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Effect of extrusion cooking on the primary structure and water solubility of beta-glucans from regular and
waxy barley. THAVA VASANTHAN and Jiang Gaosong. University of Alberta.
Water-soluble beta-glucan from native and extrusion cooked barley
flours of two barley cultivars, Candle (a waxy starch barley) and Phoenix (a regular starch barley), was
isolated and purified. The purity of beta-glucan samples ranged from 85 to 93% (w/w, dry weight basis) for
Candle and 77 to 86% (w/w, dry weight basis) for Phoenix. The water solubility of beta-glucan (at room
temperature, 25°C in the native and extruded flours (primary solubility) was different from that of the
purified beta-glucan samples (secondary solubility). The solubility of beta-glucan in the native and extruded
Candle flour was substantially higher than that of Phoenix. For both varieties, beta-glucan in the extruded
flours had solubility (primary solubility) values higher than their native counterparts. The solubility of
beta-glucan in the purified beta-glucan samples differed depending upon the barley cultivar and the extrusion
conditions employed. The glycosidic linkage profiles of purified beta-glucan from native and extruded
barley flours were determined in order to understand the changes in the primary structure of beta-glucan and
the effect of extrusion on beta-glucan structure-solubility relationship.
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