Protein

• Denaturation- the chemical bonds in protein molecules can be broken by: heating food, mechanical agitation (Eg whisking eggs) adding acids (eg lemon juice) air bubbles (eg formed in meringue)
• Overcooking causes the coagulated protein molecules to tighten up and squeeze out the trapped water - the food will become dry And tough (eg over cooked meat, scrambled egg)
• Coagulation - as protein foods are prepared + cooked they change texture + become more solid denatured protein molecules unfold and join up with other Ones to form big groups as they coagulate, they trap air and water
• Egg white protein can strech and hold a large volume of air to produce a foam eg meringue
• Air is trapped in a gas in liquid foam by whisking eg egg whites for meringue
• structure of proteins: large polymers, made up of indivisual units called amino acids, folded into compact shapes, chemical bonds in th protein hold it together in its compact shapes. They stop it unfolding
• Chemical bonds?

  Forces that hold atoms together in a molecule
• Denatured proteins unfold and join up with ones to form big groups - they coagulate
• As they coagulate, they trap air and water
• Chemical bonds can be broken by heat, whisking, acids, air bubbles