Sugars

• How is a disaccharide formed?

  Through a condensation reaction between two monosaccharides. Joined with a glycosidic bond.
• What are carbohydrate?


  Made from monosaccarides (glucose, fructose, galactose)
• What’s the test for reducing sugar?

  • Add Benedict’s reagent to sample
  • Heat in water bath. If sample stays blue: no reducing sugar present, sample forms green-yellow-orang-brick red: reducing sugar is present
• What’s the test for non-reducing sugars?

  • Add dilute hydrochloric acid and heat in water bath to hydrolyse sample. Neutralise by adding sodium carbonate and repeat Benedict’s test
• Disaccharide examples

  • Maltose: two alpha glucose molecules
  • Sucrose: glucose + fructose
  • Lactose: glucose + galactose
• What is glucose 


  A hexose sugar, two types alpha and beta