GELATION OF WAXY BARLEY STARCH HYDROLYSATES

The alpha-amylolysis of gelatinized waxy barley starch and the gelatio n of the hydrolysates was studied. The progress of the hydrolysis was monitored with gel permeation and ion exchange chromatography. Initial attack occurred mainly between the clusters, without significant hydr olysis of the external chains. The stiffness of 20% gels prepared from the polymeric products decreased with increasing hydrolysis of the am ylopectin. A linear relationship between the shear modulus and the ori ginal high-molecular weight amylopectin content was observed. Although the branched degradation products of amylopectin (average DP <6 x 10( 4)) were not involved in network formation, they retained their abilit y to recrystallize as analysed by differential scanning colorimetry. F or more extensively hydrolysed produces (average DP <5000) no recrysta llization or gel formation was observed under the condiions tested. In formation on the gel structure was obtained with acid hydrolysis and i on exchange chromatography. The structure of the acid-resistant gel re sidues was complicated, showing a five-peak distribution when analysed with ion exchange chromatography. No differences between the original and hydrolysate gels was observed. The gel residues were resistant to isoamylase. (C) 1997 Academic Press Limited.