Food Science Flashcards
What is denaturation?
Denaturation is when the chemical bonds have broken and the protein molecule has unfolded and change shape
Heat - e.g frying or boiling an egg
Acids - e.g when adding lemon juice to cream
Air bubbles - e.g whisked sponge mixture
What is coagulation ?
Coagulation is the joining together of lots of denatured protein molecules, which changes the appearance and texture of the food. ‘Denatured protein molecules are larger and take up more space than they used to’
Example - raw eggs being cooked
What is gelatinisation?
Gelatinisation is the swelling of starch granules when they are cooked with a liquid to the point where they are burst and realise starch molecules. This leads the mixture to thicken.
What is caramelisation?
The breaking up of sugar molecules when they are heated, which changes the colour, flavour and texture of the sugar as it turns crammed. (When sugar turns brown when they are heated up). The flavour gradually changes sweet to a toffee Carmel flavour to a bitter and burnt flavour. The texture of the sugar also changes from crystals of sugar to syrup which is when it cools down and becomes a brittle toffee.
Example - the colour of toffee.
What is emulsification ?
Emulsification is either keeping drops of oil or fat suspended in a liquid and preventing them from separating out or keeping drops of water suspended in an oil or a fat preventing them from separating out. Food products such as mayonnaise, milk and butter.
What is plasticity?
Plasticity is the ability of fat to soften over a range of temperature and be shaped with light pressure. The plasticly of fats enables us to carry out the process such as spreading raw cake mixtures into a cake tin, pipping buttercream onto cakes, spreading cream cheese onto crackers. The plasticly of fats are due to their chemical structure.
What is enzymic browning?
The discolouration of a fruit or vegetable due to the reaction of enzymes with plant cell substances and oxygen from air.
What is shortening?
Shortening is the ability of fats that shorten the length molecules in pastry. Such as a shortcrust pastry and shortbread have a very tender crumbly ‘melt in the mouth’ texture when they bake. This is because they have a relatively high fat content.
What is Dextrinisation?
Dextrinisation is the breaking up of starch molecules into smaller groups of glucose molecules when they are exposed to dry heat. When foods contains starch such as bread, cakes, biscuits are cooked by dry heat they develop a brown colour on the outside. This is partly due to the heat reacting with the starch molecules which break smaller groups of glucose.
