Amylose and β-Glucan Content of New Waxy Barleys

Abstract

Amylose and â-Glucan Content of New Waxy BarleysStarch was isolated from four new waxy barleys and compared with normal and highamylose 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-2B 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 l max range of 550-600 nm. The water extractable and acid extractable b-glucan contents in the waxy barley cultivars were generally found to be higher than those in normal barley.

Hulless Barley – A Rediscovered Source for Functional Foods Phytochemical Profile and Soluble Dietary Fibre Content in Naked Barley Varieties and Their Antioxidant Properties

“…Generally, high-amylose and waxy hulless barleys tend to contain more β-glucan than zero-amylose and regular hulless barleys. More precisely, waxy barley cultivars possess higher levels of water and acid extractable β-glucans than regular barleys (Ajithkumar et al, 2005;Izydorczyk et al, 2000). Our results are consistent with previously published studies (Andersson et al, 2008;Gao et al, 2009).…”

“…Starch itself is composed of two types of glucose polymers namely the highly branched amylopectin and the linear amylose. According to the proportions of amylose and amylopectin barley can further be classified: normal naked barley contains 25 -30% amylose, waxy varieties less than 15% whereas high-amylose cultivars more than 35% amylose (Ajithkumar et al, 2005;Bhatty, 1986;1999). Among the waxy cultivars there are also zero-amylose waxy barleys that contain no amylose (Izydorczyk et al, 2000).…”

Barley Starch: Composition, Structure, Properties, and Modifications

“…It should also be stressed that the amylose content reported in Table can be much affected by the quantification method. Various methods for amylose content measurement are based on iodine‐binding amperometry, iodine‐binding spectrophotometry, iodine‐binding potentiometry, concanavalin A‐precipitation, and gel‐permeation chromatography (GPC; high pressure and low pressure) of whole/debranched starch (Ajithkumar and others ; Matsuki and others ; Regina and others ; Yangcheng and others ). Different measuring methods may give different results to the same starch sample.…”

Tempe Fermentation of Whole Grain Barley Increased Human Iron Absorption and In Vitro Iron Availability

“…According to the study by Brune et al [28], phytate-P content corresponding to those of the TM and BBM meals were expected to result in ~13% and ~7.5% iron absorption respectively. The low iron absorption may be explained by the fact that barley kernels in both TM and BBM were largely intact, and of a high amylose/ß-glucan variety [34], factors which have been suggested to induce a slow digestion and a low glycemic response [35,48,49]. Consequently, the release of iron from the food matrix might be restrained.…”

“…The high ß-glucan (6.3%) and high amylose (40.7%) variety barley, cv. Karmosé [34], was obtained from Svalöf Weibull AB, (Svalöv, Sweden). This variety was chosen since the barley tempe was simultaneously optimised to induce low glycemic response, examined in a separate study [35].…”