Transcript Modern Food Materials

Modern Food Materials
These icons indicate that detailed teacher’s notes or useful web addresses are available in the
Notes Page.
icon indicates
the slide contains
Flash.
These activities
are not editable.
This iconThis
indicates
the slide contains
activities activities
created increated
Flash. in
These
activities
are not editable.
For more
detailed
instructions,
see the Getting Started presentation.
For more detailed instructions,
see the
Getting
Started presentation.
1 of 18
© Boardworks Ltd 2004
Modern food materials
Food companies spend millions of pounds each year
developing new food products.
Food science can make
food that is better for the
people who eat it.
Leave our food
alone, you're only in
it for the money.
Let's look at some examples to help you decide what
you think.
2 of 18
© Boardworks Ltd 2004
New protein foods
Lots of development is going on into sources of protein
that don’t involve animals, either for economic reasons or
because some people do not want to eat animal products.
New protein foods, like tofu, texturized vegetable protein
and Quorn are often lower in fat than meat, and a good
source of protein.
3 of 18
© Boardworks Ltd 2004
New protein foods
4 of 18
© Boardworks Ltd 2004
Probiotic products
Whilst some bacteria can make us ill, other can help us
digest our food.
Probiotic products claim to contain ‘friendly bacteria’
which will help us digest our food better.
They are often supplied as yoghurts and drinks.
There are lots of beneficial health claims
made by probiotic food companies.
However, more research still needs
to be done to prove some of the claims.
5 of 18
© Boardworks Ltd 2004
Preservatives
6 of 18
© Boardworks Ltd 2004
Phytochemicals – chemicals from plants
Phytochemicals are
biologically active nutrients.
They occur naturally in fruit
and vegetables giving them
their scent, flavour and
colour.
Research shows they may
also be useful in protecting
against diseases like
cancer and heart disease.
7 of 18
© Boardworks Ltd 2004
Antioxidants – what are they?
Antioxidants stop substances in foods from combining
with oxygen.
When oils and fats oxidise they become rancid. They
smell and taste unpleasant and are a health risk.
Vitamins C and E are antioxidants that occur naturally,
and so is beta carotene. Other antioxidants are man
made.
Antioxidants are examples of phytochemicals.
Vitamin C is found in green leafy vegetables,
like these cabbages, potatoes, citrus fruits,
strawberries, peppers and tomatoes.
8 of 18
© Boardworks Ltd 2004
Antioxidants – why are they useful?
Oxidation is linked to the aging process, like the
formation of wrinkles.
It is also involved in some diseases such as arthritis,
cancer and cataracts.
Free radicals formed by oxidation make cholesterol
sticky, and then it can block arteries.
Eating lots of fruit and vegetables will give you natural
antioxidants.
Adding antioxidants to other foods may also help fight
these diseases.
9 of 18
© Boardworks Ltd 2004
Modified starches
Modified starches are normal starches
that have been altered chemically or
physically in some way.
Starches have always been used to
thicken foods, for instance corn flour is
used to set flavoured milk to make a
blancmange. When milk is heated to
boiling point, the starch grains swell and
the blancmange thickens.
Granular starches have now been
developed that swell in cold water, and so
can be used to set desserts instantly.
10 of 18
© Boardworks Ltd 2004
Other uses of modified starches
Oxidised starches produce tough, clear films that make
products like fish coatings and french fries crispier.
They are also added to some breakfast cereals so they
stay crisp after you add the milk.
Re-dried starches have less moisture than ordinary ones
and are used to dust sweet moulds to stop the sweets
sticking.
Modified starches are also used
in many low fat products. They
improve the melting and stretching
of imitation mozzarella cheese and
also its flavour.
11 of 18
Mozzarella
Or Modified
Starch?
© Boardworks Ltd 2004
Genetically
modified foods
Life savers or Frankenstein foods? You decide.
12 of 18
© Boardworks Ltd 2004
What are GM foods?
All living things are made up of genetic material.
Nature has always changed the genetic properties of
living things by mutation and natural selection.
Now modern scientists can change the
genetic make up of cells to change their
properties.
For example, genetic engineering could
allow certain characteristics of wild wheat
to be transferred to wheat grown as a
crop to make it more resistant to disease.
13 of 18
© Boardworks Ltd 2004
How are foods genetically modified?
Scientists use chemical ‘scissors’ to obtain the DNA or
gene they want to transfer. It could come from an
animal, a plant or bacteria.
They then place it into a plant cell.
The DNA then gets into the nucleus of the plant, and
new cells grow from the altered ones to make plants
with the new characteristics.
The DNA will have been chosen to pass on the feature
they want the new plant to have.
Gene taken from
bacterium that
produces a natural
insecticide
14 of 18
Added to wheat cells
Wheat that does not
need to be sprayed
against insects
© Boardworks Ltd 2004
Why are foods genetically modified?
Some genetic engineering is done for economic
reasons – the crop will grow bigger or faster and so
make more money.
GM crops may be useful to poorer countries if they need
less water, or are more resistant to pests and diseases.
Some genetic research is for medical developments
such as new vaccines or cancer treatments.
It may be possible to make biodegradable plastics
from plants to reduce the amount of fossil fuel we use
and help the environment.
Tomatoes, modified to contain
three times the normal amount of
vitamin A, may help prevent
cancer, scientists claim.
15 of 18
© Boardworks Ltd 2004
Genetically modified enzymes
Enzymes are proteins that speed up chemical
reactions such as digesting food.
Chymosin is an enzyme extracted from the
stomach of calves which is added to milk as rennet
to make cheese.
An equivalent enzyme can be made from
genetically modified micro-organisms such as
yeast.
This means the cheese that
is produced is suitable for
vegetarians and as a result
fewer calves are slaughtered.
16 of 18
© Boardworks Ltd 2004
So it’s a good thing then?
17 of 18
© Boardworks Ltd 2004
Summary
18 of 18
© Boardworks Ltd 2004