Soy protein is a common nutrient source in plant-based foods including protein bars, yet high concentrations often introduce off-flavors that reduce consumer acceptability. This study investigated the partial substitution of soy protein with oat flour (0, 15, and 30 g; samples SO 0 , SO 15 , SO 30 ) and the addition of cocoa (CSO 0 , CSO 15 , CSO 30 ) to mitigate off-flavors while improving textural, nutritional, and antioxidant properties of the snack bars. Proportional increases of oat flour significantly ( p < 0.05) improved the texture of both original- and cocoa-flavored bars. Compared to the oat-free controls, hardness was reduced by 1.85- to 2.02-fold, while post-baking expansion increased 1.37- to 1.45-fold. Significant decreases in volatile compounds including 2-pentyl furan (from 9.80 – 14.52 % to 3.78 – 5.50 %), which was a contributor to the undesirable flavor, significantly correlated with the levels of soy protein substitution by oat flour and sensory scores, especially with the increase in overall liking. Moreover, higher proportion of oat flour in the protein bars significantly increased total phenolic content and antioxidant capacities determined by scavenging of DPPH and ABTS radicals and reducing of ferric iron. In conclusion, our research established the optimal ratio of soy protein to oat flour necessary for developing nutritious protein bars that exhibit significantly improved texture and flavor. The observed improvements in sensory and physicochemical properties suggest that incorporating oat flour is a strategy for enhancing baked products with similar requirements. The development of these bars aligns with global efforts to enhance food security through the use of sustainable, plant-derived alternatives.
Rakariyatham et al. (Fri,) studied this question.