Comparative study of the chemical profile, antioxidant properties, and sensory profile of soy-based and non-soy sweet soy sauces

Abstract

This study aimed to evaluate the physicochemical characteristics, antioxidant activity, and sensory attributes of sweet soy sauce made from soybean- and non-soybean-based ingredients as part of developing alternative local functional foods. The samples analyzed included black soybean, pigeon pea, coconut water, coconut sap, sorghum, and sweet sorghum nectar-based sweet soy sauces. Physicochemical analyses included measurements of moisture content, reducing sugars, protein, and total dissolved solids (°Brix). Antioxidant activity was assessed through total phenolic content and DPPH radical inhibition. Sensory evaluation involved both hedonic and descriptive analysis using the Rate All That Apply (RATA) method. Results showed that sorghum and sweet sorghum nectar sauces had the highest total dissolved solids (77.1% and 77.0%, respectively), while the highest total phenolic content was found in the sweet sorghum nectar sauce (23.50 mg GAE/g). The highest antioxidant activity was recorded in the black soybean sauce (81.13%). Sensory-wise, the sorghum-based sauce received the highest overall hedonic value of 7.23 (categorized as "liked") and the highest ratings for sweet taste, umami, viscosity, and thick mouthfeel. In contrast, the coconut water-based sauce showed the lowest performance in sensory attributes, particularly in viscosity and taste intensity, making it less preferred by panelists.