L-Arabinose is a white crystalline powder, no odour, freely soluble in water, slightly soluble in alcohol, and not soluble in ether, methanol and acetone. It is also known as pectinose, pectin sugar, and gum sugar, and is a kind of aldopentose. L-Arabinose rarely exists in nature in the form of monosaccharide, usually combining with other monosaccharides, existing in pectin, hemicellulose, pectin acid, polysaccharide of bacteria and some glycoside in the form of heteropolysaccharide. It is high stable against acid and heat.