Rheological and sensory properties and syneresis of set yogurt produced with exopolysaccharide producing starter culture YF-L811

Several strains of lactic acid bacteria, used as starter culture to produce yoghurt and other fermented products, produce exopolysaccharides which can improve textural properties of products. In this study, physical (syneresis), rheological (viscosity and firmness) and sensory properties of yoghurt samples produced with exopolysaccharide producing starter culture were investigated in comparison with nonexopolysaccharide producing starter culture CH-1 during 30 days of storage. Samples with exopolysaccharide producing starter culture had lower syneresis and were more viscous and firmer than those made with nonexopolysaccharide producing starter culture. Storage time had significant (P<0.001) effect on mentioned properties. Panelists expressed that yoghurts produced with YF-L811 were whiter, firmer and had lower syneresis before and after inserting spoon into them, stronger flavor and tended to be creaminess, more cohesive and adhesive than samples produced with CH-1. Difference between unpleasant sourness of samples produced with exopolysaccharide producing starter culture and nonexopolysaccharide producing starter culture was not significant (P>0.05).