Structural properties of gluten modified by ascorbic acid and transglutaminase
The effect of Transglutaminase (TG) and Ascorbic acid (AA) on physicochemical properties of gluten was studied. The results showed that TG increased gluten yield, storage modulus and particle size distribution by forming G-L bond in protein structure. TG causes the changes in the three-dimensional structure of gluten by forming (G-L) bond in the protein chains and partly preventing disulfide bond formation. But in the high concentration of enzyme, by reducing the ratio of lysine to glutamine, TG catalyses the deamidation of glutamine residues and thus the K′, gluten yield and particle size decrease significantly. The rheological behavior of GMP gel was changed and the gluten extensibility increased. AA leads to improve the aggregation of gluten and increases the particle size distribution. The results showed that AA lead to increase the disulfide bond formation and the strength of gluten network. Adding AA reduced delta value and increased G’ compared to the control.