DOI: 10.1094/CFW-51-0062 |
Cell Walls of Cereal Grains
B. A. Stone. La Trobe University, Melbourne, Australia. Cereal Foods World 51(2):62-65.
Cell walls have important impacts on the end-use characteristics of cereal grains in milling, bread- and pasta-making, malting, and brewing, and their components contribute dietary fiber and play a variety of roles in disease prevention. Their structure and composition relates directly to the biological functions of the grain tissues. The composition of the aleurone and endosperm cell walls is dominated by the noncellulosic polysaccharides arabinoxylans and (1→3,1→4)-beta-glucans, while cellulose and proteins are also present. The organization of these components in the cell walls is largely directed by noncovalent interactions with one another; however, covalent associations through hydroxycinnamic acid bridges do occur, especially between lignins and arabinoxylans, as seen in the cell walls of vegetative and outer grain tissues. In the aleurone cell walls there are putative associations between arabinoxylans and protein. The development of walls during the cellularization stages of endosperm formation follows a pattern that differs from normal wall formation, and the sequence of deposition provides information on the action of the synthases. Possibilities exist for the manipulation of cell wall polysaccharide composition to enhance end-use properties through marker-assisted selection, mutation, postharvest chemical or enzymatic treatment, and, in the future, generation of transgenic cereals.