Preparation of chitooligosaccharides with degree of polymerization higher than 6 by acid or enzymatic degradation of chitosan

摘要

Chitosan was depolymerized either by HC1 hydrolysis or enzymatic degradation with a commercial preparation Pectinex Ultra Spl.The chitooligosaccharides released by both methods were selectively precipitated in methanol solutions and characterized using MALDI-TOF mass spectrometry.Differences between the two methods were detected and concerned the degrees of polymerization of the fragments produced and their acetylation.The enzymatic method yielded shorter fragments with a higher proportion of fully deacetylated chitooligomers.Conversely,acid hydrolysis of the starting chitosan resulted in fragments with degrees of polymerization up to sixteen and more monoacetylated residues than with the enzymatic procedure.