Eggs

• Functions of eggs - Binding

  Binding is when the protein in the egg will coagulate (become thick and set) when heated, so it holds other ingredients together.

  e.g. fishcakes
• Functions of eggs - Thickening

  As the protein in the egg is heated, it coagulates and thickens the products.

  e.g egg custard
• Functions of eggs - Glazing

  Egg is brushed on the surface of a product, and when cooked the egg will form a shiny surface.

  e.g pastry topping
• Functions of eggs - Aeration

  The protein in the egg will stretch when it is whisked (denaturation) and this will allow air bubbles. When cooked it will solidify around the air.

  e.g meringue
• Food poisoning risk of eggs:

  • in ice cream, mousses, mayonnaise - eggs can be raw or undercooked.

  Raw or undercooked eggs are classed as a high risk food since they are moist, high in protein and support the growth of pathogenic bacteria. Once the shell is cracked, bacteria can contaminate the egg.
• safety and storage of eggs:

  • kept below 20 degrees celsius
  • kept away from strong smelling foods - egg shells are porous
  • wash hands before and after handling
  • eggs stamped with the British Lion Mark means that the hens were vaccinated and the eggs are safe to eat
• Protein is needed for growth and repair in the body.
• Emulsions

  Emulsify: to use an ingredient in a mixture enabling 2 ingredients to mix without the mixture separating. e.g egg yolk (contains lecithin)

  Emulsion: a fine dispersion of tiny droplets of 1 liquid in another

  
  

  Sauces such as mayonnaise is an example of an emulsion. Margarine and low fat spreads contain emulsifiers to stop the fat and water from splitting, this means the shelf life is longer which benefits the consumer.
• Explain how an egg yolk acts as an emulsion in mayonnaise.

  • contains lecithin
  • this contains molecules which have a hydrophobic and hydrophilic end
  • which holds the oil and water together in a suspended emulsion
• Whilst making mayonnaise, it splits. State a possible cause for this.

  Adding oil too quickly.