Cellulose and chitin are examples of structural polysaccharides. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch). The extracellular matrix contains proteins, long-chain polysaccharides and lipids. Shorter polysaccharides, with 3 - 10 monomers, are called oligosaccharides. They include&colon; alkamides, caffeic acid derivatives, polysaccharides, and glycoproteins. The hydrolysis of polysaccharides to soluble sugars can be recognized as saccharification. Food thickeners frequently are based on either polysaccharides (starches, vegetable gums, and pectin), or proteins. These polymers are usually composed of polysaccharides and sometimes protein. Glycosaminoglycans are long, unbranched polysaccharides (relatively complex carbohydrates) consisting of repeating disaccharide units. Enzymatic breakdown and hydrolysis of storage polysaccharides occurs during ripening. Glucosamine is part of the structure of the polysaccharides, chitosan, and chitin. Most true fungi have a cell wall consisting largely of chitin and other polysaccharides. The theca is a secreted covering predominately composed of cellulose or other polysaccharides. Bacterial fermentation of undigested polysaccharides produces these. NMR analysis revealed that the foam contained mainly polysaccharides, sucrose and protein.