Enzymic analysis of the structure of oxidized potato starches.

The possibility to use enzymic methods for the analysis of the positions of carboxyl and carbonyl groups in sodium hypochlorite oxidized (HO) and hydrogen peroxide oxidized (PO) potato starches was investigated. The HO-starch, that contained more modified glucosyl residues, possessed a lower beta-amylolysis limit and all of the polymer components were resistant to complete hydrolysis as judged from gel-permeation chromatograms. In contrast, the PO-starch contained 24% of apparently unmodified, linear chains that were hydrolysed by beta-amylase. After debranching, approximately 30% of the chains in the HO-sample and approximately 20% in the PO-sample remained partly resistant to successive beta-amylolysis.