Submitted to: International Journal of Agricultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2011
Publication Date: 5/21/2011
Citation: Xu, J., Mohamed, A., Qureshi, N. 2011. The viscoelastic properties of the protein-rich materials from the fermented hard wheat, soft wheat and barley flours. International Journal of Agricultural Research. 6(4):347-357. Interpretive Summary: Biofuels are attractive to scientists not only because they can replace gas and diesel petroleum products, but also because they can prevent further increase of carbon dioxide emissions. Ethanol is widely used, however, butanol has some advantages over ethanol such as higher energy content, better blending ability, lower volatility, ability to be used in conventional engines without modifying the engines, and lower water absorption. Therefore, it is expected that more and more research on utilization of bio-butanol will be launched. Fermentation of cereal grains to make butanol and ethanol produces a protein-rich material after the alcohol is removed. It is very important for the commercial success of these processes to optimally utilize the production leftovers. Since most varieties of wheat and barley contain more proteins than the corn used in the alcohol industry, the fermentation of wheat and barley will create even more protein-rich leftover materials and the wise use of these residues becomes even more crucial for commercial success. This work determined the effect of the butanol production fermentation on the rheological properties of the residue remaining after fermentation of wheat and barley flours. We found that the protein-rich materials produced from the fermentation of wheat and barley flours exhibited viscoelastic behaviors and could have many potential utilizations in both food and non-food industries.
Technical Abstract: The linear and non-linear rheological properties of the suspensions for the hard red spring wheat (HRS) flour, soft wheat (Pastry) flour, barley flour, as well as the remain residues of HRS flour, Pastry flour, and barley flour after fermentation were investigated. The linear and non-linear rheological properties of the suspensions for vital wheat gluten and barley protein were also investigated and compared with the results for suspensions of residues from fermented HRS (FHRS), fermented Pastry flour (FP), and fermented barely flour (FB) respectively. The linear viscoelastic properties for all the materials in this study exhibited viscoelastic solid behaviors. While the non-linear rheological properties of the suspensions for all measured samples displayed shear-thinning behaviors, which can be well described by a power law constitutive model. Both linear and non-linear rheological properties for the FHRS suspension were similar to those for the vital wheat gluten suspension, and much stronger than those for the HRS suspension. The linear and non-linear viscoelastic properties for FP were stronger than those for Pastry flour suspension, but weaker than those for the wheat gluten suspension. For barley, both linear and non-linear rheological properties for FB and barley protein suspensions were close to each other,and stronger than those for un-fermented barley flour suspension. According to this study, it is highly expected that the FHRS and FB will be utilized as alternative materials for vital wheat gluten and barley protein respectively.