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Stearic acid

Palmatic acid

Oleic acid

Linoleic acid a

Linoleic acid b

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Who wants a glass of liquid consisting of 50% water, 20% saturated animal fat, 10% unsaturated animal fat, 10% animal protein and 8% carbohydrate (in the form of sugar of course)?!

Guess what? It contains vitamin A, B and D, loads of potassium and calcium and a sprinkling of magnesium.

Sounds great Dad!

You must be kidding

Homer.

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Starter activityWhat do paint, milk and mayonnaise have in common?

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Big picture…

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What are emulsifiers?

MUST: Describe how to get oil and water to mix.

SHOULD: Use labelled diagrams to show how an emulsifying agent works.

22 April 2023

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Oil and water• Oil and water do not mix –

we say they are immiscible• Think about oil slicks• But there are ways of mixing

oil and water – think about washing up

• The detergent acts as an emulsifier, and turns the unmixed liquids into an emulsion, so the grease can be washed off.

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This end is attracted to w…………….

This end is attracted to the o……

Explain how an emulsifier works using a flow diagram of pictures.

1. Oil and water do not mix (layers)

2. Add emulsifier and shake – describe what happens (and draw)

Salad cream is an emulsion – in what way is it different from the oil, water and vinegar that it is made from?

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Making emulsions

Oil Shake

Add water

Add 5 drops of egg yolk and shake

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Your diagram

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Review test - foundation1. State three ways to cook food.2. Give two reasons why cooking food is important.3. List two sources of protein.4. List two sources of carbohydrate.5. What gas is produced when baking powder is

heated?6. List two advantages and two disadvantages of

using food additives.7. State the five groups of food additives.8. What is the name of a chemical that helps oil and

water to mix?

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Review test - higher1. Describe three reasons why some foods should be cooked.2. List three sources of protein and three sources of

carbohydrates.3. What happens to protein molecules when they are cooked?4. Baking powder is sodium hydrogencarbonate. Write a word

equation for its thermal decomposition.5. State two advantages and two disadvantages of using food

additives.6. State the five groups of food additives and explain why they

are used.7. Describe an example of active or intelligent packaging.8. Sketch the structure of an emulsifier molecule and label the

parts.

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Can you now…• State what you need to add to oil and water in

order to mix them?• Describe the structure of an emulsifier

molecule?• Draw a diagram to show how an emulsifier

works?