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Food tests
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Created by
Daniyal Zaman
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Cards (28)
What should you be able to describe by the end of the video?
How to carry out
chemical tests
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Why must safety goggles be worn during the tests?
Because all
chemicals
are
potentially
hazardous
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What are the key things to learn for the tests?
Chemicals
used for each
food group
Positive results
of the tests
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What is the first step in preparing a food sample for testing?
Grind the food with
distilled water
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What is the purpose of filtering the solution?
To remove
suspended
food particles
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What do carbohydrates include?
Starch
and sugars like
glucose
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How do you test for starch in a food sample?
Add
iodine solution
to the food solution
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What color does iodine turn if starch is present?
Blue-black
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What color is Benedict solution before testing?
Blue
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What indicates the presence of sugar in the Benedict test?
Color change
of the solution
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What does a green color in the Benedict test indicate?
A small
amount of sugar
is present
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What does a brick red color in the Benedict test indicate?
A lot of sugar
is present
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What type of sugars does the Benedict test work for?
Reducing sugars
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What color does the Biuret solution turn if protein is present?
Purple
or lilac
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How do you test for lipids in a food sample?
Add
distilled water
and
ethanol
, then shake
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What indicates the presence of lipids in the test?
A white cloudy
emulsion
forms
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Why do we not filter the solution when testing for lipids?
Lipid molecules can stick to
filter paper
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Why is ethanol considered hazardous during the lipid test?
It is highly
flammable
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What should be avoided when using ethanol in tests?
No
naked flames
should be present
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Where can you find questions on testing for chemicals in foods?
In the
vision workbook
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What is the procedure for grinding food samples with distilled water?
Use a
mortar and pestle
to make a paste
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Why is it important to stir the solution after adding distilled water?
To ensure
chemicals
dissolve properly
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What specific volumes of chemicals are used in the tests?
2
cm cubed
for most tests
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What does the color change in the Benedict test signify?
It indicates the amount of
sugar
present
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What is the distinction between reducing and non-reducing sugars?
Reducing sugars react in the
Benedict
test
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How do you prepare the Biuret test for proteins?
Add
Biuret solution
to the food solution
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Why do we not filter the lipid test solution?
Lipids can stick to
filter paper
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What safety precautions should be taken when handling ethanol?
Avoid
naked flames
around ethanol
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