Mandatory experiments on Food

1. Mandatory experiments on Food

2. Test for reducing sugar

5. Test for fats

9. Test for protein

12. Test for starch

16. Food Tests – Summary Chart

17. Experiment Questions Food Tests

18. Food Tests For what is the Biuret test (copper sulphate and sodium hydroxide solutions) used in the biology laboratory? Test for protein

19. Food Tests For what is the Benedict’s (or Fehling’s) test used in the biology laboratory? Test for reducing sugar

20. Food Tests For what purpose did you use brown paper or Sudan III in food testing? To test for Fat / Lipid / Oil

21. Food Tests What reagent or chemicals did you use to test for protein? Biuret OR NaOH and CuSO4

22. Food Tests Is heat necessary in the test that you carried out to test for protein? No

23. Food Tests What colour change indicates the presence of protein? From blue to purple / violet

24. Food Tests Name the test or name the chemical used to test a solution for the presence of glucose (reducing sugar). Clinistix / Benedicts / Fehling’s / Copper sulphate

25. Food Tests What colour change indicates a positive result for the presence of glucose? (Clinistix) Orange to Blue or (others) Blue to Red

26. Food Tests Is heat necessary to test a solution for the presence of reducing sugar? Yes

27. Food Tests For which purpose did you use Biuret solution or alkaline copper sulphate in food testing? To test for (soluble) protein

28. Food Tests State a use for the Biuret test in the biology laboratory. To detect presence of protein

29. Food Tests What is the initial colour of the reagent or chemicals used to test for protein? Blue

30. Food Tests Was there a colour change in the control experiment when testing for protein? No

31. Food Tests Name the test or give the chemicals used to test a sports drink for the presence of protein. Biuret Test / Sodium Hydroxide & Copper sulphate

32. Food Tests If protein is present in a drink, what colour change would you expect to see? In your answer give the initial and final colour of the test solution. Blue to violet /purple / lilac

33. Food Tests Is heat necessary for the test for protein? No

34. Food Tests For what purpose did you use Fehling’s solution or Benedict’s solution in the course of your practical activities? To check for Glucose / reducing sugar

35. Food Tests For which purpose did you use Brown paper or Sudan III in food testing? To test for fat (or lipid or oil)

36. Food Tests—Reducing sugar (i) Name the reagent(s) used. (ii) State the initial colour of the reagent. (i) Benedict’s/ Fehlings I and II, (ii) Blue

37. Food Tests—Reducing sugar State whether the test requires heat. Yes

38. Food Tests—Reducing sugar What colour indicates a positive result? Brick-red/orange

39. Food Tests—Protein (i) Name the reagent(s) used. (ii) State the initial colour of the reagent. (i) Biuret solution / CuSO4 + NaOH (ii) Blue/ light blue

40. Food Tests—Protein State whether the test requires heat. No

41. Food Tests—Protein What colour indicates a positive result? Purple / violet

42. Food Tests (i) Name a test to show the presence of a reducing sugar (e.g. glucose). (ii) Describe how you would carry out this test. (i) Benedict’s/ Fehling’s (ii) Dissolve sample in water or put in test tube / add reagent / heat / don’t boil / observe change or state result (brick-red-orange precipitate)

43. Food Tests (i) Name a test for protein. (ii) Describe how you would carry out this test. (i) Biuret test or named chemicals (ii) Add biuret reagent (or sodium hydroxide and copper sulfate) / to sample / heat or shake / observe or record colour change (purple-violet)

44. Questions pg 13/14