Effects of heating temperatures and pH of skim milk fortified with milk protein concentrate on the texture and microstructure of high-protein yoghurts

Texture and microstructure of high-protein yoghurts manufactured from milk protein concentrate (MPC) fortified skim milk heated at different temperatures (75, 80, 85, 95 °C for 10 min) and pH (6.5, 6.7, 6.9, 7.1) were studied. Whey protein (WP) denaturation increased from 16% to 89% with increasing heating temperatures, while WP binding to casein micelles decreased from 95% to 21% with increasing heating pH. Gelation pH during fermentation increased with increasing heating temperatures and pH. Gel network became denser when heating temperatures and pH increased. Firmness and coagulum particle size of yoghurts increased with increasing heating temperatures and pH. Water-holding capacity reached above 87%, and increased slightly with increasing heating temperatures and pH, followed by slight decreases during storage. Reducing heating temperatures and pH of milk base offers potential strategies to obtain a desirably smooth texture without excessive syneresis for high-protein yoghurts manufactured by concentration before fermentation.