My Biology Notebook

Food Tests


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Food Tests 

- Benedicts: Test for simple sugars (monosaccharides + disaccharides), e.g., glucose, sucrose, maltose.

- Not sucrose → Add hot (boiling) water for the test. 
- Negative result: stays blue 
- Positive result: brick-red precipitate


- Iodine: Test for starch
- Negative result: stays orange
- Positive result: turns blue/black 


- Biuret: Test for proteins 
- Negative result: stays blue
- Positive result: turns lilac


- Emulsion: Test for lipids 
- Add equal amounts of ethanol and distilled water. 
- Positive result: a milky-white emulsion forms. 


- Sudan III: Test for lipids 
- Positive result: red-stained ring formed on surface of solution.

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