Elucidation of morphological characteristics, crystallinity, and molecular structures of native and enzyme modified cereal brans.

Abstract

Bran is a nutritious outermost layer of the cereal grain that is removed during milling to curtail the technical problems in end-products. Modification techniques such as enzyme treatments might be an effective way to alter bran morphology and end-use quality. In this study, bran from six cereals (wheat, barley, oat, maize, millet, and sorghum) were enzymatically modified (cellulase and xylanase), and evaluated for morphological properties through scanning electron microscopy, crystallinity through x-ray diffraction and molecular structures through FTIR spectroscopy. Scanning electron microscopy revealed that enzyme modifications caused breakage in bran fibers by hydrolyzing non-starch polysaccharides. X-ray diffraction exhibited that crystallinity of the structures was increased after modifications as enzymes hydrolyzed amorphous regions of cellulose and hemicellulose in bran matrix. Molecular structures studied by FTIR spectroscopy demonstrated absorption in wavelength ranges of 900-3400cm-1 associated to carbohydrates, oligosaccharides, proteins, and non-starch polysaccharides. PRACTICAL APPLICATIONS: Cereal bran creates technical problems for food processors and bakers in terms of grittiness leading to the unacceptability of the product. The bran can be modified using different approaches, such as enzyme modifications. This research will be helpful for the food scientists & researchers and bakers for making choices for preferred method of bran modification. This will also be helpful for cereal scientists for the understanding of structural properties of bran layers.