Viscosity of Doenjang Soup: Exploring How It Shapes Consumer Perception of Kokumi and Mouthfeel

This study investigated how varying viscosity levels in doenjang soup affect consumer perception, focusing on mouthfeel and kokumi, a sensory attribute associated with flavor continuity and richness. Four samples were prepared with increasing concentrations of starch (0%, 0.5%, 1.0%, and 1.5%), and evaluated by 113 Korean consumers using hedonic scales, Just-About-Right (JAR) scaling, Check-All-That-Apply (CATA), and open-ended responses. Results indicated that the 0.5% starch sample received the highest overall liking and mouthfeel liking scores. In contrast, the 1.5% sample was rated significantly lower due to heavy and coating mouthfeel (p < 0.05). PLSR analysis revealed that attributes such as clean and light mouthfeel, tofu aroma, and well-aged appearance were positively associated with consumer acceptance. In contrast, high viscose appearance and dense mouthfeel negatively influenced liking. Although kokumi-related terms (e.g., tofu aroma, umami taste) were more frequently selected in high-viscosity samples, kokumi liking did not significantly differ across conditions. These findings suggest that moderate viscosity enhances mouthfeel and improves overall consumer acceptance without compromising the flavor profile. This study provides new insights into the optimization of sensory characteristics in traditional fermented foods through viscosity control.