8/8/2019 Nutrients Lab
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LAB SESSION NUMBER 4
TITLE: Nutrients in FoodsBackground Reading -Biology by N.
Campbell and J. Reece. 6 th Edition, chapter
7.
Table Showing Tests For the Identification of Biochemicals
Test ProcedureIodine/Potassium Iodide test Add two drops I 2/KI
on a food sample and observe.
Benedicts test Add 2 cm 3 of solution to a test tube and add
equal volume of Benedicts solution. Shake and bring to a gentle
boil.
Benedicts NRS test Add 2 cm 3 of solution to a test tube. Add 1
cm 3 dilutehydrochloric acid. Boil for one minute. Carefully
neutralizewith a base (see lab #3). Carry out Benedicts test.
Emulsion test Add 2 cm 3 of solution to a test tube containing 2
cm 3 of absoluteethanol. Shake vigorously and then add equal volume
of coldwater.
Grease spot test Rub a sample of a solid food or liquid food on
brown paper.Hold the paper to the light and observe.
Biuret test Add 2 cm 3 of protein solution to a test tube. Add
an equalvolume of 5 % potassium hydroxide solution and mix. Add
2drops of 1% copper sulphate solution and mix.
Construct a table to show results.
Table Showing..FoodNutrient
Name of Test
ExpectedPositiveResult
Observation (any 3 food samples)
Milk Bread MeatSimpl e Sugar This must include step by step
observation of what is
seen. NR Sugar StarchFatProtein
Procedure #2
Test for SugarsUsing the appropriate test identify solutions A,
B, and C as either R.S. or N.R.S. Give detailedobservations for
your identification results by writing the sequence of thinking
steps used toidentify solutions A, B, and C. Analyse your results
and state your conclusions.
8/8/2019 Nutrients Lab
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Test for proteinUsing the appropriate test quantitatively,
determine which sample (X or Y) has more protein.
Problem 1 : Mr. Charles comes form overseas and claims that he
has a miracle energy drink
called Q. You are given substance Q. It is a clear liquid and it
does not test positive for any carbohydrates, fats or proteins.
What do you think ?Problem 2 : Donna wants to lose weight and she
asks, Which has more calories vegetable oil
or honey?What could you do to find this out and what would be
the correct answer?Explain.
Questions to Consider1. Why do you think milk has long been the
almost perfect food?2. Give the name of another test not mentioned
that could be used to test for lipids.3a. What is the test for
ascorbic acid called?
3b. What is another name for ascorbic acid?3b. What is the
procedure (3a)?3c. How could you determine the concentration of
ascorbic acid in an unknown sample of
Homestyle box drink? Explain and also give the formula.1. How
could you use this data gathered in the lab and what you have
gathered from this
exercise tohelp you plan a balanced meal?
(Answer these questions thoroughly)
NOTE: Your discussion must explain your observations and include
the basis of the test applied and any
necessary inferences (i.e. Cu 2+ +e - Cu 3+ is oxidation, blue
Cu 2+ crystals to red copper oxide
etc.)
