Food Science

Question 1

Give 5 reasons as to why food is cooked?

Answer 1

1. To make it safe to eat
2. To improve shelf life
3. To develop flavours
4. To improve textures
5. To give variety in the diet

Question 2

What is conduction?

Answer 2

The transfer of heat energy through the vibration of particles

Question 3

What is convection?

Answer 3

The transfer of heat energy through gases (in a cycle)

Question 4

What is radiation?

Answer 4

The transfer of heat energy through waves of radiation

Question 5

Give a few examples of water based cooking methods?

Answer 5

1. Boiling
2. Steaming
3. Blanching
4. Simmering
5. Poaching
6. Braising

Question 6

What is braising, blanching, and poaching?

Answer 6

1. Braising - slowly cooking food in an ovenproof pot with the lid on
2. Blanching - part-cooking food in boiling water for a short time before putting it in cold water
3. Poaching - Putting food in a pan of liquid below boiling point (80 degrees)

Question 7

Give 2 fat based cooking methods?

Answer 7

1. Stir-frying

2. Shallow-frying

Question 8

What is a difference between dry frying and roasting?

Answer 8

Fat is added to food when its roasted but fat isnt added to food that is dry fried

Question 9

When food is cooked, the proteins d…. and c….

Answer 9

denature and coagulate

Question 10

What is coagulation?

Answer 10

When denatures protein molecules join together to other molecules and trap water between them

Question 11

Give an example of a food that uses trapped air?

Answer 11

Meringue

Question 12

Describe the process of gelatinisation?

Answer 12

1. When you heat starch granules with a liquid, the bonds between the starch molecules start to break, allow water molecules to enter. This causes starch granuels to swell in size and soften
2. Between 62, and 80, the granules burst open and release starch into the liquid
3. The release of starch causes liquid to thicken
4. When it cools, the liwuid solidifies and a solid gel is formed (used to make set desserts like custard)

Question 13

What is dextrinisation?

Answer 13

When starchy molecules are cooked with dry heat and the starch molecules in the food break down into smaller molecules called dextrins

Question 14

What is caramelisation?

Answer 14

When sugar molecules break down at a high temperature, turn brown and change flavour

Question 15

What does shortening do for food?

Answer 15

Gives food a crumbly texture

Question 16

Define plasticity?

Answer 16

Ability to be spread and shaped

Question 17

How does an emulsifier prevent oil and water from separating?

Answer 17

emulsifiers have two different ends, a hydrophilic and hydrophobic end. Water molecules bond to the hydrophilic side and oil molecules bond to the hydrophobic end to prevent them from separating

Question 18

Give examples of chemical raising agents?

Answer 18

• Baking Powder
• Bicarbonate of Soda
• Self-raising flour

Question 19

Give an example of biological raising agents?

Answer 19

Yeast

Question 20

What are two ways of giving rise to a bake, except for chemical and biological raising agents?

Answer 20

1. Adding steam to a bake by adding lots of liquid in it

2. Mechanical ways e.g. Beating/whisking/folding air into a mixture/folding into layers