Production and characterization of synbiotic Doogh, a yogurt-based Iranian drink by gum arabic, ginger extract and B. bifidum

The objective of this study was to determine the effects of using ginger extract and gum arabic as a prebiotic on the viability of Bifidobacterium bifidum and physico chemical properties of Doogh (yogurt drink) during storage at 4 °C for 30 days. The results showed that by increasing the amounts of gum arabic to 0.5%, B. bifidum count increased significantly ( P  < 0.05), but further increasing of the gum arabic, had no significant effect on B. bifidum count ( P  > 0.05). By increasing the amounts of gum arabic, the viscosity of the Doogh samples was increased and phase separation was reduced significantly ( P  < 0.05). The Doogh sample containing 0.25% gum arabic and 0.25% ginger extract had the highest number of probiotic population. Results showed that addition of B. bifidum  increased acid development (°D) in Doogh samples during storage. In addition, phase separation in Doogh enriched by gum arabic was slower compared to control sample and the samples containing ginger extract. Doogh samples containing 0.25-1% gum arabic alone showed acceptable stability during storage time at 4 °C. In general, Doogh sample containing 0.25% ginger extract and 0.5% gum arabic gained the highest overall acceptability score in comparison with the other samples.