• Enzymes can be added to?solutions?and are thereby considered?‘free’?or they can be?immobilised
• Immobilised enzymes are enzymes that have been bound to an?inert,?stationary?and?insoluble?material such as?alginate
• The substrate is then?passed over?the immobilised enzyme and the product is collected
• Advantages?to this method:
  • There is?no enzyme in the product?(the product is?uncontaminated) and therefore there is no need to further process or filter the end product
  • The immobilised enzyme can be?reused multiple times?which is both efficient and?cost-effective?(enzymes are?expensive)
  • Immobilised enzymes have a?greater tolerance of temperature and pH changes?(immobilisation often makes enzymes more?stable)
• A practical application of immobilised enzymes used in the food industry is in the?production of lactose-free milk:
  • Milk is a valuable source of nutrients containing protein, fat and the carbohydrate Lactose
  • 5-10% of the UK population are lactose intolerant
  • Lactose is a disaccharide that is broken down into glucose and galactose

Using immobilised enzyme to modify milk

• Using lactase as shown above is an efficient way to?remove lactose from milk?and to provide lactose intolerant individuals with a way of consuming milk without suffering intolerance symptoms:
  • The enzyme lactase can be immobilised using?alginate beads
  • Milk is run through the column of lactase-containing beads
  • The lactase?hydrolyses?the lactose in the milk to?glucose?and?galactose
  • This ensures the milk is lactose-free
  • It can also then be used to make?other lactose-free dairy products

Lactose is a disaccharide that is broken down by lactase into the monosaccharides glucose and galactose