Amylose and β-glucan content of new waxy barleys

Starch was isolated from four new waxy barleys and compared with normal and high-amylose barley starch. The waxy barley samples were selected lines from crosses of Swedish hulled and naked barley cultivars with the cultivar Azhul as donor of the waxy gene. The starches from the waxy barley samples were found to contain 0.7-2.6% amylose when determined iodimetrically by amperometric titration and 0.0-0.9% when determined by size exclusion chromatography after debranching. However, Sepharose CL-213 elution profiles of the starches detected by iodine staining showed that all four waxy samples were free from detectable amounts of amylose. The amylopectin starches were found to contain a small polysaccharide fraction with molecular size smaller than amylopectin, with an iodine staining lambda(max) range of 550-600 nm. The water extractable and acid extractable beta-glucan contents in the waxy barley cultivars were generally found to be higher than those in normal barley.