Stachyose

Stachyose is a tetrasaccharide consisting of two α-D-galactose units, one α-D-glucose unit, and one β-D-fructose unit sequentially linked as gal(α1→6)gal(α1→6)glc(α1→2)fru. It is naturally found in various vegetables, legumes, and whole grains, making it a significant component of the human diet in many cultures. Stachyose is particularly abundant in plants like soybeans, legumes, and other beans, where it functions as both a source of stored energy and a solute contributing to the regulation of osmotic pressure.

Structure and Properties

Stachyose is part of the raffinose family oligosaccharides (RFOs), which are oligosaccharides built up from sucrose by sequential addition of galactose units. Due to its structure, stachyose is not digestible by humans directly because the human gastrointestinal tract lacks the enzyme α-galactosidase, which is necessary to break down the α-1,6-glycosidic linkages between galactose molecules.

Biological Role and Dietary Significance

In plants, stachyose plays a crucial role in carbon transport and storage. In the human diet, it reaches the colon intact and is fermented by the resident microflora. This fermentation process can produce gas, leading to the characteristic bloating and discomfort associated with consuming large amounts of legumes and other stachyose-rich foods.

The presence of stachyose in the diet is also linked to various health benefits. It acts as a prebiotic, promoting the growth of beneficial bacteria in the gut such as Bifidobacteria and Lactobacilli. These beneficial effects contribute to improved gut health and may enhance immune function.

Commercial Use

Stachyose is extracted from various sources for use in the food and pharmaceutical industries. It is used as a functional ingredient in foods, given its prebiotic properties, and is also explored for its potential in managing blood sugar levels and improving mineral absorption.

See Also

• Oligosaccharide
• Prebiotic (nutrition)
• Soybean
• Legume