The science of cooking food

Question 1

Why do we cook food?

Answer 1

• Kill pathogens and toxins to make food safe to eat
• To soften the food and make it easier to few and swallow
• Make food more digestible
• Improve and intensify the flavour
• Make food more attractive/appealing
• To reduce bulk in food
• Give variety to a meal
• Enable ingredients to work together

Question 2

What is conduction?

Answer 2

The transfer of heat by direct contact with a hot surface. This is a slow method of heat transfer. Eg. cooking in a pan

Question 3

What is convection?

Answer 3

The transfer of heat by the mass movement of heated particles into a cooler mass or area. Dry heat eg. baking or roasting. Wet heat eg. boiling and braiding

Question 4

What is radiation?

Answer 4

The heat is transferred using electromagnetic radiation waves of heat or light strike the food. Grilling, toasting etc.

Question 5

What happens to protein when cooking food?

Answer 5

It denatures and coagulates. The structure of the protein is irreversibly changed resulting in a loss of moisture, shrinkage and becoming firm.

Question 6

What happens to carbohydrates when cooked?

Answer 6

The change that starch undergoes is called gelatinisation. The starch granules absorb water causing them to soften and swell up, this thickens the liquid.

Question 7

What is caramelisation?

Answer 7

Happens when sugar is cooked
Food gradually turns brown and changes flavour. Responsible for the colour and flavour of baked products and browning of meat and veg.

Question 8

What type of raising agent is sieving?

Answer 8

Mechanical

Question 9

What type of raising agent is whisking?

Answer 9

mechanical

Question 10

What type of raising agent is rubbing in?

Answer 10

Mechanical

Question 11

What type of raising agent is creaming?

Answer 11

Mechanical

Question 12

What type of raising agent is lamination?

Answer 12

Mechanical

Question 13

What type of raising agent is bicarbonate of soda?

Answer 13

Chemical

Question 14

What type of raising agent is baking powder?

Answer 14

Chemical

Question 15

What type of raising agent is self raising flour?

Answer 15

Chemical

Question 16

What type of raising agent is yeast?

Answer 16

Biological

Question 17

Why are emulsions needed?

Answer 17

A mixture of water and oils

Question 18

What is an unstable emulsion?

Answer 18

When the emulsion isn’t permanent. Eg, putting water and oil in a jar and shaking it. It will separate after a short period of time.

Question 19

What is a stable emulsion?

Answer 19

An emulsion that will be maintained even if left for a long period of time. Eg. mayonnaise. Egg yolk is a good emulsifier

Question 20

What fault is caused when there’s too much flour?

Answer 20

Stodgy, dry cake, break or biscuit

Question 21

What fault is caused when there’s too little flour?

Answer 21

Lacks bulk/volume.

Sauce/cake is soft and runny

Question 22

What fault is caused when there’s too little sugar?

Answer 22

Affects flavour

Question 23

What fault is caused when there’s too much sugar?

Answer 23

food is too brown, sweet or crisp

Question 24

What fault is caused when there’s too much egg?

Answer 24

Tastes dense and eggy

Question 25

What fault is caused when there’s too little egg?

Answer 25

Coagulation process is compromised

Question 26

What fault is caused when there’s too much liquid?

Answer 26

Correct batter consistency isn’t achieved

Question 27

What fault is caused when there’s too little liquid?

Answer 27

Dry mixture

Question 28

What fault is caused when there’s too little raising agent?

Answer 28

baked products don’t rise

Question 29

What fault is caused when there’s too much raising agent?

Answer 29

Cracked cake surface