foodtech unit 2 sac 2

principles of heat transfer

conduction, convection, radiation

conduction

heat is transferred between substances that are in direct contact with each other

convection

heat is transferred through circulation of hot fluid that surrounds the food

radiation

heat is transferred indirectly by electromagnetic waves which behave like light, heating the surface of food but not penetrating it, the interior of food is heated by conduction

dry cooking techniques

food is exposed to a source of heat in the absence of water or steam

process of microwaving

microwaves release electromagnetic waves that heat the water inside food by pushing the pieces that water is made of to make them go faster, as they move faster they get hotter which makes the food warmer

moist cooking techniques

using liquid and steam for cooking

mechanical action

a human or machine action creating the force and motion that causes a change to the properties of food

examples of mechanical action

whipping, beating, sifting, rubbing in, creaming

fruit acids

fruit acids assist with the release of pectin and help with gel formation

aeration

adding air into food

denaturation

permanent structural change of protein molecules in food through heat, acids or mechanical action

coagulation

permanent change of a protein from a liquid into a solid through heat or acids

raising

to increase in size by adding yeast, baking powder or air

maillard reaction

the reaction that occurs when sugar or starch and a protein are present in food and dry heat is applied to produce a golden brown colour.

emulsification

mixing 2 liquids together that dont normally mix by adding an emulsifier

caramelisation

the browning of sugar when heat is applied

dextrinisation

the process that occurs when starch is exposed to dry heat, the starch breaks down into dextrin creating a golden brown colour

gelatinisation

starch granules absorb liquid in the presence of heat and thicken the liquid to form a gel