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4.1 Classification and structure of carbohydrates

2 min readLast Updated on August 7, 2024

Carbohydrates come in simple and complex forms. Simple carbs include single-sugar monosaccharides like glucose and fructose, and two-sugar disaccharides like sucrose and lactose. These provide quick energy and sweetness in foods.

Complex carbs have more sugar units. Oligosaccharides have 3-10 units and can act as prebiotics. Polysaccharides like starch and cellulose have many units, providing energy storage in foods and fiber for digestion.

Simple Carbohydrates

Monosaccharides

Top images from around the web for Monosaccharides
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  • Simplest form of carbohydrates consisting of a single sugar molecule
  • Glucose is the most common monosaccharide and primary source of energy for cells
    • Found in fruits, vegetables, and honey
    • Blood sugar refers to the concentration of glucose in the bloodstream
  • Fructose is another common monosaccharide known as fruit sugar
    • Naturally occurs in fruits, vegetables, and honey
    • Sweeter than glucose and often used as a sweetener in processed foods (high fructose corn syrup)

Disaccharides

  • Carbohydrates composed of two monosaccharide units joined by a glycosidic bond
  • Sucrose, commonly known as table sugar, is a disaccharide made up of glucose and fructose
    • Produced by plants and extracted from sugar cane or sugar beets
    • Widely used as a sweetener in food products and beverages
  • Lactose is a disaccharide found in milk and dairy products
    • Composed of glucose and galactose
    • Some individuals may be lactose intolerant due to a lack of the enzyme lactase needed to break down lactose

Complex Carbohydrates

Oligosaccharides

  • Carbohydrates containing 3-10 monosaccharide units linked by glycosidic bonds
  • Examples include raffinose (found in beans) and stachyose (found in soybeans)
  • Some oligosaccharides, such as fructooligosaccharides, act as prebiotics promoting the growth of beneficial gut bacteria

Polysaccharides

  • Carbohydrates composed of many monosaccharide units joined by glycosidic bonds forming long chains or branched structures
  • Starch is a storage polysaccharide in plants consisting of amylose (linear) and amylopectin (branched)
    • Major source of energy in the human diet found in foods like potatoes, rice, and wheat
    • Amylose has a linear structure of glucose units linked by α-1,4 glycosidic bonds
    • Amylopectin has a branched structure with glucose units linked by α-1,4 and α-1,6 glycosidic bonds
  • Cellulose is a structural polysaccharide in plant cell walls made up of glucose units linked by β-1,4 glycosidic bonds
    • Most abundant organic compound on Earth providing structure and support to plants
    • Humans lack the enzymes to break down cellulose, making it an important source of dietary fiber

Term 1 of 19

Amylopectin
See definition

Amylopectin is a highly branched polysaccharide and one of the two components of starch, the other being amylose. It plays a crucial role in the structure and function of starch in food products, providing the gel-like properties that are important in cooking and processing. Understanding amylopectin is essential for grasping how carbohydrates function in food science, particularly in applications involving thickening agents and texture modification.

Key Terms to Review (19)

Term 1 of 19

Amylopectin
See definition

Amylopectin is a highly branched polysaccharide and one of the two components of starch, the other being amylose. It plays a crucial role in the structure and function of starch in food products, providing the gel-like properties that are important in cooking and processing. Understanding amylopectin is essential for grasping how carbohydrates function in food science, particularly in applications involving thickening agents and texture modification.

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AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.

Term 1 of 19

Amylopectin
See definition

Amylopectin is a highly branched polysaccharide and one of the two components of starch, the other being amylose. It plays a crucial role in the structure and function of starch in food products, providing the gel-like properties that are important in cooking and processing. Understanding amylopectin is essential for grasping how carbohydrates function in food science, particularly in applications involving thickening agents and texture modification.



© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.

© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.
Glossary
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