Key Stage 3
Meaning
Lipids are molecules found in fats and oils.
About Lipids
- Oil is better for us than fat, but we need some of both.
- If we eat too much fat and oil then we can become obese.
These foods contain a lot of fats and oils.
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| Meat contains useful fat for our diets, but too much can lead to heart disease.
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Fish is a very healthy source of oils in our diet.
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Nuts are a healthy source of oils.
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Butter is full of fat and we shouldn't eat too much. Butter is found in cakes and cookies.
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Cooking oil is used to fry our food causing it to have a lot of oil inside it. A small amount is healthy but too much is bad for us.
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Testing For Lipids
- Adding lipids to paper can turn the paper translucent.
The Paper Test Method
- 1. Take a small sample of food.
- 2. Wipe it on a piece of paper.
- 3. Hold the paper up to the light.
- 4. If the paper has turned translucent the food contained lipids.
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| There are two patches where fat has been asborbed by the paper.
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The Alcohol Emulsion Test Method
- 1. Take a small sample of food.
- 2. Place the food in ethanol and mix by shaking or stirring.
- 3. Filter the mixture.
- 4. Add the clear solution to some water.
- 5. If lipids are present then a white emulsion will appear.
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| The mixture on the right shows the presence of lipids.
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