1. © ORCA Education Limited 2005
Preparing Food
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SHOW tom, tom.acs, 40, 68
PLAY Acknowledge
PLAY Explain
SAY Hello | Hi | Good Day,
SAY I am Tom. | My name is Tom. | I am the VT character Tom.
SAY ^PAUSE=300^ I will provide some extra guidance and information ^PAUSE=300^ during this {prez entation=presentation.} | I will help with some extra information during this {prez entation=presentation.} ^PAUSE=800^
SAY My colleagues may also give some help. | There are other characters who may also be called on to give some guidance. | Some of my colleagues may also help out. ^PAUSE=1300^
PLAY Explain2
SAY In this {prez entation=presentation} we will look at different ways to cook food.^PAUSE=1300^
PLAY Blink
SAY We will also consider what happens to food when it is cooked.^PAUSE=1300^
PLAY Announce2
SAY Just a few technical points first though. ^PAUSE=1300^
SAY While we are talking ^PAUSE=300^ you can ^EMPHASIS^Suspend us ^PAUSE=300^ or ask us to ^EMPHASIS^Resume ^PAUSE=300^ by right clicking on us and then choosing ^PAUSE=300^ Suspend ^PAUSE=300^ or Resume ^PAUSE=300^ from the menu.^PAUSE=1300^
PLAY Decline
SAY If you choose ^EMPHASIS^Hide ^PAUSE=300^ we will stop completely! ^PAUSE=1300^
PLAY Sad
SAY ^PAUSE=600^
PLAY Alert
SAY Oh yes! ^PAUSE=300^
SAY There are some terms that may be new to you.
SAY If you want to see them before the {prez entation=presentation} click on the New Words button.
PLAY Point225
SAY ^PAUSE=800^
SAY These keywords in the text are red and underlined, ^PAUSE=300^ if you click on a highlighted word you will see a ^EMPHASIS^short definition
PLAY GestureDown
SAY at the bottom of the page. ^PAUSE=800^
END
New
Words
© ORCA Education Limited 2005

2. What different ways are there to cook potato? *
Why Cook Food?
Cooking destroys harmful bacteria:
it is more appetizing
improves appearance, flavour, texture and smell
aids digestion
makes food easier to eat
preserves food to stop it decaying
improves and enhances flavour
gives variety in the diet
reduces bulk so more can be eaten.
What different ways are there to cook potato? *

3. The Transfer of Heat Heat energy is used for cooking.
Conduction from the hot
grill bars cook stripes
on the fish surface
Heat energy is used for cooking.
It can be transferred in three ways:
Conduction food
against the hot
casserole pan
Conduction; heat is conducted from one molecule to another.
Convection; liquids and gases create convection currents transferring heat to the food.
Convection
of stock
Radiation; heat travels from one object to another in waves or rays e.g. barbeque, grill or microwave.
The frying pan conducts
heat directly to the fish
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SHOW peedy, peedy.acs, 44, 68
PLAY Wave
PLAY Uncertain
SAY ^PAUSE=300^ You know^PAUSE=300^ this is ^PAUSE=300^ ^EMPHASIS^really uncomfortably hot here? ^PAUSE=1300^
PLAY Explain
SAY Oh well, ^PAUSE=1300^when baking bread in an oven, ^PAUSE=300^ there are two ways the heat is transferred. ^PAUSE=1300^
PLAY Blink
SAY Movement of air molecules in the oven set up convection currents so the hot air circulates around the oven and around the bread, ^PAUSE=300^ the hot air cooks the bread. ^PAUSE=1300^
SAY So one method is convection. ^PAUSE=1300^
PLAY Announce
SAY It says Peedy you are cooking. ^PAUSE=300^ Well thanks very much you are pretty good yourself!
PLAY Decline
SAY Heat energy is also transferred from heated air ^PAUSE=300^ to the baking tin ^PAUSE=300^ and ^EMPHASIS^then to the bread ^PAUSE=300^ and so the other method is conduction, which is through the hot surface. ^PAUSE=800^
SAY This one says Peedy ^PAUSE=300^ you are ^EMPHASIS^really cooking! ^PAUSE=1300^
PLAY Greet
SAY Thanks again, too kind ^PAUSE=300^ so many compliments. ^PAUSE=700^
2) SHOW tom, tom.acs, 12, 68
LOOP 5=Idle3_3 <+>
2) PLAY GestureLeft
2) SAY Over here stupid! ^PAUSE=300^ The ^EMPHASIS^convection heat from the grill is traveling through the air currents^PAUSE=300^ and ^EMPHASIS^cooking you!
2) PLAY PointLeft
2) SAY If he gets any closer to the grill he will be touching it ^PAUSE=300^ and then he will be cooked by conduction as well. ^PAUSE=1300^
2) SAY Peedy go and cool down I can smell parrot cooking! ^PAUSE=1300^<+>
PLAY LookRight
PLAY GetAttention
HIDE
2) SAY Grilling meat, ^PAUSE=200^ fish ^PAUSE=200^ ^EMPHASIS^or ^EMPHASIS^parrot^PAUSE=200^ that close to a heat source can be through radiation,^PAUSE=300^ and so we can have radiation directly from gas flame, ^PAUSE=200^ coals or an electric element. ^PAUSE=1300^
2) PLAY Explain
2) SAY Whereas in convection and conduction the heat is transferred ^EMPHASIS^through a medium ^PAUSE=300^ which can be a gas, ^PAUSE=200^ liquid ^PAUSE=150^ or solid. ^PAUSE=1300^
2) SAY What actually happens with radiation is that heat passes through space or a vacuum by means of ^EMPHASIS^electromagnetic ^EMPHASIS^rays. ^PAUSE=1300^
2) PLAY DontRecognize
2) SAY So there you go! ^PAUSE=300^
2) SAY There is a lot of science in cooking. ^PAUSE=1300^
2) PLAY Wave
2) END
Most food is cooked using more than one method of heat transfer.
Convection
of hot air
Heat from the coals
radiates to the food
Heat from the fire
heats the frying pan
How is heat transferred for baking bread? *

4. Moist Methods of Cooking
Food can be cooked in four ways according to how heat is applied.
Moist methods involve heat being applied through liquid such as water, milk, steam, stock, wine, etc.
This method uses relatively low temperatures over a long period.
Prolonged moist cooking causes water soluble vitamins C and B to be leached into the cooking liquid.
Some moist cooking examples are:
pressure cooking
stewing & braising.
poaching
simmering
steaming
boiling
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SHOW tom, tom.acs, 32, 68
PLAY Wave
PLAY GestureRight
SAY You need to consider the physical and working characteristics of the food when deciding which method of cooking to use. ^PAUSE=1300^
PLAY Explain
SAY For instance, ^PAUSE=300^ meat and fish are both foods that can be cooked using a moist method. ^PAUSE=1300^
PLAY Confused
SAY But they both cook differently. ^PAUSE=1300^
PLAY Announce2
SAY Both have a substance called collagen which holds the bundles of muscle {fibers=fibres} together but these dissolve when heated^PAUSE=200^ to gelatine. ^PAUSE=1300^
PLAY Explain2
SAY Meat also has elastin which binds the muscle together which does ^EMPHASIS^not dissolve. ^PAUSE=1300^
PLAY HandsOnHips
SAY This holds meat together while being cooked ^PAUSE=300^ while fish flakes and tenderises in a short time. ^PAUSE=1300^
SAY That is why meat can be cooked over a long period and fish, ^PAUSE=300^ being rather delicate, ^PAUSE=300^ is best cooked by using a gentle but quick method. ^PAUSE=1300^
SAY There is a right and a wrong way of cooking vegetables as well. ^PAUSE=1300^
PLAY Acknowledge
SAY Root vegetables such as turnip and swede^PAUSE=300^ go well in a casserole to make them soft and digestible. ^PAUSE=1300^
PLAY GestureLeft
SAY Whereas leafy green vegetables need to be cooked ^EMPHASIS^quickly in small amounts of water to prevent vitamin loss. ^PAUSE=1300^
PLAY Think
END
What type of foods would be suitable for this method? *

5. How does dry cooking change the nutrients in food? *
Dry Methods of Cooking
In dry cooking, as with these sausages in a commercial oven, heat is applied directly onto food.
Other examples are roasting, grilling and barbecuing.
During dry methods of cooking e.g. grilling (toasting) or baking, heat turns starch a light golden colour known as dexrinisation.
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SHOW tom, tom.acs, 42, 68
PLAY Wave
PLAY Surprised
SAY I love the smell of baking bread! ^PAUSE=1300^
PLAY Explain
SAY Dry cooking produces the most ^EMPHASIS^wonderful aromas. ^PAUSE=1300^
PLAY Pleased
SAY Dry methods of cooking involve high temperatures of up to two hundred and forty celsius.
SAY This suits food that need quick cooking like puff pastry ^PAUSE=300^ or for browning meat or vegetables. ^PAUSE=1300^
PLAY Announce2
SAY In an oven it is possible to cook more slowly at cooler temperatures,
SAY for example when baking a rich fruit cake. ^PAUSE=1300^
PLAY Explain2
SAY Dry cooking does give food that special {flavor=flavour} ^PAUSE=300^ but it can lead to the food drying out. ^PAUSE=1300^
PLAY Explain3
SAY The nutritional value of protein, ^PAUSE=300^ carbohydrates, ^PAUSE=200^ fats ^PAUSE=150^ and minerals are not affected ^PAUSE=300^ but some vitamin C and thiamin are lost as they are heat sensitive. ^PAUSE=1300^
PLAY HandsOnHips
SAY My favourite way of dry cooking is {barby-queueing=barbecuing} food over charcoal like kebabs, burgers and chicken. ^PAUSE=600^ It gives that added {flavor=flavour} to the food ^PAUSE=300^ especially if basted in a moist marinade.^PAUSE=1300^
PLAY Think
END
When sugar is heated under the grill, it turns brown called caramelisation.
How does dry cooking change the nutrients in food? *

6. What other method of frying is more healthy? *
Heat is applied through fats or oils.
Some fat is absorbed increasing the the fat content of the food cooked.
In frying high temperatures destroy heat sensitive nutrients.
In deep frying the food is immersed in fat or oil at up to 200ºc.
Butter or margarine can be used for shallow frying as temperatures are not as high.
Foods high in fat can be dry fried using non-stick pans.
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SHOW tom, tom.acs, 52, 68
PLAY Wave
PLAY GestureRight
SAY What is a more healthy method of frying? ^PAUSE=1300^
PLAY Think
PLAY Explain
SAY Well stir frying is ^EMPHASIS^much healthier with a lot less fat. ^PAUSE=1300^
PLAY GestureLeft
SAY This involves only a little oil to get started. ^PAUSE=1300^
PLAY Acknowledge
SAY The ingredients are just finely chopped, ^PAUSE=300^ thrown into the pan ^PAUSE=300^ and cooked quickly in their own juices so that few nutrients are lost. ^PAUSE=1300^
PLAY Pleased
END
What other method of frying is more healthy? *

7. Which foods are not suitable for microwave cooking? *
Microwave Cookery
Microwaves generate heat by electro-magnetic rays from a magnetron valve.
Magnetron Valve
Microwaves are reflected off the metal walls of the cooker and are absorbed by the food.
They vibrate millions of times a second causing friction and heat in the food molecules
Paper china and some plastics allow microwaves to pass through them.
This method of cooking is very quick, therefore there is less destruction of nutrients.
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SHOW tom, tom.acs, 32, 68
PLAY Wave
PLAY Announce2
SAY Some foods are not so appetizing when cooked in a microwave. ^PAUSE=1300^
PLAY Decline
SAY It is not possible to make food crisp in an ordinary microwave ^PAUSE=300^ so food may not develop their characteristic {flavors=flavours,} ^PAUSE=300^ {colors=colours} ^PAUSE=300^ or textures.
PLAY GestureUp
SAY Chicken will remain pale ^PAUSE=300^ and cakes will not be golden brown and crisp on top. ^PAUSE=1300^
PLAY Explain
SAY There are many advantages which include that they cook food quickly, ^PAUSE=300^ they are ideal for prepared foods^PAUSE=300^ and there is less destruction of nutrients. ^PAUSE=1300^
SAY Cooking vegetables in a microwave is ^EMPHASIS^ideal^PAUSE=300^ as their {color=colour} and {flavor=flavour} can actually be improved. ^PAUSE=1300^
PLAY Think
END
Which foods are not suitable for microwave cooking? *

8. Preserving Nutrients
Vegetables and fruit contain the water soluble vitamins B and C which dissolve into cooking water.
This loss can be minimised by careful preparation and cooking.
Cook with a lid on and cook for the minimum amount of time.
Eat cooked vegetables immediately.
Vegetable water can be used for gravy.
Steaming vegetables reduces loss of nutrients from leaching.
Oxygen in air and water encourages the destruction of vitamin C.
Avoid peeling as vitamins and minerals are under the skin.
Vegetables should be chopped quickly and leaf vegetables torn not cut to avoid tissue damage.
What is the best way to cook cabbage? *

9. Which Method of Cooking?
You have a chicken and some vegetables to cook.
Your choice of cooking method will depend on:
time for cooking and preparation
facilities available
nutrient loss and healthy eating need
the needs of the individual e.g. small child or adult
individual preference on taste, texture, smell and flavour.
From the points above decide on a set of circumstances..
..how would you then cook the chicken and vegetables? *

10. Macro-Nutrients & Heat
How has an increase in temperature caused these foods to change?
Protein foods like the meat are permanently changed called denaturation.
Meat like this chicken hardens and darkens.
Other proteins like eggs coagulate and set.
The starch grains in the stew break open and form a gel with the liquid called gelatinisation which thickens the liquid.
When toasting or baking as with the roll the dry heat turns starch to dextrin.
The fats in the meat melt to a liquid when heated.
Fats can decompose at a high temperature, give off a bluish haze and burst into flames called the flash point. *

11. Acids in Cooking
Acids effect flavour, appearance, texture and nutritional value of food.
There are several kinds of acid used in these foods.
Citric acid (lemon juice) helps pectin make a gel for the jam. It also prevents enzymatic browning of cut fresh fruit and coagulates protein in cold desserts using cream.
Acetic acid (vinegar) is used in preserves like chutney, it marinates meat to tenderise it and gives a sharp flavour to salad dressing.
Ascorbic acid (Vitamin C) is used as flour treatment for yeast fermentation.
Tartaric acid(cream of tartar) is used with bicarbonate of soda in baking.
Lactic acid starter is used to coagulate milk in cheese making. *
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SHOW tom, tom.acs, 42, 68
PLAY Wave
PLAY Acknowledge
SAY Just a quick extra on ascorbic acid. ^PAUSE=1300^
PLAY Explain
SAY Ascorbic acid is added to flour to improve the dough for making bread. ^PAUSE=1300^
PLAY Announce2
SAY It helps develop the gluten formed when protein and water are mixed. ^PAUSE=600^
PLAY Explain2
SAY The gluten of flour can stretch ^PAUSE=200^ and when heated {co-agg-ulates=coagulates,} ^PAUSE=150^ holding pockets of air which gives bread its texture. ^PAUSE=1300^
PLAY CrossArms
SAY So without it our bread would be like that heavy flat German bread, ^PAUSE=300^ Pumpernickel.^PAUSE=1300^
PLAY Confused
END

12. Alkalis These scones rely on alkalis for their light open texture.
Alkalis are used in cooking as raising agents.
When these are mixed with other ingredients and heated, a chemical reaction takes place and carbon dioxide is produced.
There are 3 types of chemical raising agents:
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SHOW tom, tom.acs, 45, 68
PLAY Wave
PLAY GestureRight
SAY So how are each of these ways different? ^PAUSE=700^
PLAY Point315
SAY Firstly {by-carbonat=bicarbonate} of soda produces soda, ^PAUSE=300^ steam ^PAUSE=300^ and carbon dioxide^PAUSE=300^ but leaves a strong alkaline taste. ^PAUSE=1300^
PLAY Explain
SAY The second option is {by-carbonat=bicarbonate} of soda plus added acid ^PAUSE=300^ (sour milk or cream of {tarter=tartar}) ^PAUSE=300^ which prevents that alkaline taste. ^PAUSE=1300^
PLAY Point225
SAY Finally baking powder which is a mixture of {by-carbonat=bicarbonate} of soda and acid ^PAUSE=300^ and therefore is convenient to use. ^PAUSE=1300^
PLAY Think
END
bicarbonate of soda
bicarbonate of soda and acid (sour milk or cream of tartar)
How are these 3 types different? *
baking powder.

13. Some words or terms to learn
Vocabulary
Some words or terms to learn
bacteria
pressure cooking
poaching
leached
water soluble
tissue damage
coagulate
tenderise
raising agents
conduction
convection
radiation
braising
microwaves
gelatinisation
marinate*

14. The Task
You can enter here a task for your students.

15. End End Show Acknowledgements
All images used in these presentations are the property of their owners, ORCA Education Limited and suppliers inc. Hemera Images, Jupiter Media Corp. and Animation Factory All rights are reserved. The Licence agreement applies to all elements of these presentations. ORCA.VT is a trademark of ORCA Education Limited
Microsoft Agent is the property of Microsoft Corporation, Redmond WA. ORCA Education Limited are licensed distributors of Microsoft Agent technology Licence The Microsoft Agent Technology elements including Peedy character may not be distributed beyond the constraints of this product licence
Microsoft Agent characters Susan and Tom are packaged with this product as part of the Vox Proxy development tools used by ORCA Education. They are not for resale or distribution beyond their use in these products