Optimization of wheat flour and purple sweet potato paste for texture, specific volume, and bread color using the mixture design method

Abstract Wheat flour is one of the important ingredients in bread processing because it contains gluten which greatly affects the character of the bread. In this research, wheat flour was substituted with purple sweet potato paste to reduce dependence on the use of wheat flour. Purple sweet potato has the potential for processing food products because of its nutritional content and very attractive natural purple color. This research uses the Optimal Custom Design Mixture Design Method which consists of two factors, namely wheat flour (40-90%) and purple sweet potato paste (10-40%) on 5 physical characteristic responses, namely texture, specific volume, color L, color a, and color b. The data were analyzed using expert design 13 with 8 formulations. The results show that the optimization of the wheat flour formulation 65.025% and purple sweet potato paste 34.975% is predicted to produce bread with a texture value of (texture analyzer) 2.945 N, specific volume 3.488 cm 3 /g, color L brightness level is 57.650%, color a is 3.410, and color b is 11.910 (manual method of color reader tool) with a desirability of 0.613.