C1f: Cooking and Food Additives

Cooking involves chemical reactions in food to develop a different texture and taste. This item considers the chemical changes that happen to some foods when they are cooked. Much of the food eaten today contains food additives to colour food, enhance the flavour, add vitamins, stabilise the food, or stop it decaying. This item considers different types of food additive and some of the issues concerned with their use. This item provides the opportunity to collect and analyse secondary data using ICT tools when researching food additives and provides opportunities for interpreting and applying science ideas. 

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What three things might be recognisable once a chemical change has taken place?
There is a new substance made, the process is irreversible and an energy change takes place.
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What two reasons explain why cooking food is a chemical change?
A new substance is formed and the process can't be reversed.
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Name four food additives.
Emulsifiers, food colours, flavour enhancers and antioxidants.
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Describe the function of antioxidants.
They stop food reacting with oxygen
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Describe the function of food colours.
The give food an improved colour
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Describe the function of flavour enhancers.
They improve the flavour of food
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Describe the function of emulsifiers.
Help oil and water to mix and not separate.
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How does baking powder help cakes to raise?
Baking powder is used for baking cakes. It contains sodium hydrogencarbonate, which breaks down when heated to form carbon dioxide gas. The carbon dioxide helps to make the cake mixture rise, so that it is light and fluffy.
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What is the test for carbon dioxide?
Limewater turns cloudy white when carbon dioxide is bubbled through it.
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What are meats and eggs a good example of?
Proteins.
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Describe what happens to proteins when they are cooked.
The protein molecules change shape as a result of the heat energy they absorb. This is called denaturing and it is permanent. Denaturing causes changes in the appearance and texture of the meat and eggs when they are cooked.
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Describe the change of eggs after they are cooked.
Egg white solidifies and becomes white instead of transparent.
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Describe the change of meat after they are cooked.
Meat becomes firmer and turns from red to brown
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Why are potatoes easier to digest once they have been cooked?
The cell walls rupture which results in a loss of rigid structure and a softer texture, and starch grains swell up and spread out.
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What two ends does an emulsifier have?
Hydrophilic and hydrophobic.
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Why do emulsifiers help to keep oil and water from separating?
Because the hydrophilic end bonds to water molecules, and the hydrophobic end bonds with oil or fat molecules.
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What is the word equation for the decomposition of sodium hydrogencarbonate.
Sodium hydrogencarbonate = Sodium Carbonate + Carbon Dioxide + Water
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What is the balanced symbol equation for the decomposition of sodium hydrogencarbonate.
2NaHCO˅3 = Na˅2CO˅3 + CO˅2 + H˅2O
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Other cards in this set

Card 2

Front

What two reasons explain why cooking food is a chemical change?

Back

A new substance is formed and the process can't be reversed.

Card 3

Front

Name four food additives.

Back

Preview of the front of card 3

Card 4

Front

Describe the function of antioxidants.

Back

Preview of the front of card 4

Card 5

Front

Describe the function of food colours.

Back

Preview of the front of card 5
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