Effect of Microbial Transglutaminase on Protein Electrophoretic Pattern and Solubility of Wheat Flour and Hull-Less Barley Flour Blends

Background: Barley flour does not contain gluten, so preparation of high-quality bread is not easy. Thus, the incorporation of microbial transglutaminase (MTG) can be attributed as one of the possible strategies to provide crosslinks between wheat and barley proteins to prepare a similar structure to the desired network of gluten. Methods: The MTG, at different levels (0.5, 1, 1.5, and 2%) was added to wheat and hull-less barley in order to evaluate the solubility of available proteins and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) patterns of (20, 35, 50%) dough proteins as well as their fractions by using an electrophoretic system. Also, to enhance the extent of cross-linking in protein matrix by incorporation of MTG, soy protein isolate (SPI) was used (1% MTG+3% SPI, 1.5% MTG+3% SPI). Results: Interactions between wheat and hull-less barley proteins were intensified due to the formation of catalyzed intermolecular covalent bonds by transglutaminase. According to SDS-PAGE results with increment in the levels of MTG, a progressive decrease in the intensity of the bands corresponding to the molecular weight of around 66 KDa was observed. Also by the addition of MTG, the amounts of the soluble proteins (albumin and glubolin) were significantly decreased and the concentrations of insoluble proteins (glutenin and gliadins) were increased. Conclusion: The addition of hull-less barley flour to wheat flour not only provides protein-enriched dough with better amino acid balance but also has influences on dough properties.