Enzymatic hydrolysis of wheat gluten by proteases and properties of the resulting hydrolysates

The insolubility of gluten in aqueous solutions is one of the major limitations for its more extensive use in food processing. Wheat gluten was enzymatically hydrolyzed by several commercially available proteases (Alcalase 2.4L, PTN 6.0S, Pepsin, Pancreatin, Neutrase and Protamex™) with protein recovery of 81.3%, 42.5%, 53.3%, 61.6%, 46.3% and 43.8%, respectively. The hydrolytic efficiency of these proteases on wheat gluten was also compared. Alcalase served best for the preparation of wheat gluten hydrolysates with the maximum degree of hydrolysis (DH) 15.8%. Subsequently, the solubility of wheat gluten hydrolysates (WGHs) obtained with those enzymes was comparably evaluated. The products had excellent solubility (>60%) over a pH range of 2–12. The molecular weight distribution of WGHs was further determined by SDS-PAGE and size exclusion chromatography on Sephadex G-15. The results showed that with the increasing of DH values, there occurred a large amount of smaller polypeptides.