Amylases are not the only carbohydrases useful in bakery products. Pentosanases also can be added to improve quality. Both wheat and rye flour contain pentosans. These non-starch polysaccharides are highly hydrophilic and contribute significantly to the water absorption properties of a dough. In wheat flour-based products, pentosans also interfere with volume development. Adding pentosanase to a wheat flour-based product can improve product volume by hydrolyzing the pentosans present. At the same time, though, hydrolyzed pentosan will release water, making the dough very slack. When using pentosanase, the water absorption of the dough must be adjusted to compensate. If the dough is too slack, not only will it be difficult to machine, but the volume-building benefits of the pentosanase will not occur. In rye bread, the pentosans in the rye flour are critical to building structure since rye flour's gluten content isn't sufficient. If pentosan content is too high, though, it will compete for water with the starch and prevent it from swelling and gelatinizing properly. Pentosanase will help control the pentosan content so there is enough to build structure, but not so much as to interfere with the starch functionality. Pentosanases that hydrolyze cellulose also are available. These may be added to high-fiber bakery products to help improve their eating qualities by breaking up the long cellulose chains that contribute to gritty mouthfeel.