Structural properties of gluten modified by ascorbic acid and transglutaminase

Abstract

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