Effects of roasting on barley β-glucan, thermal, textural and pasting properties

Different hulled barley cultivars were subjected to roasting in hot sand (280 degrees C) and the effects on beta-glucan extractability, physico-chemical, thermal and pasting properties were studied. The grain puffed upon roasting and grain hardness and colour difference Delta E were significantly lowered. The roasted barley flour had significantly higher water absorption and water solubility index. The cultivars DWR-28, RD-2503 and PL-172 had the highest total beta-glucan content (up to 5.47%). Roasting brought about a decrease in the soluble beta-glucan content in all the cultivars and this decrease ranged from 4.9 to 25.3%. The beta-glucan extractability was not affected by the roasting process but roasting lowered the ratio of soluble to insoluble beta-glucan content by 8.1-41.9%. Roasting significantly affected the pasting and thermal properties of the flours, together with an increase in the cooked starch content that ranged from 28.8 to 43.1%. (C) 2010 Elsevier Ltd. All rights reserved.