Study of the variation in viscosity during addition of stabilizers to obtain an optimised reconstituted Indian yoghurt (dahi) powder based drink

Central composite design with two factors (guar gum and locust bean gum) was applied to study the variation of viscosity (dependent variable) with respect to variation of amount of guar gum and locust bean gum (independent variables) where the ratio of dahi powder to water (1:10) was kept constant. Optimisation of thecomposition was carried out, using SAS programming with response surface methodology. All the terms in the final regression equation were found to be significant at α=0.05, except the term presenting the individual effect of locust bean gum. Guar gum was observed to have stronger effect on viscosity of the drink as compared to locust bean gum. The optimum lowest viscosity of 2.003 Pa-s was obtained by incorporating 0.445 g guar gum and 0.905 g of locust bean gum with 20 g of dahi powder and 200 g of water, to prepare the Indian yoghurt drink.