Formulation and optimization of herb-flavored sweetpotato-chocolate spread

Abstract

The study aimed to formulate and optimize the production process of herb-flavored sweetpotato-chocolate spread. Determination of the right proportions of sweetpotato, cocoa tablet and basil in the production of chocolate spread is necessary in order to produce a finished product which is a highly acceptable and nutritious spread. Plackett-Burman (PB) variable screening design and Response Surface Methodology (RSM) were used as experimental designs. A 33 factorial experiment arranged in Central Composite Design (CCD) with sweetpotato (125, 150 and 175g), cocoa tablet (20, 25 and 30g) and basil (5, 10 and 15g) were used as independent variables.

Results using the Plackett-Burman variable screening showed that cocoa tablet and basil significantly influenced the acceptability of aroma, flavor, aftertaste and general acceptability, while buffalo’s milk, sweetpotato color and cocoa tablet significantly affected the color of the product. Response surface analysis revealed that basil significantly affected the pH, consistency, flavor, taste, aftertaste and general acceptability of herb flavored sweetpotato-chocolate spread. Sweetpotato influenced the cost per 100 g of the finished product. Sweetpotato, cocoa tablet and basil did not significantly affect the TSS, spreadability, color and aroma of the product. Superimposed plots of the different variables indicate that the combination of 150 g sweetpotato, 29 g cocoa tablet and basil was the optimum formulation with a production cost of Php8.00/100g product. The optimum formulation was preferred by 58% of the consumers over the 42% preference on similar commercial chocolate spread. It was found negative of Salmonella and E. coli and had lower microbial count after six weeks of monitoring. The optimized product contained low fat content, low carbohydrates and sugar content but high in dietary fiber. It also contained calcium and potassium.