Food speed lesson
3 run throughs
2 Breaks
And how about eating?
• We need a healthy diet, this contains
–Carbohydrate
–Protein
–Vitamin
–Mineral
–Water
–Fat
–Fibre
Enzymes and carbohydrate digestion
Carbohydrates are chains of identical sugar molecules.
Enzymes called carbohydrases (amylases) break the chemical
bonds, making glucose molecules
carbohydrase
long
carbohydrate
molecule
sugar
molecules
5/7 is Carbohydrate
Fat; 1
Protein; 1
Carbohydrate;
5
Starch Test
• Put a sample of food in the bottom of a
test tube.
• Add a drop of iodine solution.
• What colour change will there by if
starch is present.
Glucose (From carbohydrates)
… for energy
Test for Glucose
Put a sample of your food stuff in a test tube.
Add five drops of Benedict’s solution.
Heat gently in a water bath.
Benedict’s solution will turn from
in the presence
of glucose.
•
•
•
•
Enzymes and protein digestion
Proteins are made up of different amino acids. There are 20
different types of amino acids.
Enzymes called proteases break down proteins. These enzymes
work in an acidic environment to break proteins into smaller
amino acids.
protease
long
protein molecule
amino acid
molecules
Whey PROTEIN to build muscle
Test for Protein
• Put a sample of your food
stuff in a test tube.
• Add five drops of Biuret’s
solution.
• Carefully shake the test
tube.
• Biuret’s solution will turn
from blue to purple
1/7 is Protein
Fat; 1
Protein; 1
Carbohydrate;
5
Fats
• Store energy and used
in cell membranes to
help stop water moving
through
Where do we find fats
• Fats often coat foods
• Like oil on chips
Enzymes and fat digestion
Fats are digested in two stages:
 Firstly, bile breaks fat into smaller droplets. This is called
emulsification.
bile
 Secondly, the enzyme lipase breaks each fat molecule into
the smaller glycerol fatty acid molecules .
lipase
fat molecule
+
glycerol
fatty
acids
Test for Fats
• Add Ethanol and shake
• Add distilled water
• If fat is present a milky-white emulsion
(layer is formed)
1/7 is Fat
Fat; 1
Protein; 1
Carbohydrate;
5
• Carbohydrates: Bun, Chips (Lots of the meal!)
• Protein: Meat (Not much .. 1/7th?)
• Fat: Coating the chips and meat … 1/7th?
What else?
Vitamins and Minerals
Vitamins
• Are made of many different types of elements
• Key Vitamins are C and D
• Vitamin C
– Dissolves in Water and found in fruit
– Problems of not enough include falling out teeth
• Vitamin D
– Dissolves in Fat
– Problems of not enough include soft bones
Vitamins and Minerals in the salad
Vitamin C
• To stop you losing
your teeth to scurvy
Vitamin D
• Stops rickets
• Bendy bones
Minerals
• Minerals are elements
• Key minerals are Iron and Calcium
• Iron
– Found in meats,
– used in blood.
• You could also just go and lick some iron.
• Calcium
– Found in dairy products (milk, cheese) and fish
– Used in bones, teeth, blood clotting and muscles
You need minerals and vitamins
• Iron in the blood
• To carry oxygen
No calcium can cause problems
Water Facts
• 70% of the human body
• Humans lose around 1.5 litres per day
– In urine, faeces, sweat and breathing
• Re-absorbed in drink, food AND RESPIRATION
• Losing 5% water = unconsciousness
• Losing 10% water = death
A Water saving methods
• The Kangaroo Rat
Method
• Don’t drink and absorb
all water in kidneys.
• RESPIRATION EQUATION
• Glucose+Oxygen => Energy+CO2 + WATER
Fibre
• Allows your faeces to
pass through
• Found in things you
don’t digest (think of
your faeces after eating
sweetcorn!)
• Without it you look like
this
Things can be added to food
• Food Additives
make things look
better,
Make it last longer
Even change taste
Fortifiers make food
stronger
• Iron in cereals!!!
Some things are left over.
These are residues
• They could be
hormones for
growth
Fertilizers to add minerals
Or even pesticides
• To kill bugs
Food residues
• These can also be
eaten in food.
Food problems
Too much = problems
• Rubbing joints
(arthritis)
• Type II Diabetes
– No Insulin
• Heart attacks
Too little = problems too
• The body doesn’t
eat food so it eats
itself
– Atrophy
• Hair loss
• Reduced immune
system
How to work it out
• BMI
Mass (kg)
Height x Height (m)