Food Science

Question 1

What are the building blocks of protein?

Answer 1

Amino acids

Question 2

What is gelatinisation?

Answer 2

Process in which moist heat is applied to starch grains, which
swell, increase in size and burst, releasing amylose, which thickens
around boiling point.

Question 3

At what temperature does Starch start to absorb the liquid. Increase in volume.

Answer 3

60°C

Question 4

At what temperature does Starch swells 5x volume. Granules burst and release
amylose, which thicken the liquid.

Answer 4

80°C

Question 5

At what temperature is Gelatinisation complete

Answer 5

100°C

Question 6

What is Dextrinisation?

Answer 6

Dextrinisation occurs when
starch is broken down into
dextrin by dry heat

Question 7

Examples of dextrinisation

Answer 7

baking, grilling or toasting.
Dextrin adds a sweet taste to
baked products.

Question 8

Effects of dextrinisation

Answer 8

Dextrinisation contributes to the
colour and flavour of many
foods such as toast, bread and
croissants.

Question 9

What is caramelisation?

Answer 9

Caramelisation is one of the most
important types of browning
processes in foods.

Question 10

What is the process of caramelisation?

Answer 10

process of changing the colour of
sugar from white to brown when
heated.

Question 11

What does caramelisation cause?

Answer 11

causes important changes in foods,
not only in colour but also in flavour.

Question 12

What does caramelisation lead to?

Answer 12

It leads to a desirable golden brown
colour and an attractive flavour in
baked goods and drinks.

Question 13

What flavour does caramelisation give to food?

Answer 13

Caramelisation can give a buttery,
toasty or even a nutty flavour to food.

Question 14

What do amino acids do to create different proteins?

Answer 14

They join together

Question 15

What are proteins made of?

Answer 15

Protein are large molecules made up of amino acids

Question 16

What do proteins do?

Answer 16

They often fold into compact bundles due to their size
Chemical bonds hold the bundles together.

Question 17

What is denaturation?

Answer 17

The chemical bonds can be broken
and the protein bundles can
unravel.

Question 18

What can bonds be broken with?

Answer 18

• Heat
• Acids
• Mechanical agitation

Question 19

What is marinating?

Answer 19

Soaking meat or vegetables in liquid before
cooking

Question 20

What is often used for marinating?

Answer 20

Lemon juice or vinegar often used

Question 21

What does marinating tenderise?

Answer 21

Tenderises tougher cuts of meat as breaks
down fibres

Question 22

What is curdling?

Answer 22

Acid used to denature milk proteins

Question 23

Curdling in milk?

Answer 23

Milk develops a slightly lumpy appearance
as proteins clump together
Naturally occurs as milk ‘spoils’

Question 24

What process is curdling used in?

Answer 24

Used in cheese-making process

Question 25

Mechanical action-whisking?

Answer 25

• Proteins stretch when whisked
• They form a structure which
allows air to be trapped
• Tiny air bubbles form a foam

Question 26

Mechanical action-kneading?

Answer 26

• Kneading in bread-making
denatures the protein (gluten)
• Allows the dough to become
stretchy

Question 27

Mechanical action-mincing?

Answer 27

• Cutting up and mincing of meat
• Breaks up muscle fibres
• Makes food easier to eat

Question 28

What is coagulation?

Answer 28

Coagulation is the term used to describe the setting of protein.

Question 29

When does coagulation occur?

Answer 29

occurs when the protein is heated.

Question 30

Ways heated protein foods will
coagulate in different ways:

Answer 30

• Meat proteins shrink
• Egg white becomes solid and
turns white as it coagulates at
60°C.
• Egg yolk becomes solid and will
eventually become dry as it
coagulates at 70°C.
• Gluten will set and give cakes,
breads and biscuits their firm
structure.
• The milk proteins will coagulate
and form skin on heated milk, just
below boiling point

Question 31

What is syneresis?

Answer 31

Syneresis results from the over-
coagulation of egg protein.
(Water is pushed out of the egg)

Question 32

Where can syneresis be seen?

Answer 32

This can be seen in overcooked
scrambled eggs.

Question 33

Gliadin + glutenin =

Answer 33

Gluten

Question 34

What is gluten formation?

Answer 34

Gluten is flour protein

Question 35

What does gliadin do?

Answer 35

gives dough strength and
elasticity

Question 36

Foam formation?

Answer 36

Eggs are excellent at foam formation
• Any part of the egg can be whisked into a foam
• A foam = gas in a liquid
• Mechanical action of whisking makes the protein denature
• This is reversible if left to stand
• When heated, the air bubbles
expand and the protein coagulates
• This gives a firmness to the foam

Question 37

What is shortening?

Answer 37

Rubbing in ensures the fat coats the flour

Question 38

Explanation of shortening

Answer 38

Fat coats the flour particles,
preventing the absorption of water,
resulting in a crumbly mixture.
• The fat gives the flour particles a
waterproof coating.
• The fat prevents the flour from
absorbing water and reduces the
development of gluten.

Question 39

What is aeration?

Answer 39

Creaming the butter and sugar together

Question 40

Explanation of aeration?

Answer 40

When the fat and sugar are creamed
they enclose tiny bubbles of air.
The tiny bubbles of air make a stable
foam which can be baked to give the
springy texture.

Question 41

What is plasticity?

Answer 41

When butter is heated it melts and the
plasticity increases

Question 42

Explanation of plasticity?

Answer 42

Plasticity describes the ability of a solid
fat to soften over a range of
temperatur

Question 43

What is emulsification?

Answer 43

Oil and water are immiscible or
unmixable

Question 44

Emulsification explanation?

Answer 44

Tiny droplets of one liquid, such as oil,
are spread throughout another liquid
such as water.