Xylose

Xylose is a monosaccharide of the aldopentose type, which means it contains five carbon atoms and includes an aldehyde functional group. It is a naturally occurring sugar found in the hemicellulose of plant cell walls and is a significant component of wood and biomass. Xylose is classified as a reducing sugar and is often used in the production of xylitol, a sugar substitute.

Structure and Properties

Xylose has the chemical formula C5H10O5. It exists in two forms: D-xylose and L-xylose, with D-xylose being the more common isomer found in nature. The structure of D-xylose can be represented as:

Xylose is a crystalline solid that is soluble in water and has a sweet taste. It is less sweet than glucose and sucrose.

Occurrence

Xylose is a major component of hemicellulose, which is a complex carbohydrate found in the cell walls of plants. It is particularly abundant in hardwoods, straw, and corncobs. The hydrolysis of hemicellulose releases xylose, which can then be fermented to produce biofuels and other chemicals.

Metabolism

In humans, xylose is absorbed in the small intestine and is metabolized by the liver. It is not as readily utilized by the body as glucose, and a significant portion of ingested xylose is excreted in the urine. Xylose is used in medical tests to assess the absorptive capacity of the small intestine.

Uses

Xylose is used in various industrial applications, including:

• The production of xylitol, a sugar alcohol used as a sweetener in sugar-free products.
• As a precursor for the production of furfural, a chemical used in the manufacture of resins and solvents.
• In the food industry as a sweetener and flavor enhancer.

Health Effects

Xylose is generally considered safe for consumption. It has a low glycemic index, making it suitable for people with diabetes. However, excessive consumption may lead to gastrointestinal discomfort.

Related Pages

• Monosaccharide
• Hemicellulose
• Xylitol
• Furfural
• Glucose
• Sucrose