1. Food additives 2 higher

2. What Does the Fungus Know That You Don't?
Does the fungus love McDonalds?
Chips and burgers left in the open air – see the fungus and bacteria grow!
Settling down activity
Students watch the time lapse video on diner food vs mcdonalds (fullof presevatives and other chemicals therefore not much bacterial growth)
Starter activity – question
Why is it hard to wash oily plates in hot water without a washing up liquid (detergent)? Slide 4
Demo – water and oil not mixing together
And then add washing up liquid slide 5
Explain about the detergent molecule – water and oil loving
Experiment – making mayonnaise
Safety!
You must not eat anything in the lab.
You will need:
test tube and cork
oil
water
egg yolk (you will use eggs with the lion stamp on them as these are salmonella free)
dropping pipette
Method
Pour oil into a test tube until it is a third full.
Add the same volume of water.
1. What happens?
Cork the test tube and shake. Leave for a minute.
2. What happens now?
Add five drops of egg yolk to the test tube. Cork and shake again.
3. What happens this time?
Conclusion
1. Describe what you found out during the experiment.
2. Egg yolk helps hold the oil and water together. What is it called? Circle the correct answer below.
immobiliser emulsifier undulation
Plenary
Worksheet C1b 4
Slide 10 Describe how an emulsifier helps to keep oil and water from separating using the words :
hydrophilic
hydrophobic
Extra question slide 12
Mustard powder is an emulsifier
Friendly staff but not very friendly food

3. Lesson outcomes E - State that oil and water do not mix
E - State that emulsifiers help oil and water to mix and not separate
C - Describe emulsifiers as molecules that have a water–loving part (hydrophilic) and an oil– or fat–loving (hydrophobic) part
C - State examples of foods that contain emulsifiers e.g. mayonnaise
A - Describe how an emulsifier helps to keep oil and water from separating using the words :
hydrophilic
hydrophobic

4. Detergent
Why is it hard to wash oily plates in hot water without a washing up liquid (detergent)?
Demo – water and oil not mixing together

5. Oil and water – don’t mix
But if you add washing up liquid (detergent), what happens?
A detergent in washing up liquid provides “hooks” between oil and water.
This is an example of an emulsion
A detergent is an emulsifier
Demo – water and oil not mixing together
And then add washing up liquid

6. A Detergent is an emulsifier
Detergent is made up of molecules that act in a very special way.
A detergent molecule is long and thin. One end of the detergent molecule is good at attaching to water and the other end is good at attaching to grease and oil.
You've seen that oil and water, by themselves, don't mix well. But if detergent is added, one end of the detergent molecules gets attached to the oil and the other end gets attached to water.
Water loving part
Oil loving part

7. Long molecule of a detergent

8. Examples of emulsions Milk Mayonnaise Emulsion paint
We all love smooth foods and they get that way through the use of emulsifiers
The classic emulsion is milk, a complex mixture of fat droplets suspended in an aqueous solution.

9. Experiment – making mayonnaise
Safety!
You must not eat anything in the lab.
You will need:
test tube and cork
oil
water
egg yolk (you will use eggs with the lion stamp on them as these are salmonella free)
dropping pipette
Method
Pour oil into a test tube until it is a third full.
Add the same volume of water.
1. What happens?
Cork the test tube and shake. Leave for a minute.
2. What happens now?
Add five drops of egg yolk to the test tube. Cork and shake again.
3. What happens this time?

10. Experiment – making mayonnaise
Conclusion
1. Describe what you found out during the experiment.
2. Egg yolk helps hold the oil and water together. What is it called? Circle the correct answer below.
immobiliser emulsifier undulation

11. Plenary
Describe how an emulsifier helps to keep oil and water from separating using the words :
hydrophilic
hydrophobic

12. Cut the Mustard
How you could make a salad dressing without using raw egg yolk as the emulsifier?
Powdered mustard acts as an emulsifier in the preparation of mayonnaise and salad dressings.

13. homework
After eating your mayonnaise, find out the cure for salmonella (it may be helpful)!