Carbohydrates are organic compounds composed of carbon (C), hydrogen (H), and oxygen (O), typically following the general formula (CH₂O)â‚™, where 'n' is the number of carbon atoms in the molecule. This formula reflects a ratio of hydrogen to oxygen atoms of 2:1, similar to that in water (H₂O). For example, glucose, a common monosaccharide, has the molecular formula C₆H₁₂O₆, fitting the (CH₂O)â‚™ pattern with n=6. However, not all carbohydrates conform strictly to this formula; some derivatives may have different ratios due to modifications in their structure

 They are a primary source of energy for the body and play crucial roles in various biological processes. Carbohydrates are classified based on their chemical structure and complexity into the following types:

1. Monosaccharides

Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are the building blocks for more complex carbohydrates. Common monosaccharides include:

  • Glucose: A primary energy source for cells.
  • Fructose: Found in fruits and honey; known for its sweet taste.
  • Galactose: Typically linked with glucose to form lactose, the sugar in milk.

Classification based on the number of carbon atoms:

Trioses (C₃H₆O₃) → Glyceraldehyde, Dihydroxyacetone

Tetroses (C₄H₈O₄) → Erythrose

Pentoses (C₅H₁₀O₅) → Ribose, Xylose

Hexoses (C₆H₁₂O₆) → Glucose, Fructose, Galactose


2. Disaccharides (Double sugar)

Formed by the condensation of two monosaccharides through a glycosidic bond.

or

 Disaccharides consist of two monosaccharide units linked together. They are broken down into their monosaccharide components during digestion. Notable disaccharides include:

  • Sucrose (Glucose + Fructose) : Common table sugar, composed of glucose and fructose.
  • Lactose (Glucose + Galactose) : Milk sugar, made up of glucose and galactose.
  • Maltose (Glucose + Glucose) : Formed from two glucose molecules; found in germinating grains.


3. Oligosaccharides

Oligosaccharides are carbohydrates composed of 3 to 10 monosaccharide units. They are found in foods like legumes, onions, and garlic. Oligosaccharides play roles in cell recognition and serve as prebiotics, promoting beneficial gut bacteria growth.

It is a short chains of monosaccharides linked by glycosidic bonds.

Examples:

Raffinose (Galactose + Glucose + Fructose) – Found in beans

Stachyose – Found in legumes

Mannan-oligosaccharides (MOS) – Used in animal feed as a prebiotic


Types of Oligosaccharides are :

  • Diasaccharide
  • Trisaccharide
  • Tetrasaccharide
  • Pentosaccharide
  • Hexasaccharide
  • Octosaccharide
  • Nonsaccharide
  • Secrosaccharide

4. Polysaccharides

Polysaccharides are complex carbohydrates consisting of long chains of monosaccharide units. They serve as energy storage or structural components in organisms.

These carbohydrates contain more than 10 monosaccharide units. They further classified into homosaccharide and hetrosaccharides.

 Key polysaccharides include:

  • Starch: The primary energy storage in plants; found in foods like potatoes, rice, and wheat.
  • Glycogen: The main form of energy storage in animals, stored in the liver and muscles.
  • Cellulose: A structural component of plant cell walls; it is a major source of dietary fiber for humans.

Two types:

I. Storage Polysaccharides (Energy storage)

Starch – Found in plants (e.g., rice, wheat, potatoes)

Glycogen – Found in animals (stored in liver and muscles)

 

II. Structural Polysaccharides (Support and protection)

Cellulose – Found in plant cell walls (fiber)

Chitin – Found in fungal cell walls and insect exoskeletons


Understanding these types of carbohydrates is essential, as they have different impacts on health and nutrition. For instance, while monosaccharides and disaccharides are quickly absorbed and can cause rapid spikes in blood sugar levels, polysaccharides provide sustained energy and aid in digestive health due to their fiber content.