Xylose

Xylose is a monosaccharide, specifically a pentose sugar, meaning it contains five carbon atoms. It is also known as wood sugar, due to its abundance in woody plant material.

Xylose is a white, crystalline solid that is soluble in water. It has a sweet taste, though not as sweet as sucrose (table sugar). In its pyranose form, it exists predominantly as β-D-xylopyranose in solution.

Occurrence:

Xylose is a major component of hemicellulose, a complex carbohydrate found in plant cell walls. It is present in various agricultural residues, such as corn cobs, straw, and bagasse (sugarcane waste). It is less common as a free sugar.

Production:

Xylose is typically produced by hydrolysis of hemicellulose-rich materials. This process breaks down the hemicellulose into its constituent sugars, including xylose. The xylose can then be purified and crystallized.

Uses:

• Food Industry: Xylose is used as a low-calorie sweetener and as a browning agent in some foods.

• Chemical Industry: Xylose can be converted into xylitol, a sugar alcohol used as a sugar substitute. It can also be fermented to produce ethanol and other chemicals.

• Research: Xylose is used in research as a model compound for studying carbohydrate metabolism and fermentation.

Metabolism:

Xylose is metabolized differently than glucose. In mammals, xylose is primarily metabolized through the uronic acid pathway. It is poorly absorbed from the gut, which contributes to its lower caloric value. Some individuals can exhibit xylose intolerance, though this is relatively rare.