Structure of (1-3)(1-4)-(beta)-D-Glucan in Waxy and Nonwaxy Barley.

The endosperm cell walls of barley are composed largely of a (1-3)(1-4)-(beta)-D-glucan commonly known simply as beta-Dglucan (Wood 2001). There has been much research into the characteristics of barley beta-glucan because of the influence of this polysaccharide on performance of barley in malting and subsequent brewing of beer, and in feed value, especially for young chicks (MacGregor and Fincher 1993). The potential for beta-glucan to develop high viscosity is a problem in these uses, but from the perspective of human nutrition, this characteristic may be an advantage. The glycemic response to oat (beta)-glucan is inversely related to (log)viscosity (Wood et al 1994a) and there is evidence to suggest that the lowering of serum cholesterol levels associated with oat and barley products (Lupton et al 1994; Wood and Beer 1998) is at least in part due to the betaglucan (Braaten et al 1994) and probably also its capacity to develop viscosity in the gastrointestinal tract (Haskell et al 1992).