Food Science Flashcards
Give 6 example of why food is cooked
- to destroy harmful bacteria (e.g chicken)
- to develop flavour (e.g spice in curries)
- to allow for foods to rice, thicken, set (e.g cake)
- to change the texture (egg)
- to improve shelf life (milk)
- to make food hot (soup)
What is cooking defined as?
The transfer of energy from a heat source to a food
What are the different ways that heat can transferred into foods?
Conduction, convection, radiation
What is conduction?
The movement of heat from one item to another via direct contact
This causes a
(Movement of heat from the surface of the food to its interior)
What are some examples of cooking methods using conduction?
Frying in a pan
Stir frying
Baking and roasting if in contact with the tray
What is convection ?
The transfer of heat through a fluid, which may be liquid or gas
What are the two types of convection and how do they work?
NATURAL
- occurs because warm liquids and gases rise while cooler fall
MECHANICAL
- relies on fans or storing to circulate heat more quickly and evenly
What are examples of cooking methods using convection?
Boiling
Poaching
Steaming
Simmering
Baking
Roasting
Deep frying
What is radiation?
Something that doesn’t require physical contact between heat source to cook it
What are the two types of cooking that uses radiation?
Infrared
- uses an electric or ceramic element heated to such a high temperature it gives off waves of radiation that cook food
Microwaves
- radiation penetrates food agitating water molecules creating friction heat.
What are some examples of cooking methods using radiation?
Infrared
- toasters, BBQs, grills, blowtorch
Microwave
What influences the methods of cooking used? (5 examples)
Type of food being cooked
Facilities available
Time available
Skill of the cook
Choice like trying to be healthy
What are dry-heat cooking methods?
Ones where heat is using air or fat to cook foods
Describe how foods are cooked by GRILLING
Heat transfer by radiation
High temp therefore foods must be turned to ensure even cooking and should not be more the 3.5 cm thick
Examples of foods: meat steaks, cheese toasty
Describe how foods are cooked by BBQ GRILLING
Heat transferred by radiation
Foods must be turned to ensure even cook
Examples of foods; tofu, corn on the cob, sausages
Describe how foods are cooked by ROASTING/ BAKING
Heat transfer by convection then conduction
Examples of foods; meats, root vegetables, cakes
Describe how foods are cooked by SAUTÉING/ STIRFRYING
Food is coated in small amount of oil to prevent sticking and cooked at high heat
Describe how foods are cooked by SHALLOW FRYING
Foods are cooked in a pan with a medium amount of oil
Describe how foods are cooked by DEEP FRYING
Food is fully submerged in hot fat/oil
What is cooking using moist heat?
The cooking of food that involves water or steam
Describe how foods are cooked by POACHING
Cooking food in a pan of liquid below boiling point (around 80oc)
Describe how foods are cooked by SIMMERING
Foods cooked in liquid held slightly below boiling after it has boiled
Describe how foods are cooked by BOILING
Heating in a pan of boiling liquid
Describe how foods are cooked by STEAMING
Cooking food with steam from boiling water or stock
Describe how foods are cooked by BLANCHING
Part cooking food in blocking water for short time then immediately putting it in cold water
Describe how foods are cooked by BRAISING
Slowly cooking food ina liquid (oftern with herbs and veg)in an ovenproof dish with its lid on.
Describe how foods are cooked by STEWING
Describe how foods are cooked by MICROWAVING
How much is a portion of fresh fruit?
80g
How much is a portion of dried fruit?
30g
Give four benefits of eating the recommended portions of fruit and vegetables
-provide fibre preventing constipation
Provides water soluble vitamins
Contains antioxidants
Low in fats ans salt
What is red meat classified as
Lamb, beef, pork
What is processed meat classified as?
Smoked, salts, cured meats
Like bacon, ham, salami
What is the maximum recommended g of processed meats and why do you decrease from 90g?
Cut down to 70g due to high saturated fats and increased bowel cancer risk
What is the function of butter in recipes?
Improves flavours
Improves appearance
Traps air when creamed (helping rising)
Plasticity - mouldable to trap air
Shortening effect -coating flour to prevent gluten
Prevents lumps in sauces
Prevents sticking
Retains moisture
What is the function of flour in recipes
Gluten
Kneading stretches gluten
Resting prevents shrinkage
Gluten formation provides structure
Gelatinisation
What is the function of sugar in some recipes? (11 things)
Sweetness
Reduces acidity
Caramelisation
Maillard reaction
Aeration
Attracted to water - maintains moisture
Prevents gluten forming - absorbs water
Increases coagulation temperature
(So prevents curdling, decreases viscosity,)
Speeds fermentation
Preservative
Prevents enzymatic browing
What is the function of eggs in recipes?
Emulsify
Glaze
Garnish
Foam
Aeration
Coagulation
Thickening
Bind
Enrich
Coat
What is the function of meat
Can be tenderised by;
-chemical action (Lemon/ vinegar)
-mechanical action. (Reducing length of muscle fibres by beating or crushing)
What are the advantages of food preservation?
Prevents enzyme action
Lasts longer
Use out of season
Slows microorganism growth
Increases variety and range of foods
Increases shelf life
Saves time to prepare
Less wastage
what are the disadvantages of food preservation ?
Often higher in fat, salt, sugar
Lower fibre
May loose nutrients
Additives may be added to restore colour
Can be more expensive
Texture changes
