Abstract: The effects of a high level (30%, m/m) of different cereal brans (wheat, triticale and oat) added to wheat flour on dough rheological properties, and gluten composition and secondary structure were studied. The results showed that addition of cereal bran, rich in dietary fiber, resulted in a remarkable increase of water-absorbing capacity and breakdown viscosity, a distinct decrease of setback viscosity and in general an increase of dough development time and stability time, which were dependent on cereal varieties. Moreover, an increase in gliadin and glutenin of 24.7%–73.0% and a reduction in disulfide bond content of 26.0%–35.5% were found. β-Sheet was the predominant secondary structure of gluten proteins, and addition of wheat and triticale brans led to the conversion of β-turn to β-sheet. The scanning electron microscopy showed that addition of cereal bran destroyed the compact and uniform microstructure of gluten. Together these findings indicated that bran addition could result in changes in gluten composition and secondary structure, leading to the deterioration of dough rheological properties and the final product quality.

Key words: thermomechanical property, gluten protein, disulfide bonds, secondary structure, microstructure