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Flashcards in Food science Deck (120)
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1
Q

Why do we need to cook foods?

A
To kill bacteria to make them safe
To soften the food so we can chew it
To make the food digestible
To improve and intensify the flavour
To make it look more attractive and appealing
To reduce the bulk of food
To provide variety to our meals
To enable certain foods to work together
To keep warm
2
Q

What are the three methods of heat transference used when cooking foods?

A

Conduction
Convection
Radiation

3
Q

What is conduction?

A

Transfer of heat by direct contact with a hot surface

4
Q

What is convection?

A

Transfer of heat by the movement of heated particles into a cooler mass/area

5
Q

Give examples of cooking methods that use conduction

A

Fry frying
Griddling
Searing
Sauteing

6
Q

Give examples of dry heat cooking methods that use convection

A

Baking

Roasting

7
Q

Give examples of wet heat cooking methods that use convection

A
Boiling
Braising
Simmering
Poaching
Steaming
Pressure cooking
8
Q

What is radiation?

A

Transfer of heat using waves of light or heat

9
Q

Give examples of cooking methods that use radiation

A

Toasting
Grilling
Barbecuing

10
Q

How does microwave radiation cook foods?

A

Radiation penetrates 1cm of the food
The radiation agitates the water molecules in food
Causes friction which spread heat energy around the rest of the food

11
Q

What is baking?

A

Food cooked in the dry, hot air of the oven

12
Q

Give examples of baked foods

A
Cakes
Pastries
Bread
Puddings
Biscuits
Fish
13
Q

What are the advantages of baking foods?

A

Good colour and texture
Several items can be cooked at once
Outside of food goes brown and adds flavour

14
Q

What are the disadvantages to baking foods?

A

Need specific cooking times

Need specific temperatures

15
Q

What is roasting?

A

Cooking food using the dry, hot air of the oven but fat has been added to stop it drying out

16
Q

What are the advantages to roasting foods?

A

Good flavour (added fat)
Crisp texture
Attractive appearance (golden brown)
More than one item can be cooked at a time

17
Q

What are the disadvantages to roasting foods?

A

Can take a long time (joints of meat)
Have to add extra fat (unhealthy)
Meat can become tough and chewy if cooked on too high a heat

18
Q

What is toasting?

A

Dry radiant heat applied to food. Can be directly onto foods.

19
Q

Give examples of foods that can be toasted

A

Bread
Nuts
Seeds
Whole spices

20
Q

What are the advantages to toasting foods?

A

Lower the glycaemic index (food takes longer to digest)
Flavours released
Flavours enhanced

21
Q

What is a disadvantage to toasting foods?

A

Need to be careful not to burn

22
Q

What is grilling?

A

Small pieces of food cooked by the radiant heat of a grill or barbeque

23
Q

What are the advantages of grilling food?

A

Healthy method - fat drains out of the food during cooking

Quick

24
Q

What are the disadvantages to grilling foods?

A

Need to be careful not to burn

Only tender cuts of meat should be grilled

25
Q

What is shallow frying?

A

Cooking small pieces of food in a small amount of hot oil/fat

26
Q

What are the advantages to shallow frying foods?

A

Quick method

Uses a minimal amount of fat

27
Q

What are the disadvantages to shallow frying/

A

Should not be left unattended
Unhealthy due to added fat
Wet foods can spit and splash when fried

28
Q

What is deep frying?

A

Foods are submerged in very hot fat/oil

29
Q

What are the advantages to deep frying?

A

Golden colour
Crunchy surface
Very quick

30
Q

What are the disadvantages to deep frying?

A

Can’t be left unattended
Very unhealthy
Over-heated fat/oil can combust and cause a fire

31
Q

What is stir frying?

A

Very small pieces of food quickly cooked in a small amount of oil/fat whilst being move continuously.

32
Q

What are the advantages to stir frying?

A

Very quick
Vegetables remain crunchy
Healthier frying method
Limited loss of water soluble vitamins

33
Q

What are the disadvantages to stir frying?

A

Needs constant attention and stirring
Needs fat/oil with high smoke point
Food needs to be fully prepared before cooking

34
Q

What cooking methods use dry heat?

A

Baking
Roasting
Toasting
Grilling

35
Q

What cooking methods use frying?

A

Deep frying
Shallow frying
Stir frying

36
Q

What cooking methods use moist heat?

A
Boiling
Simmering
Poaching
Stewing
Braising
Pressure cooking
Steaming
Blanching
Sous vide
37
Q

What is boiling?

A

Usually starchy foods cooked in boiling water

38
Q

What are the advantages to boiling foods?

A

Quick

Healthy as no fat is added

39
Q

What are the disadvantages to boiling foods?

A

Water soluble vitamins easily lost
Food becomes soft
Unsuitable for meats as it toughens the protein

40
Q

What is simmering?

A

Food submerged in water that is only gently bubbling

41
Q

What are the advantages to simmering foods?

A

Good for tender pieces of food as it is a gentle way to cook

42
Q

What are the disadvantages to simmering foods?

A

Tender food can fall apart if it becomes a boil

Loss of water soluble vitamins

43
Q

What is poaching?

A

Food cooked in a small amount of simmering liquid

44
Q

What are the advantages to poaching?

A

Tender foods cooked very gently
Healthy (no added fat)
Adds flavour if using something other than water

45
Q

What are the disadvantages to poaching?

A

Loss of water soluble vitamins
Foods can break apart
Can taste bland if only poached in water

46
Q

What is stewing?

A

Foods submerged in liquid, cooked slowly.

47
Q

Whats the difference between a stew and a casserole?

A

Stew is cooked on the hob

Casserole is cooked in the oven

48
Q

What are the advantages to stewing?

A

Tough meats are tenderised
Good flavour
Water soluble vitamins absorbed into the sauce

49
Q

What are the disadvantages to stewing foods?

A

Takes a long time (2-3 hours) so need to plan ahead

50
Q

What is braising?

A

Usually in the oven
Vegetables and liquid at the bottom of the cooking pan, meat is on top so is steamed
Needs a good fitting lid

51
Q

What are the advantages to braising?

A

Tough meats are tenderised
Good flavour
Water soluble vitamins absorbed into the sauce

52
Q

What are the disadvantages to braising?

A

Take a long time to cook (1-2 hours) so need to plan ahead

53
Q

What is pressure cooking?

A

Cooked in a sealed pan where the temperature of boiling liquid can be increased to 105-120oC

54
Q

What are the advantages to pressure cooking?

A

Really quick (3 x quicker than boiling)
Tough meat is made tender
Less fuel used
Water soluble vitamins not lost so easily

55
Q

What are the disadvantages to pressure cooking?

A

Easy to over cook foods
Food can become soft
Liquids can quickly cook away so the food burns

56
Q

What is steaming?

A

Cooking in the steam of boiling water

57
Q

What are the advantages to steaming foods?

A

Water soluble vitamins not lost
Really healthy way of cooking
Food is easy to digest

58
Q

What are the disadvantages to steaming foods?

A

Can take longer than boiling
Have to remember to fill the steamer up with water
Kitchen can fill with condensation

59
Q

What is blanching?

A

Food is plunged briefly into boiling water or steamed, removed and then places into chilled water

60
Q

What are the advantages to blanching foods?

A

Healthy
Keeps green and brightly coloured foods bright
Retains flavour, colour and texture as it stops enzyme action

61
Q

What are the disadvantages to blanching foods?

A

Vitamins and minerals can be lost

Not suitable for all foods

62
Q

What is sous vide?

A

Vacuum packed foods cooked at very precise temperatures

63
Q

What are the advantages to cooking foods sous vide?

A

Little loss of moisture or weight
Flavour and aroma of foods preserved
Nutrients not lost into cooking water
Consistent results

64
Q

What are the disadvantages to cooking foods sous vide?

A

Water bath is expensive

Foods do not brown

65
Q

What are the disadvantages to microwave cooking?

A

Cold spots can form so foods must be stirred during cooking
Food needs to be left to stand once cooked
Can only use for foods that have a high water content
Foods do not go brown or crispy
Metal containers cannot be used

66
Q

What are the advantages to microwave cooking?

A

Quick

Easy

67
Q

What happens to proteins when they are cooked?

A

They denature (unravel) and coagulate (set)

68
Q

Is the denaturation (unravelling) of proteins reversible?

A

No

69
Q

Between what temperature do most proteins coagulate?

A

71-85oC

70
Q

What term describes proteins and carbohydrates cooking and developing a brown colour and charred flavour?

A

Maillard reaction

71
Q

What does the term plasticity mean in relation to fats?

A

How fats soften and liquify when heated

72
Q

Can fats evaporate?

A

No

73
Q

When cooked what does fat add to foods?

A

Colour and flavour

74
Q

What does the term gelatinisation mean?

A

When starch granules and liquid are heated the granules soften and swell whilst absorbing liquid this causes the mixture to thicken e.g. roux sauce

75
Q

At what temperature do starches start to gelatinise?

A

66oC

76
Q

What does the term dextrinisation mean?

A

When starches and cooked by dry heat and turn brown

77
Q

What does the term caramelisation mean?

A

When sugar is cooked and turns brown and changes flavour

78
Q

What happens to water in foods during cooking?

A

Heats up, turns to steam and then evaporates

79
Q

What is the pH value of neutral foods?

A

pH 7

80
Q

What can acids do during cooking?

A
Soften connective tissue in meat
Give meringues a marshmallowy texture
Set proteins in milk to make cheese
Preserve fruits and vegetables
Denature proteins when used as a marinade
81
Q

What can alkalis do during cooking?

A

Act as a raising agent

Destroy vitamin C

82
Q

What term describes fruits and vegetables going brown when exposed to oxygen?

A

Enzymic browning

83
Q

What gives red meat its bright red colour?

A

Myoglobin

84
Q

What colour do red meats go during storage?

A

Brown/burgundy

85
Q

What term describes fats that have been exposed to oxygen for too long?

A

Rancid

86
Q

Why are meats hung after slaughtering but before butchering?

A

So that enzymes can soften muscle fibres and develop the flavour

87
Q

Give examples of the use of microorganisms in food production

A

Yeasts in bread making
Lactic acid with milk to make cheese and yoghurt
Probiotics in yoghurt to aid digestion e.g. yakult
Lactic acid used to make salami, pepperoni and chorizo
Sauerkraut is fermeted cabbage
Soy sauce is fermented soya beans
Moulds to make blue cheeses
Mushrooms are edible fungus

88
Q

What are five methods of adding air to foods so it can act as a mechanical raising agent?

A
Sieving
Whisking
Rubbing in
Creaming
Lamination
89
Q

How does sieving add air to products?

A

Traps air as it is sieved and falls

90
Q

What are unleaved products?

A

Products made without a raising agent

91
Q

How does whisking eggs add air to products?

A

When eggs are whisked they trap air so create a foam

They trap air as the proteins unravel and stretch

92
Q

How does creaming products together add air?

A

As you cream fat and sugar together tiny bubbles of air are trapped. Shown when the mixture becomes pale and fluffy

93
Q

What is lamination in relation to pastry making?

A

Trapping air between the layers of pastry each time it is rolled and folded
Used in rough puff and flaky pastry

94
Q

How does air act as a raising agent?

A

When heated it expands so the food swells and rises creating a light and airy texture

95
Q

How does steam act as a raising agent?

A

During cooking water in mixtures becomes steam and forces its way upwards through the mixture creating hollow, risen foods

96
Q

What gas creates a light, airy texture in cakes?

A

CO2

Carbon dioxide

97
Q

Why is bicarbonate of soda used in products with a strong flavour?

A

Because it can have a strong soapy flavour

98
Q

What is yeast?

A

Microorganism

99
Q

What two forms can yeast be bought in?

A

Fresh

Dried

100
Q

What gas does yeast produce?

A

CO2

Carbon dioxide

101
Q

At what temperature does yeast produce gas the quickest?

A

Generally room temperature

Specifically 37oC

102
Q

What does yeast feed on?

A

Natural sugars found in flour

103
Q

What is the name of the process when yeast feeds on naturally occurring sugars?

A

Fermentation

104
Q

What two proteins form gluten?

A

Gliadin and glutenin

105
Q

What type of flour contains the most gluten?

A

Strong flour

106
Q

What is an emulsion?

A

Mixture of fat and liquid (that normally don’t mix)

107
Q

What emulsifier is used in mayonnaise?

A

Egg

108
Q

What is a foam?

A

A food that has been aerated

109
Q

What is added to foods to make a foam?

A

Gas

110
Q

What happens to the proteins in eggs when they are whisked?

A

Denature

111
Q

Why is flour commonly used in dishes?

A

Bulk (volume)

Thickening (gelatinisation)

112
Q

Why is fat commonly used in dishes?

A

Flavour
Moisture
Colour
Traps air

113
Q

Why are eggs commonly used in dishes?

A

Colour
Flavour
Set a liquid (coagulation)
Trap ait (aeration)

114
Q

Why is sugar commonly used in dishes?

A

Flavour
Colour
Texture

115
Q

At what temperature does water boil?

A

100oC

116
Q

What does the term heat transfer mean?

A

The way heat moves from one area to another through conduction, convection or radiation

117
Q

What does the term denaturation mean?

A

Altering a proteins molecular characteristics

118
Q

What is the maillard reaction?

A

Chemical reaction between protein and starchy carbohydrates that turns foods brown e.g. charred steak

119
Q

What does the term unleavened mean?

A

Breads and other baked goods made without a raising agent

120
Q

What does the term plasticity mean?

A

The ability of fat to hold its shape (how soft it is)