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Date:

Activity 6.1 Nutrient Content in Different Food Samples

Aim

Materials Benedicts solution, dilute hydrochloric acid, sodium bicarbonate powder, starch suspension,Millons reagent, filter paper, distilled water, grape juice, carrot juice, potato, peanuts, bread,cooking oil, boiled egg white and sucrose solution.

Apparatus Test tubes, test tube holder, beaker, measuring cylinder (5 ml), white tile, tripod stand, Bunsenburner, wire gauze, mortar and pestle.

Procedure 1. Carry out food test on various food samples according to the steps listed in the observationcolumn.

Solid foods should be crushed using a mortar and pestle. Then, mix it well withwater to extract the soluble products.

2. Record all your observation.

Method 1. Food tests on various food samples were carried out.2. Observations made were recorded.

Observation Experiment Food sample Observation

A Test for reducing sugar Grape juice1. Put 1 ml of grape juice and 1 ml of Benedicts

solution in a test tube.

2. Heat it in a water bath. Carrot juice

3. Record any change in the mixture. Egg white

4. Repeat steps 1 to 3 using carrot juice, boiledegg white and sucrose solution.

Sucrosesolution

B Test for non-reducing sugar1. Put 1 ml of sucrose solution and a few drops

of dilute hydrochloric acid in a test tube.Sucrosesolution

2. Heat the mixture in a water bath for 5minutes.

Bread

3. Cool it under running water.

4. Add sodium bicarbonate until there is noeffervescence.

Egg white

5. Carry out Benedicts test. Record yourobservation.

6. Repeat steps 1 to 5 using bread and eggwhite.

C Test for starch Bread

1. Put a few drops of iodine solution on a pieceof bread. Observe the colour.

Potato

2. Repeat step 1 using potato and groundnut. Groundnut

D Test for protein1. Add a few drops of Millons reagent to

groundnut suspension.Groundnut

2. Heat it in a water bath. Bread

3. Observe for any change. Potato

4. Repeat steps 1 to 3 using bread, potato andegg white.

Egg white

E Test for lipid1. Press a few pieces of crushed groundnut on

to a piece of filter paper.

Groundnut

2. Leave the filter paper to dry. Cooking oil

3. Hold the filter paper against the light. Notefor a translucent mark.

Grape juice

4. Repeat steps 1 to 3 using cooking oil, grapejuice and crushed potato.

Potato

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Discussion 1. What is the end product obtained when carrying out Benedicts test?

2. Explain the chemical process involved in production of the end product mentioned inQuestion 1.

3. To test for non-reducing sugar, why must the food sample be heated with dilute

hydrochloric acid?

4. What is the function of sodium bicarbonate in the test for non-reducing sugar?

5. Why must the test for reducing sugar be carried out before testing for non-reducing sugarin any food sample?

Conclusion