Effect of processing and storage on rheological properties of fortified milk and curd systems

Summary Fortified milk systems were prepared by blending pasteurized standardized milk with skim milk powder, peanut flour or peanut protein isolate to 15, 18, 20, and 23% total solids followed by processing at 60°C and 80°C for 30min and storage at 4°C for 24h. Curds were prepared by the lactic fermentation of the processed milk systems. The rheological properties showed that all the systems exhibited pseudoplastic flow. The flow became less Newtonian with increasing total solids, heat treatment, and storage. Curd obtained from the fortified milk processed at 80°C showed increased yield stress and curd strength with the increasing concentration. Degree of heat treatment, total solids content and storage were shown to have a pronounced effect on the apparent viscosity, consistency index, and yield stress of the fortified milk systems.