Effect of roselle and purple rice powder on baking quality and aroma characteristic of bread

Abstract

The effects of different dosages of roselle flour (0 %, 4 %, and 8 %) and purple rice flour (5 %, 10 %, and 15 %) on the properties of the dough, the quality of the bread, the phenolic compounds contained, the anthocyanin content and the aroma profile were investigated by adding roselle flour and purple rice flour to the wheat flour. The results showed that the addition of purple rice flour elevated the G′ and G″ of the dough and improved the viscoelasticity of the bread. The addition of roselle flour disrupted the gluten network structure in the bread, resulting in an increase in chewiness and hardness, but within acceptable limits. The color of the bread also changed significantly. In addition, increased polyphenol content in the bread, roselle flour, and purple rice flour significantly (p < 0.05) increased the aroma profile of bread, giving it a richer odor. In particular, the presence of more acids, alkanes and heterocyclic compounds associated with fruity flavors also adds a distinctive burnt and ‘roasted’ note. Therefore, the addition of moderate amounts of roselle flour and purple rice flour was beneficial in improving the baking quality of bread, especially positively affecting the flavor.