Food tests

Benedict’s test

(sugars)

• 1) place food sample into a beaker containing distilled water

• 2) heat beaker in a water bath and leave it for five minutes at 75 degrees Celsius

• 3) after five minutes, add a few drops of benedict’s solution to the sample

• 4) if solution turns from blue to green a low concentration of sugar is present

• if solution turns from blue to orange a medium concentration of sugars are present

• if solution turns from blue to brick-red a high concentration of sugars are present

Iodine test

(starch)

• 1) place food sample into a beaker containing distilled water
• 2) add a few drops of iodine solution
• 3) if solution turns from orange/brick-red to blue/black then starch is present

Biuret test

(protein)

• 1) place food sample into a beaker containing distilled water
• 2) add a few drops of biuret solution to the beaker
• 3) if colour change from blue to lilac, proteins are present.