Food Test Practicals

Question 1

Benedic’s Test for Sugars

Answer 1

1 - Break up the foods using a pestle and motar, add to a test tube of distilled water, mix the food with a glass rod with the water, filter the mixture using filter funnel and paper, collect the solution

2 - Add 10 drops of benedicts solution to a test tube.

3 - Set up a traditional water bath at 75c, with a bunsen burner.

4 - Place the test tube in the water bath at 75c for 5 minutes - note down any colour changes which took place - green - brick red

Question 2

Test for Starch

Answer 2

Iodije

Get food sample and transfer 5cm of the sample into a test tube.

Add a few drops of iodine solution and gently shake the tube to mix the contents - should turn black or blue black

Question 3

Lipids - Sudan III test

Answer 3

Prepare a sample of the food you are testing, no need to filter it. Add 5cm to a test tube

Use a pipette and add 3 drops of Sudan III to a test tube, and gently shake.

If lipids present, the top layer will be bright red

Question 4

Protein - What test

Answer 4

Bieuret test

1 - Prepare a sample of your food and transfer 2cm of sample into a test tube

2 - Add 2cm of biuret reagent to the sample and mix the contents of the test tube by gently shaking it

If it has protein, it goes from blue to purple