Food Tech: Chapter 6 Flashcards
Define cooking
The transfer of energy from a heat source to food
Why do we cook food?
- cooking destroys harmful micro-organisms in food
- cooking destroys some of the enzymes that cause food to spoil and therefore extends the shelf life
- eating, digestion and adsorption of nutrients are made easier by the structural changes taken.
- the flavour is enhanced
- changes the texture
- aromas are released from food
- improve colour
- becomes less bulky
What is conduction ?
The process of cooking food by direct heat
How does conduction occur?
- Conduction of heat occurs when energy is moved from one particle to another by collision or movement.
e. g. Heat is conducted through the base of a saucepan when in contact with a gas flame, as the heat is transferred to the surface of the food, it is also transferred by conduction to the inside of the food, cooking it through.
What is convection?
- Convection is when the transfer of heat in liquids and air is brought about when the molecules move from a warmer area to a cooler one.
- It is a combination of conduction and mixing.
How does convection occur? (Liquid)
-Liquid: Convection takes place when cooking liquids are heated during the boiling and stewing of food. As the molecules absorb energy, they heat up and rise, sinking again when they cook off.
How does convection occur? (Air)
Convection currents are formed when an oven is heated. As the air in the oven is heated, it rises and forces the colder air at the top to flow down the sides of the oven, creating a current.
e.g. In an oven
What is radiation?
Radiation is the transmission of energy by wave motion in the form of electromagnetic waves.
e.g. cooking in a grill
How does radiation occur?
when the waves fall on food they cause the molecules in food to vibrate, which causes the food to heat up and subsequently cook.
- food does not come into contact with the heat source.
e. g. cooking under a grill or toaster
What is magnetic induction?
Heat in magnetic induction cooking is produced directly in the base of the saucepan, rather than on the cook top.
How does magnetic induction work?
An electric circuit supplies a current if power through a coil of copper wire, creating a magnetic field. When in contact with this magnetic field, the ferro-magnetic metal-based saucepan placed on the cooking zone is crossed by induction currents and heats up immediately.
-the saucepan heats up, rather than surface of the cook top.
Name the dry methods of cooking
- roasting
- baking
- grilling
- frying
Foods suitable for roasting
- red and white meats
- vegetables
Define roasting
Roasting is a method of cooking food in an oven using a minimum amount of fat or oil
Define Baking
Cooking food in an oven without the addition of fat or oil
Foods suitable for baking
- Fish
- Fruit
- Egg custard
- Combination dishes (lasagne, shepherd lie)
- Flour products
Safety practices for roasting and baking
- take care when lighting a gas oven
- use oven mitts to handle hot baking trays
- open the oven door completely
- do not leave the oven door open after removing food
- always check racks are in correct position before turning oven on
Define grilling
Grilling is a fast, dry methods of cooking that uses intense heat radiated by an electrical element, gas, flame, glowing charcoal or open wood fire.
Equipment for grilling
- Charcoal grills
- Grills I’m domestic ovens
- Overhead grills or salamanders
- Small appliance