Production of synbiotic Doogh enriched with Plantago psyllium mucilage

Physical instability and loss of viability of probiotic bacteria are the most important problems in production of synbiotic Doogh. Some plant hydrocolloids have been recognised as effective components to prevent these problems. In this study the effect of Plantago psyllium mucilage ( PP M) (0, 0.15%, 0.30%, 0.75% (w/w) on the physicochemical, microbial, and sensory properties of Doogh samples was evaluated by measuring phase separation, viscosity, flow behaviour, probiotic viability and sensory parameters. The results revealed that the stability of samples containing PP M were higher than samples without this hydrocolloid. By increasing the amounts of PP M, the viscosity of treated samples were increased compared to control sample. Herschel-Bulkley rheological model was an appropriate model for describing the flow behavior of Doogh formulated with PP M and the power-law rheological model was suitable model for describing the flow behavior of control samples. PP M had non-digestible food ingredients and improved the viability of Lactobacillus casei ; therefore, this herbal mucilage may have prebiotic potential. Finally, the samples treated with 0.30% PP M on the 15 th day were chosen as the best formulation for the production.