink was investigated. Drinks were prepared from nonfat milk powder and WPC at different proportions. Rheological properties, serum separation and particle size of the drinks were measured. The effect of WPC on the physical properties of the drinks was evaluated by comparison with those of commonly used stabilizers, including propylene glycol alginate and locust bean gum. WPC addition caused an increase in the consistency coefficient and thixotropy and a decrease in the particle size of the samples. There was no serum separation in the sample with 2% WPC. Large unstable aggregates were observed in the sample with 3% WPC, which also exhibited the highest serum separation. WPC up to a level of 2% positively influenced the physical properties of nonfat fermented milk drink similar to stabilizers.