Physicochemical, texture properties, and microstructure of yogurt using polymerized whey protein directly prepared from cheese whey as a thickening agent

The aim of this study was to investigate suitability of polymerized whey protein prepared directly from cheese whey on the physicochemical, texture properties, and microstructure of the yogurt. The results indicated that addition of polymerized whey protein obtained by heating the liquid whey protein concentrate at 75 degrees C for 10 min had no significant differences in pH, titratable acidity, total solids, protein content, viscosity, texture, and syneresis between the yogurt with polymerized liquid whey protein (YWPS) and the yogurt with polymerized whey protein concentrate. However, the YWPS had significant differences in viscosity, texture, and syneresis compared with the control yogurt. Scanning electron micrographs of YWPS displayed a compact and homogeneous protein network for polymerized whey protein solution (PWPS) samples. The 4 yogurt samples were evaluated by the quantitative descriptive analysis method, and 14 sensory attributes were analyzed by principal component analysis. All 3 principal components had significant effects on the sensory profiles, accounting for 52.3, 24.32, and 10.8% of the variability in the results, respectively. Polymerized whey protein prepared directly from cheese whey may be a good protein base as a thickening agent for yogurt making.