C1F

Meat and eggs are good sources of protein. The protein molecules change shape as a result of the heat energy they absorb. This is called denaturing and it is permanent. Denaturing causes changes in the appearance and texture of the meat and eggs when they are cooked. For example:

• meat becomes firmer and turns from red to brown
• egg white solidifies and becomes white instead of transparent.

Raw potato is hard and has an unpleasant taste but it becomes softer and easier to digest when is cooked. This is beacuse:

• the cell walls break, leading to a softer texture
• the starch grains in the cells swell and spread out.

Emulsifiers are molecules that have two different ends:

• a hydrophilic end - 'water-loving' - that forms chemical bonds with water but not with oils
• a hydrophobic end - 'water-hating' - that forms chemical bonds with oils but not with water.