Formulation Optimization and Multi-Parameter Evaluation of a Soya-Based Functional Beverage Containing Sweetpotato (Ipomoea batatas) and Mango (Mangifera indica) Puree

The market for functional beverages is expanding, yet lactose-free options that provide a complete profile of essential macronutrients in soya-based beverages remain limited. Hence, this study aimed to evaluate the physico-chemical properties, sensory attributes, and overall acceptability of a soya-based beverage formulated with varying experimental levels of mango puree (10%, 20%, and 30%) and yellow-fleshed sweet potato (10%, 17.5%, and 25%) using a 3×3 factorial design. Sensory data were analyzed through Response Surface Regression Analysis to identify the optimal formulation. Results indicated that increasing the concentration of mango puree had a significant positive linear effect (p<0.05) on the beverage's color, aroma, viscosity, taste, and overall acceptability. Independent of each other, the levels of both mango puree and yellow-fleshed sweet potato significantly affected the total soluble solids (TSS) of the product. However, no significant interaction effects (p>0.05) between the two variables were observed for any other physicochemical characteristics. The optimal beverage formulation, balancing both sensory and physicochemical attributes, was determined to be 21.50% mango puree and 10.40% yellow-fleshed sweet potato. This study demonstrates a viable and highly acceptable method for producing a lactose-free, plant-based beverage that addresses the market's need for functional, nutrient-rich options.