Rheological properties of plain yogurt during coagulation process: impact of fat content and preheat treatment of milk

A study of the effect of fat content and preheat treatment of milk has show n their respective effects on the rheological behavior of curd during the c oagulation process of plain yogurt. Increase in fat content leads to an inc rease in viscosity. The highest viscosity was manifested by milk heated at 137 degrees C while the lowest value was exhibited by milk heated at 65 deg rees C. The process viscosity curves for three different stages are describ ed by mathematical relationships. Finally, a two-parameter power law model was used to describe the flow behavior of the yogurt during coagulation. (C ) 2000 Elsevier Science Ltd. All rights reserved.