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Testing for carbohydrates

Simple tests can detect the presence of proteins, lipids and carbohydrates in given samples (i.e. various food items). Testing for carbohydrates. Lugol's reagent (iodine solution) Benedict's solution. Testing for the presence of starch (complex sugar).

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Testing for carbohydrates

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  1. Simple tests can detect the presence of proteins, lipids and carbohydrates in given samples (i.e. various food items)

  2. Testing for carbohydrates • Lugol's reagent (iodine solution) • Benedict's solution

  3. Testing for the presence of starch (complex sugar) Lugol's reagent (iodine solution) changes from yellowish-brown to dark purple/black.

  4. Testing for simple carbohydrates When Benedict's solution and simple carbohydrates are heated, the solution changes to orange red/ brick red.

  5. Testing for lipids Grease spot test/Brown paper test Sudan Red test

  6. Brown paper test for lipids As we all know from experience, lipids leave translucent spots (grease spots) on unglazed brown paper bags.

  7. Sudan Red test for lipids Sudan red is a fat-soluble dye that stains lipids red. Using Sudan red can show the amount and the location of lipids.

  8. Testing for proteins –Biuret test Biuret solution is a blue liquid that changes to purple when proteins are present and to pink in the presence of short chains of polypeptides. The copper atom of the biuret solution reacts with the peptide bonds to cause the color change.

  9. Testing for proteins – Buiret test

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