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Stearic acid. Palmatic acid. Oleic acid. Linoleic acid a. Linoleic acid b. You must be kidding Homer. 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)?!
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Stearic acid Palmatic acid Oleic acid Linoleic acid a Linoleic acid b
You must be kidding Homer. 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!
Starter activity What do paint, milk and mayonnaise have in common?
What are emulsifiers? 15 July 2014 MUST: Describe how to get oil and water to mix. SHOULD: Use labelled diagrams to show how an emulsifying agent works.
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.
Explain how an emulsifier works using a flow diagram of pictures. • Oil and water do not mix (layers) • Add emulsifier and shake – describe what happens (and draw) This end is attracted to w……………. This end is attracted to the o…… Salad cream is an emulsion – in what way is it different from the oil, water and vinegar that it is made from?
Making emulsions Add water Add 5 drops of egg yolk and shake Shake Oil
Review test - foundation • State three ways to cook food. • Give two reasons why cooking food is important. • List two sources of protein. • List two sources of carbohydrate. • What gas is produced when baking powder is heated? • List two advantages and two disadvantages of using food additives. • State the five groups of food additives. • What is the name of a chemical that helps oil and water to mix?
Review test - higher • Describe three reasons why some foods should be cooked. • List three sources of protein and three sources of carbohydrates. • What happens to protein molecules when they are cooked? • Baking powder is sodium hydrogencarbonate. Write a word equation for its thermal decomposition. • State two advantages and two disadvantages of using food additives. • State the five groups of food additives and explain why they are used. • Describe an example of active or intelligent packaging. • Sketch the structure of an emulsifier molecule and label the parts.
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?