Endosperm

endosperm. (ehn'-do-sperm)

    The starch-containing sac of the barley grain. The endosperm constitutes 80–85 percent of the dry weight of the grain. Part of this starch serves as a food reserve for the growing embryo during the cytosis process while the remainder constitutes the bulk of the extract during the mashing. The sugars found in the endosperm include glucose, fructose, maltose, sucrose, and higher fructosans. Also called: starchy endosperm.