Rheological properties of probiotic non-fat yogurt containing Lactobacillus reuteri: Effects of inulin addition, inoculum level and fermentation temperature

The simultaneous effects of inulin addition (0-4%w/w), probiotic inoculum level (1-3%v/v) and fermentation temperature (37-45°C) on the dynamic rheological properties of probiotic non-fat yogurt were studied using response surface methodology. Frequency sweep tests were performed to measure structure strength and type of structure. Linear viscoelastic range in term of strain (LVE), structure strength (G¢ at LVE), yield stress (τy) and flow point (τf) of samples were measured doing strain sweep test. Results showed that Inulin concentration had the greatest influence on G' and τf, followed by fermentation temperature. A positive correlation between b value and level of syneresis was observed.