Download food groups and tests

L.I: To understand the major food groups our
bodies need to digest and to carry out food
tests
• THINK:
• What is digestion?
• What do we need to digest our food?
The digestive system
• Food must be digested before our
bodies can use it.
• DIGESTION means breaking down
large, insoluble molecules of food into
smaller, soluble molecules. This takes
place in our digestive system, which
runs from the mouth to the anus.
Carbohydrates - are
energy foods
Fats – store energy
Vitamins & Minerals – keep our bodies
healthy
Proteins – used for
growth and repair
Fibre – keeps food moving through
our system
Substance
Sugar Solution
Chemical test
Benedict’s
solution
Starch Solution
Protein solution
Fat – Method 1
Fat – Method 2
Result
When the Benedict's reagent was
placed in the sugar solution and
heated it turned _____.
Iodine
When the Iodine was placed into the
starch solution it turned _____
______.
Biuret
Solution
When the Biuret solution was placed
into the protein solution it turned
________.
Translucent Fat
Test
Water and
Ethanol
When the butter was rubbed on the
filter paper, the paper became
translucent as a ______ _____
appeared on the paper.
When the cheese was placed into the
water and ethanol solution, the test
tube became _____.
Testing for Starch
• You will need: iodine solution, starch solution, test
tube and a test tube rack .
1. Fill one quarter (¼) of a test tube with starch
solution.
2. Add a few (3- 4) drops of iodine into the test tube.
(WARNING: THIS MAY STAIN SO AVOID
SPILLAGES)
3. Record on your worksheet using the words provided
what colour the solution in the test tube turns.
4. Pour the iodine down the sink. Wash away any excess
black liquid that is in the sink as it will stain.
Testing for Protein
• You will need: Biuret solution, protein
solution, test tube and a test tube rack .
1. Fill one quarter (¼) of a test tube with
protein solution.
2. Add a few drops (3 - 4) of Biuret solution into
the test tube. (WARNING: THIS MAY
STAIN).
3. Shake the test tube and leave for 2 minutes.
4. Record on your worksheet using the words
provided what colour the solution in the test
tube turns.
Fat method 1 – Translucent spot test
• You will need: 1 sheet of filter paper, 1 small
cube of butter and 1 paper towel
1. Collect the butter in a paper towel using a
spatula and bring back to your desk.
2. Using your fingers, rub the butter into the
filter paper.
3. Hold the paper up the light, and record on
your worksheet in your table what has
happened to the paper.
Substance
Sugar Solution
Chemical test
Benedict’s
solution
Starch Solution
Protein solution
Fat – Method 1
Fat – Method 2
Result
When the Benedict's reagent was
placed in the sugar solution and
heated it turned _____.
orange
Iodine
When the Iodine was placed into the
starch solution it turned _____
blue
black
______.
Biuret
Solution
When the Biuret solution was placed
into the protein solution it turned
lilac
________.
Translucent Fat
Test
Water and
Ethanol
When the butter was rubbed on the
filter paper, the paper became
translucent as a ______
_____
clear spot
appeared on the paper.
When the cheese was placed into the
water and ethanol solution, the test
cloudy
tube became _____.
4 food samples were tested can you
identify what food group they belong too?
SAMPLE
IODINE
BIRUET
SOLUTION
BENEDICT’S
SOLUTION
TRANSLUCENT
SPOT TEST
WATER &
ETHANOL
A





B





C





D





Can you identify the food group?
starch
• Sample A could contain __________
because Iodine
test showed positive results.
sugar
• Sample B could contain __________
because the
Benedict’s reagent shows positive results.
protein
• Sample C could contain__________
because the
Biuret solution showed positive results.
fat
• Sample D could contain __________
because both
the translucent and water and ethanol test showed
positive results.
What you have learnt today.
• I can name the major food groups and
explain why we need them.
• I know the tests used to carry out food
tests.