To obtain a nutritively excellent food having a beautiful red appearance by adding a Karkade rich in minerals such as iron, magnesium and calcium and exhibiting a stable red color as a doughimproving agent to a dough for breads or cakes.

Karkade is singly added as a dough-improving agent to a dough in such an amount as giving the pH of the dough suitable for various kinds of breads or cakes, or added together with an alkalicontrolling agent to the dough to control the dough in a pH range suitable for the various kinds of the breads or the cakes. For the breads, the Karukade is preferably added to wheat flour in an amount of 0.1-10wt.%.