Oligosaccharides - Definition, Classification and Examples | Testbook.com

Table of Contents

• Defining Oligosaccharides
• Categories of Oligosaccharides
• A Closer Look at Various Oligosaccharides
  • The Raffinose Family
  • Exploring Fructooligosaccharides
  • Unveiling Galactooligosaccharides

Defining Oligosaccharides

Oligosaccharides are a type of carbohydrate composed of a small number of monosaccharides (2-10 units). These monosaccharides may vary, but the most commonly researched are fructooligosaccharides and galactooligosaccharides. Some oligosaccharides, such as maltotriose, are absorbed in the small intestine after being hydrolysed.

Categories of Oligosaccharides

Oligosaccharides are classified based on the number of sugar units they contain. The categories include:

Trisaccharides : Composed of three monosaccharides. An example is kestose, made up of glucose, fructose, and fructose.

Tetrasaccharides : Composed of four sugar units. An example is stachyose, made up of two units of galactose, one unit of glucose, and one unit of fructose.

Pentasaccharides : Composed of five monosaccharides. An example is verbascose, made up of three galactose units, one fructose unit, and one glucose unit.

Hexasaccharides : Composed of six sugar units.

And so on for Heptasaccharides, octasaccharides, etc.

A Closer Look at Various Oligosaccharides

The Raffinose Family

Raffinose, a trisaccharide with the formula C18H32O16, is made up of three sugar units – fructose, glucose, and galactose. When hydrolysed with the α-galactosidase enzyme, it produces D-galactose and sucrose. Raffinose is found in various plants such as beans, whole grains, and various vegetables.

Exploring Fructooligosaccharides

Fructooligosaccharides are derived from plants. They are also known as oligofructans and are considered storage saccharides. These short chains of fructose residues are common in a variety of plants. Examples include chicory root, Jerusalem artichoke, and garlic. They are often used in the food industry as sweeteners and to enhance texture and colour.

Unveiling Galactooligosaccharides

Galactooligosaccharides are composed of galactose molecules. An example is Human milk oligosaccharides (HMOs), which are found in breast milk and are derived from lactose. 2′-fucosyllactose, a trisaccharide composed of fucose, galactose, and glucose, makes up 30% of all HMOs.

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Learn more:

• Detailed Classification & Examples of Carbohydrates
• Deep Dive into Oligosaccharides