Bahareh Hajirostamlou - Department of food science and Technology, Neyshabur Branch, Islamic Azad University, Neyshabur, Iran

The yogurt is a complex viscous food material due to the complexity of its nature and composition. The purpose of this work is to comparison of the rheological aspects of blank and fruit yogurt. For this study, two types of yogurt, blank and fruit yogurt (with different concentration of total soluble, fat, protein and sugar content) from the Kaleh Co. (Iran) were analyzed. The study shows the sample with the highest content of fat exhibited the highest viscosity, while the samples with the highest content of sugars presented the lowest level of viscosity. The samples of fruit yogurt seem to have the same viscosity due to the presence of hydrocolloids used to stabilize fruit in the yogurt. The sample with the highest content of fats and fat free samples presented the lowest flow index, while the fruit ones presented the highest flow index. The consistency index, K, is greater for the samples with a lot of fats or without fats, while the samples with fruits presented the lowest index.

blank and fruit yogurt, consistency index, rheological property, viscosity