Optimization of seabuckthorn fruit yogurt formulation using response surface methodology.

The response surface methodology was used to optimize the formulation of seabuckthorn fruit yogurt. The independent variables were proportions of seabuckthorn fruit syrup and skimmed milk powder. The responses were counts of Streptococcus thermophilus and Lactobacillus bulgaricus, taste and viscosity of the product. Statistical analysis revealed that fruit syrup and skimmed milk powder significantly affected all the responses. Contour plots for each response were used to generate an optimum area by superimposition. Optimum formulation conditions of fruit syrup (15 %) and skimmed milk powder (12.5 %) are recommended for the blend formulation yielding an acceptable and good quality seabuckthorn fruit yogurt. Model validation was conducted using separate experiments at optimum conditions. The experimental values were found to be in close agreement to the predicted values and were within the acceptable limits indicating the suitability of the model in predicting quality attributes of seabuckthorn fruit yogurt. The resultant product also exhibited more amounts of fat, protein, carbohydrate and antioxidants viz., vitamin C, E, carotenoids, phenols and anthocyanins when compared to a commercial one.