- Created by: ajwoolfall
- Created on: 22-01-18 12:20
- Used to identify reducing sugars (monosaccharides and some disaccharides)
- Add Benedict's solution to the chemical sample and heat.
- The solution changes from blue to brick-red yellow if a reducing sugar is present.
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Non-reducing sugar test
- Used to test for non-reducing sugars, e.g. the disaccharide, sucrose
- First a benedict's test is performed
- If the Benedict's test is negative, the sample is hydrolysed by heating with hydrochloric acid, then neutralised with sodium hydrogen carbonate.
- This breaks the glycosidic bond of the disaccharide, releasing the monomers.
- A second Benedict's test is performed which will be positive because the monomers are now free.
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- Add iodine solution to the sample.
- If starch is present the colour changes to bliue-black
All the biochemical tests need to be learned. This work is good value because they are regularly tested in 2 or 3 mark quaetion components.
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- Used to identify fats and oils
- Add ethanol to the sample, shake, then pour the mixture into water.
- If fats or oils are present then a white emulsion appears at the surface.
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- used to identify any protein
- Add dilute sodium hydroxide and dilute copper sulohate to the sample.
- A violet colour appears if a protein is present.
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