Oat Straw Extract from oat's (Avena sativa) endosperm cell walls. make to pulverization,use water to extract,concentrate and spray drying all in GMP workshop.NON-irradiation,GMO-free.Include β-glucan. It is a viscous polysaccharide made up of units of the monosaccharide D-glucose . Oat beta-glucan is composed of mixed-linkage polysaccharides. This means the bonds between the D-glucose or D-glucopyranosyl units are either beta-1, 3 linkages or beta-1, 4 linkages. This type of beta-glucan is also referred to as a mixed-linkage (13), (14)-beta-D-glucan. The (13)-linkages break up the uniform structure of the beta-D-glucan molecule and make it soluble and flexible.