Enzymatic Hydrolysis of Skin Shavings for Preparation of Collagen Hydrolysates with Specified Molecular Weight Distribution

Collagen hydrolysates were extracted from tannery skin shavings through enzymatic hydrolysis by using protease 1398, protease 2709, Alcalase, papain, pepsin, protease 537 and trypsin, respectively. The hydrolytic degree and molecular weight distribution (MWD) of the hydrolysates were evaluated by the formaldehyde titration method, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), Tricine-SDS-PAGE and centrifugal ultrafiltration. It was found that the MWD of the as prepared collagen hydrolysates has a close correlation with the hydrolytic degree, and greatly depends on the enzyme employed. The low molecular weight (MW) collagen hydrolysates, with relatively high hydrolytic degree, were obtained by enzymatic hydrolysis using protease 1398, protease 2709, papain and Alcalase. More than 60% (mass ratio) of the fractions in these four hydrolysates were in the molecular weight range of <10kDa. The use of protease 537 produced medium-MW collagen hydrolysates where 40% of the fractions were of 10-30kDa. The high-MW collagen hydrolysates that include about 66% fractions with molecular weights higher than 30kDa were obtained by using pepsin, accompanied by the lowest hydrolytic degree. This research provides a potential approach for molecular weight and molecular weight distribution control of collagen hydrolysates by enzymatic hydrolysis of tannery skin wastes.