Carbohydrate – Terms to Know

Click Here to go to the next page

Types of Carbohydrates

RCACC Study Guide 2016: 

  • Identify important food sugars, the chemical reactions they participate in, and their functional properties.

Major carbohydrate terms

The following is an outline of Culinology Text Chapter 2, page 22 – 24, Carbohydrates.

  • Carbohydrates are composed of carbon, hydrogen, and oxygen with one molecule of water for each of carbon.
  • Carbohydrates contribute 4 kcal/g in foods
  • Simple Sugars -Monosaccharides 
    • Glucose – Aldehyde
    • Fructose – Ketone
    • Galactose – Aldehyde 
    • Common monosaccharides in foods are hexoses, contain 6 carbon atoms
    • All monosaccharides can participate in non-enzymatic browning reactions and are called reducing sugars
    • The –OH (hydroxyl) groups enable hydrogen bonding with water and make them highly water soluble.
  • Disaccharides 
    • Monosaccharides can join together via glycosidic linkages (covalent bonds) to form disaccharides 
      • Sucrose (glucose + fructose) the only nonreducing sugar and does not participate in non-enzymatic browning, such as Maillard reaction.
      • Maltose (glucose + glucose)
      • Lactose (glucose + galactose)
  • Oligosaccharides (2 to 10) monosaccharides 
  • Polysaccharides more than 10 units up to 15,000 
    • Constitute more than 90% of the carbohydrates found in nature. 
    • They form the rigid polymer structures that give plants their shape.
    • The many hydroxyl groups along polysaccharides facilitate hydrogen bonding with water molecules.
    • The large structures entrap large volumes of water allowing them to thicken 
    • Can also form gels by intermolecular interactions between them.
    • Starch is found in granules in nature and is the major form of energy stored in higher plant, seeds, roots, fruits, leaves.
    • Amylose is a long chain of repeating glucose molecules, in a single line (See figure 2.5 page 23)
    • Amylopectin is a branched chain of glucose molecules (See figure 2.5 page 23)
    • Fiber the monosaccharides hooked together in a way humans cannot digest so therefore provide 0 kcal/gram.
    • Cellulose, hemicellulose, pectin, chitin, inulin, and gums are examples of fibers. 
    • Glycogen is the only animal source of carbohydrate and it is stored in small amounts in human and animals. It is generally metabolized during the aging of meat.
  • Non-starch polysaccharides are used as food ingredients for thickening, stabilizing and/or gelling abilities.
    • Examples include pectins, plant seed gums, plant exudate gums, seaweed gums, bacterial gums, and cellulose gums.
    • May be composed of fructose and lactose in addition to glucose. 

Reading

  • Culinology text Chapter 2 pages 22-24
  • Essentials of Food Science, Chapter 3 pages 27-37