| Biology demonstration manual |
Lesson: Les ailments
Rationale: Test for the presence of proteins in food samples.
10% NaOH (available at Bangui paint stores. Ask for "soude caustique". As a solid NaOH is very hydroscopic so store in an airtight container.)
1% Copper sulfate (science kit)
needle and 5 ml syringe (for measuring; available at any pharmacy.)
eye dropper (science kit)
Suggestions for sample:
Positive: milk, peanut butter
Negative: manioc flour, banana, orange juice
Procedure: To prepare solutions:
1. 10% NaOH- 8 gm (or 1.5 tsp) of NaOH in 100 ml of filtered water.
2. 1% Copper sulfate- 1 gm (or 118 tsp) of copper sulfate in 100 mls of filtered water. It will be a very faint blue.
3. For liquids (ie., milk, orange juice) put about I ml in a clear glass. For solids (ie., peanut butter, flour, banana) mix or mash in 1 ml of water.
4. Add 1 ml of 10% NaOH and mix by swirling.
5. Add ~5 drops of 1% copper sulfate (or enough to give a nice color change.)
6. A violet color indicates the presence of proteins.
Source: Mackean Class Experiments in Biology, p. 14; Teacher's Book, p. 4, 21.