Stachyose

A tetrasaccharide carbohydrate found in numerous vegetables

Chemical structure of stachyose

Stachyose is a tetrasaccharide carbohydrate consisting of two galactose units, one glucose unit, and one fructose unit. It is commonly found in various vegetables, including beans, peas, and other legumes. Stachyose is part of the raffinose family of oligosaccharides (RFOs), which are known for their role in plant metabolism and their impact on human digestion.

Structure and Composition

Stachyose is composed of four monosaccharide units linked together. The structure can be described as a galactose-galactose-glucose-fructose sequence. The chemical formula for stachyose is C₂₄H₄₂O₂₁. The presence of multiple hydroxyl groups makes stachyose highly soluble in water.

Occurrence in Nature

Stachyose is naturally found in a variety of plant sources, particularly in the seeds of leguminous plants. It is a significant component of the raffinose family of oligosaccharides, which also includes raffinose and verbascose. These oligosaccharides are not digestible by humans due to the lack of the enzyme alpha-galactosidase, leading to their fermentation by gut microbiota and the production of gas.

Role in Plants

In plants, stachyose serves as a transport carbohydrate, facilitating the movement of sugars from the photosynthetic tissues to other parts of the plant. It is also involved in the storage of energy and plays a role in the plant's response to environmental stress.

Impact on Human Digestion

Stachyose, like other oligosaccharides in the raffinose family, is not digested in the small intestine due to the absence of the enzyme alpha-galactosidase. Instead, it passes into the large intestine, where it is fermented by bacteria, producing gases such as hydrogen, methane, and carbon dioxide. This can lead to flatulence and discomfort in some individuals.

Uses and Applications

Stachyose is used in the food industry as a prebiotic, promoting the growth of beneficial gut bacteria. It is also studied for its potential health benefits, including its role in improving gut health and immune function.

Related pages

• Raffinose family of oligosaccharides
• Prebiotics
• Flatulence
• Legumes