In this study, Sulgidduk samples were prepared with substitutions of 1, 2, 3, and 4% tomato powder, along with a control, and were then analyzed for quality characteristics such as moisture content, water activity, color, textural characteristics, and sensory qualities, in order to determine the optimal ratio of tomato powder in the formulation. According to the results, moisture content and water activity were not significantly different among the Sulgidduk samples. In terms of color, as the level of tomato powder content increased, lightness decreased, while the a-value (+redness/-greenness), and yellowness increased. For the textural characteristics, the samples showed significant differences for hardness, adhesiveness, and gumminess, while fracturability was not significantly different. In addition, the samples containing tomato powder presented significantly higher springiness, cohesiveness(except the 1% substitution level), chewiness, and resilience than the control group. In the sensory evaluation, the control group had significantly higher scores for color and flavor as compared to the tomato powder samples. Furthermore, flavor and overall acceptability decreased, while tomato flavor, sourness, and off-flavor increased with increasing tomato powder content. Sweetness and after-taste were not significantly different among the samples. In conclusion, the results indicate that substituting 2${sim}$3% tomato powder in Sulgidduk is optimal for quality, and provides a product with reasonably high overall acceptability.