Molecular Weight Distribution in Starch Solutions when Hydrolised with alpha‐Amylase and when Oxidised with Sodium Hypochlorite

The time course for hydrolysis of starch with α‐amylase and oxidation of starch with Na‐hypochlorite was studied with the aid of gel chromatography. It was found that the initial steps in the hydrolysis can be described as a consecutive reaction in which the fractions Mw > 5 · 105, 5 · 105 > Mw > 1 · 105 and Mw < 1 · 105 are contained. The reaction in the course of decomposition with α‐amylase is one of the first order, while decomposition by means of hypochlorite is a second order reaction. There are considerable differences in the changes in molecular weight distribution between the two methods. Hydrolysis with α‐amylase gives a solution with a symmetrical molecular weight distribution whereas hypochlorite oxidation obviously causes splitting of some of the starch molecules, which results in solutions with two molecular weight maxima.