Effect of microbial transglutaminase on the protein fractions of rice, pea and their blends

BACKGROUND: Transglutaminase (TG) is a transferase that has been used for crosslinking proteins. In general, those interactions are promoted within proteins of the same nature, and very few studies have been conducted for creating new bonds between proteins from different sources catalysed by TG. The effect of TG on the protein fractions of rice flour, pea protein isolate and their blends was studied by using different electrophoretic analyses (simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and multistaking SDS-PAGE under reducing and non-reducing conditions). RESULTS: TG induced the disappearance of numerous protein bands as a consequence of the formation of large protein polymers, linked by isopeptidic and disulfide bonds, with reduced solubility. The main protein fractions involved in those interactions were the albumins and globulins, from the pea protein isolate, and the rice flour; and the glutelins were also crosslinked. CONCLUSION: Composite flours containing the rice flour and the pea protein isolate are proposed for obtaining a protein-enriched dough with better amino acid balance. Also a protein network formed of protein aggregates of high molecular weight can be created in the presence of transglutaminase. (c) 2007 Society of Chemical Industry.