Impact of wheat bran dietary fiber on gluten and gluten-starch microstructure formation in dough

Visualization of the gluten network microstructure of dough is crucial to gain knowledge about the interactions of its various ingredients. In this study, various techniques, including mainly microscopy imaging, were applied to examine the effect of wheat bran dietary fiber (WBDF) on gluten (G) and gluten-starch (G+S) microstructure. The results revealed that doughs containing WBDF particles have a looser gluten structure and a larger number of large gas cells. This should be attributed to the thinning and breakage of protein fibrils caused by the WBDF, which lead to premature rupture of gas cells. In addition, light microscopy micrographs clearly showed that the WBDF particles settled around the gas cells and created a physical barrier, which might impose restrictions on gas cell expansion during proofing. These findings indicated impairment of the dough structure upon addition of the WBDF, implying the possible deterioration of the quality of wheat bran-fortified products.