TOTAL, WATER-SOLUBLE AND ACID-SOLUBLE ARABINOXYLANS IN WESTERN CANADIAN BARLEYS

Non-starch polysaccharides, such as beta-glucan and arabinoxylan, are often implicated as a cause of the poor feeding value of barley for po ultry. Levels of arabinoxylan in Canadian barley types, though, have n ot been thoroughly investigated. Total, water-extract and acid-extract arabinoxylan levels were determined for six-rowed (covered), two-rowe d (covered) and hulless (both six- and two-rowed) barley (Hordeum vulg are) cultivars and genotypes grown in the 1991 Western Canadian Parley Cooperative Program. Analyses were performed using a dichromatic modi fication of the orcinol method. The six-rowed barley types contained s ignificantly greater total, water-extract and acid-extract arabinoxyla n concentrations than hulless or two-rowed types (P < 0.05). In hulles s barley, total (P < 0.01), water-extract (P < 0.01), and acid-extract (P > 0.05) levels of arabinoxylan were, respectively, less than, grea ter than and similar to levels of arabinoxylan in samples of two-rowed barley. Environment had a significant effect on levels of water-extra ct (P < 0.01) and acid-extract(P < 0.05) arabinoxylan. Genetic differe nces affected the arabinoxylan content of cultivars and genotypes with in each of the barley types (P < 0.05). Levels of acid-extract arabino xylan were positively correlated with the viscosities of acid extracts of the barleys (P < 0.001).