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Abstract An improved method for the determination of starch by sequential hydrolysis with thermostable bacterial α‐amylase and fungal amyloglucosidase is described. Glucose was determined colorimetrically by a glucose oxidase‐peroxidase‐chromogen system at pH 7. Native normal and waxy starches, and distarch phosphate, gave quantitative yields of glucose with a high degree of precision (coefficient of variation less than 1%). Acetylated distarch phosphate, high‐amylose starch and retrograded amylose were initially treated with 1M NaOH for 30 min, then neutralised and analysed successfully as normal starch. Oxidised starch did not give a quantitative yield of glucose because of the presence of dicarboxylic groups in the polymer. For samples containing normal and waxy starch the analysis was carried out in about 4 h. The method was applied to a range of starch‐containing foodstuffs and the results are reported.
John Karkalas (Tue,) studied this question.