Impact of protein-providing milk ingredients on volatile compounds, microstructure, microbiology and physicochemical characteristics of yogurts

The impact of skim milk (SM), demineralized whey (DW), whey protein concentrate (WPC40-WPC80), isolated (WPI) and hydrolyzed (WPH) on different parameters of yogurts have been evaluated using SLB95 and Yoflex starters. Addition of whey proteins shortened the fermentation time in yogurts with the exception of WPH, which extended it and presented the highest titratable acidity. WPH increased the Lactobacillus and decreased Streptococcus population in yogurts with SLB95 starter. WPI and WPC80 increased water-holding capacity. WPI and WPC80 yogurts exhibited larger aggregates, compared to the rest ingredients, and be bigger with the SLB95 starter. The volatile compounds differ, though not greatly, among yogurts.