This study evaluated the color, DPPH radical activity, and sensory characteristics of nutritional bars supplemented with varying concentrations (0, 2.5, 5, and 7.5%) of freeze-dried Natto. An inconsistent pattern was observed for the L value, whereas both a and b values increased significantly up to 5% addition of freeze-dried Natto. The DPPH free radical scavenging activity of nutritional bars supplemented with 0, 2.5, 5, and 7.5% freeze-dried Natto were determined to be 59.54, 59.70, 44.85, and 55.07%, respectively. The appearance, color, taste, texture, and overall preference of nutritional bars supplemented with freeze-dried Natto showed significant differences between the samples. The overall preference of the nutrient bar was highest at 6.08 points, determined for the 2.5% Natto supplemented bar. The quality characteristics of the 2.5% added samples exhibited significantly higher values as compared to the controls, thereby indicating the potential of development in health-functional cereal bars.

The quality characteristics, total phenolic content, anthocyanin content, and DPPH radical scavenging activity of rice nutritional bar with added powder of aronia byproducts were investigated in this study. The rice nutritional bar was prepared by adding aronia byproducts powder at concentrations of 0%, 2%, 4%, and 6%. The pH of the rice nutritional bar batter was lowered for the control and 2% aronia byproducts powder was added. The moisture content, baking loss rate, leavening rate and specific volume of the rice nutritional bar decreased with as the aronia byproducts powder content increased. In relation to measurements of the colors of the rice nutritional bar crust and crumbs, as the content of aronia byproducts powder increased, the L and b values decreased while the a value increased. From texture analysis, the hardness and chewiness increased according to the level of added aronia byproducts powder, but the springiness and cohesiveness decreased. The total phenolic content, anthocyanin content, and DPPH radical scavenging activity showed the highest values in the rice bar with 6% aronia byproducts powder added. According to a sensory evaluation, overall preference was highest for the rice bar with 4% added aronia byproducts powder, whereas the color and taste was rated higher for the rice bar added with 4% and 6% aronia byproducts powder.