Rheological and Sensory Assessment of Soy-chocolate Drinks as Influenced by Sugar, Cocoa Powder and Fortificants

Abstract

Effects of sugar, cocoa powder and fortificants on the rheological and sensory characteristics of soy-chocolate drinks were evaluated. Randomized sensory testing yielded 2 most preferred plain and sweetened sample formulations. Triple fortification of soy- chocolate drinks with 0.15 mg potassium iodide, 2.0 mg ferrous sulphate, 1.6 mg pro- vitamin A (retinol palmitate) / 100g sample was used as recommended by the world health organization [WHO, FAO 2021] and food fortification regulations guidelines (2021). Four soy-chocolate drinks comprising of non-fortified plain (NFPSCD), fortified plain (FPSCD), non-fortified sweetened (NFSSCD) and fortified sweetened (FSSCD) were formulated. The viscosity of soy-chocolate drinks as influenced by sugar, cocoa powder and fortificants reduced (7- 25) significantly (p< 0.05) with increased shear rate and temperature. The power law regression analysis indicates that soy-chocolate drink is non- Newtonian since its flow behavior index, n (0.81- 0.97) is less than one. The fortified samples FSSCD (5.9 - 8.4) and FPSCD (7.0 - 7.3) had highest score than the non-fortified samples NFPSCD (5.3 - 5.8) and NFSSCD (5.4 - 5.7) for flavor, color, taste, mouthfeel and general acceptability. Sensory qualities of food formulations are a close representation of preference for target groups when testing for acceptability of food products. It was observed from this study that formulated soy- chocolate drinks are pseudo-plastic.