Protein

• • Protein molecules are often folded into compact bundles so they take up less space
  • Protein contains complex molecules which contain oxygen, carbon, hydrogen and nitrogen

  
• Denaturation is the breaking of the chemical bonds in protein which cause the protein to unfold and change shape
• Examples of denaturing proteins are:

  • adding acids
  • trapping air bubbles
  • mechanical agitation
  • heat
• Syneresis is when protein molecules coagulate too much, squeezing out the water they were once holding

  e.g: dry and chewy meat, rubbery and chewy scrambled egg
• Coagulation is when denatured protein molecules join together and trap water in the presence of heat. It is irreversible and changes the colour, texture and flavour of the food
• Strong plain flour is used for bread making as it has a high amount of gluten
• When a liquid is added to flour, it forms a gluten network called gluten
• Flour contains gliadin and glutenin
• Gluten gives dough the ability to be stretched and shaped during kneading and also makes it elastic
• When baked the gluten network in the dough traps the carbon dioxide bubbles, forming the soft and light texture and making it rise
• Example

  When making swiss roll, whole eggs and sugar are whisked together to make a whisked sponge mixture. They product a thick gas from trapping air pockets which produces a light spongy texture
• Dought being able to be stretched and shaped is ideal for bread making because the bread dough needs to be able to stretch when the carbon dioxide bubbles produced by the yeast make the dough expand and rise
• Resting a dough before baking it allows the stretched gluten relax, allowing the stretched coils of gluten molecules to gradually return to their original size and shape