biological molecular
Objective:
1) To test the presence of reducing sugars which is glucose in the Benedict's test.
2) To test the presence of non-reducing sugars which is sucrose by using Hydrolysis then Benedict's test.
3) To test the presence of the starch by using iodine test.
4) To test the presence of lipids in corn oils when using the Sudan Ш and Emulsion tests.
5) To test the presence of proteins in an egg albumen in the Biuret's test.
6) To test the presence of Vitamin C and ascorbic acid in the DCPIP test.
Results:
Figure 1 :Results of biochemical test for different food samples in test tubes
In test tube A, the Benedict's test is used to test for the presence of reducing sugar which is glucose.This test gives the positive result and the colour changes of the solution is from blue solution to brick-red precipitate.
In test tube B, the Hydrolysis then Benedict's test is tested for the non-reducing sugar which is sucrose. After boiling the solution of sucrose and dilute hydrochloric acid, the solution is neutralised with sodium hydrogen carbonate and after that the Benedict's test is tested. This final result is positive and the colour change from blue to brick-red precipitate.
In test tube C, the iodine test is tested for the presence of starch. This test gives the positive results and the colour change from brownish-yellow to blue-black.
In test tube D, the presence of lipids in corn oil is tested by using the Sudan Ш and Emulsion tests. When testing the Emulsion test, a mixture of corn oil and ethanol form a cloudy white suspension. After that, the milky white suspension is separated with the oil droplets. The milky white suspension will remain at the bottom of test tube and the oil droplets will form the top layer of the solution when distilled water is added. Then, the solution will form a red-stained layer which separates on the surface of the solution when Sudan Ш is added.
In test tube E, Biuret's test is tested for the presence of
1) To test the presence of reducing sugars which is glucose in the Benedict's test.
2) To test the presence of non-reducing sugars which is sucrose by using Hydrolysis then Benedict's test.
3) To test the presence of the starch by using iodine test.
4) To test the presence of lipids in corn oils when using the Sudan Ш and Emulsion tests.
5) To test the presence of proteins in an egg albumen in the Biuret's test.
6) To test the presence of Vitamin C and ascorbic acid in the DCPIP test.
Results:
Figure 1 :Results of biochemical test for different food samples in test tubes
In test tube A, the Benedict's test is used to test for the presence of reducing sugar which is glucose.This test gives the positive result and the colour changes of the solution is from blue solution to brick-red precipitate.
In test tube B, the Hydrolysis then Benedict's test is tested for the non-reducing sugar which is sucrose. After boiling the solution of sucrose and dilute hydrochloric acid, the solution is neutralised with sodium hydrogen carbonate and after that the Benedict's test is tested. This final result is positive and the colour change from blue to brick-red precipitate.
In test tube C, the iodine test is tested for the presence of starch. This test gives the positive results and the colour change from brownish-yellow to blue-black.
In test tube D, the presence of lipids in corn oil is tested by using the Sudan Ш and Emulsion tests. When testing the Emulsion test, a mixture of corn oil and ethanol form a cloudy white suspension. After that, the milky white suspension is separated with the oil droplets. The milky white suspension will remain at the bottom of test tube and the oil droplets will form the top layer of the solution when distilled water is added. Then, the solution will form a red-stained layer which separates on the surface of the solution when Sudan Ш is added.
In test tube E, Biuret's test is tested for the presence of