Barley Hulls and Straw Constituents and Emulsifying Properties of Their Hemicelluloses

Barley hulls (husks) are potential by-products of barley ethanol production. Barley straw is an abundant biomass in the regions producing barley for malting, feeds, and fuel ethanol. Both barley hulls and straw contain valuable hemicelluloses (arabinoxylans) and other useful carbohydrate and non-carbohydrate components. To characterize all the components of barley hulls and straw, they were treated with hot water to obtain water extractable materials and with α-amylase to remove starch. The water soluble hemicelluloses were isolated from hot water-extracted and de-starched barley hulls/straw by an alkaline extraction followed by ethanol precipitation. The oligosaccharides and acid insoluble lignin present in the supernatant after arabinoxylan precipitation were also obtained and partially characterized. The structural and the emulsifying properties of these hemicelluloses were studied.