Hydrated gluten modified by a transglutaminase

A microbial transglutaminase (TGase), was used to add covalent bonds in glutens obtained from three near-isogenic lines differing in their high Mr glutenin subunits content. After TGase treatment, 29-45% of the total proteins remained soluble instead of 70-90% for the untreated glutens, due to the formation of large insoluble polymers as shown by SDS-PAGE. The enzymatic treatment was effective in making gels with high elastic modulus from all tested glutens: G' was increased from 10 to 50 times and G from 2 to 4 times. The dynamic moduli of the reaction products were less frequency dependent than those of the non treated gluten. Despite the low lysine content of the gluten, the formation of permanent connections reinforced the network structure and modified the viscoelasticity properties of gluten.