Effect of β-glucan Exopolysaccharide on Physicochemical Properties of Low-Fat Set Sheep's Milk Yogurt

Beta-glucan composite is a dietary fiber and has beneficial health effects that can be used as a prebiotic and fat replacer in the manufacture of dietary products such as low-fat yogurt.  The purpose of this research is to use beta-glucan exopolysaccharide in amounts of 0.1, 0.2, 0.3 and 0.4% (w/w) in the production of low-fat shaped sheep yogurt. And also, physicochemical (pH, % acidity, % total solids) and survival of starter cultures of treatments were determined during 21 days of storage period. Experiments were performed in a factorial form in a completely randomized design with the software of SPSS 16.0. Parallel to decreasing in pH, the acidity of all samples were increased significantly (p<0.05). The beta glucan concentration did not have significant effect on total solid amounts (p>0.05). Increase of beta glucan levels in yogurt formulation led to decrease syneresis however, the viscosity was increased. During storage, viscosity significantly was increased (p<0.05), but syneresis of all samples was decreased except for control sample. The concentration of beta glucan had not significantly effect on survival rate of both starter bacteria(p>0.05).  Finally, it concluded that beta glucan was the best fat replacer and could be used in formulation of yogurt with sheep milk. Addition of beta glucan at 0.2 and 0.3% levels had a good potential for being used as a stabilizer in yogurt formulation. The sample containing 0.3% beta glucan can be introduce as the best treatment.