Milling Performance of North European Hull-less Barleys and Characterization of Resultant Millstreams.

Four hull-less barley samples were milled on a Bühler MLU 202 laboratory mill and individual and combined milling fractions were characterized. The best milling performance was obtained when the samples were conditioned to 14.3% moisture. Yields were 37-48% for straight-run flour, 47-56% for shorts, and 5-8% for bran. The (beta)-glucan contents of the straight-run white flours were 1.6-2.1%, of which (approximately) 49% was water-extractable. The arabinoxylan contents were 1.2-1.5%, of which (approximately) 17% was water-extractable. Shorts and bran fractions contained more (beta)glucan (4.2-5.8% and 3.0-4.7%, respectively) and arabinoxylan (6.1-7.7% and 8.1-11.8%, respectively) than the white flours. For those fractions, beta-glucan extractability was high (58.5 and 52.3%, respectively), whereas arabinoxylan extractability was very low ((approximately) 6.5 and 2.0%, respectively). The straight-run white flours had low alpha-amylase, beta-glucanase, and endoxylanase activities. The highest (alpha)-amylase activity was found in the shorts fractions and the highest betaglucanase and endoxylanase activities were generally found in the bran fractions. Endoxylanase inhibitor activities were low in the white flours and highest in the shorts fractions. High flavanoid, tocopherol, and tocotrienol contents were found in bran and shorts fractions