Transcript KS4 Food (D&T) - Crofton Academy

Food Technology
Smart and modern ingredients
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Learning objectives
Learning objectives
To understand what smart and modern ingredients are
and why they are used in food manufacture.
To learn about the different types of smart and modern
ingredients.
To understand about the role of microbiology and
enzymes in food manufacture.
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What are smart and modern ingredients?
Smart ingredients do not occur naturally. They have been
developed through the invention of new and improved
processes (new technology). They are natural ingredients that
have been changed in some way to behave differently (such as
a starch that thickens without being heated).
Modern ingredients are ones that have been recently
introduced because of new technology. They are natural and
have not been changed to behave differently. Probiotic
yoghurts could be described as a modern ingredient and quorn
is another one.
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Why are smart and modern ingredients used?
Smart and modern ingredients are used by food manufacturers:
to make food behave in a certain way – i.e. to keep the
sauce in a ready meal runny when cold
as an alternative ingredient – for example, as a meat
analogue or a fat replacer
to improve the nutritional content of the food – for example,
the fortification of breakfast cereals
Examples of such ingredients are artificial sweeteners,
alternative proteins, fortified foods, chemically-modified starches,
fat replacers, physically-modified starches and geneticallymodified foods.
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What are modified starches?
Starches are the biggest group of smart materials available to
food manufacturers today. These smart starches are called
modified starches. They can be chemically or physically modified:
Sauce flour is physically modified during milling so that it
does not clump together in lumps when you make a sauce.
Thickening granules are chemically-modified maize starch
which can be added to hot water without lumps being formed.
There are over 300 modified starches which are used in sauces,
meat and dairy products, salad dressings, snacks and drinks,
fruit fillings and preparations, baked products and sweets and
even pet foods and animal feeds. Very few of these starches are
available to consumers.
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Chemically-modified starches
Chemically-modified starches are the biggest range of smart
starches. They are modified by chemical treatment such as
oxidation and hydrolysis (oxygen and hydrogen atoms are
added to starch molecules) to behave in all sorts of ways.
They stay viscous (runny) when the product is chilled.
They prevent synerisis (water leaking out of the sauce) during
freezing.
They remain unaffected by acid or sugar – i.e. they do not
go runny when acid or sugar are added.
They remain stable during processing.
They have mouth feel properties during processing.
They provide a source of NSP (fibre) without the
disadvantages of using wholemeal flour.
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Physically-modified starches
Most physically-modified starches are pre-gelatinized starches.
They are pre-cooked.
Starch is heated up in liquid until it gelatinizes (thickens).
The mixture is cooled and spray-dried into tiny granules.
The granules are used in instant foods where ‘cooking’ does
not happen but where just hot or cold water is added and the
food is instantly eaten.
What foods can you think of that use this instant starch?
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What are fat replacers?
Food manufacturers use modified starches that give the texture of
fat – the rich, creamy and oily-like feel. They are fat mimetic
starches and are used in low-fat dressings, sauces, soups and
gravies as well as in ice cream, other frozen desserts and dairy
products.
There are a wide range of low-fat spreads available to the
consumer which contain less than half fat. If you look at the label,
you will see that the main ingredient is water (and air!). They
cannot be used in cooking, since the water will evaporate and the
air will disappear when heated.
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What are new protein foods?
Lots of development is going on into sources of protein that do
not involve animals, either for economic reasons or because
some people do not want to eat animal products.
New protein foods which often have less fat than meat are now
available to the consumer:
tofu
texturized vegetable protein (TVP)
quorn.
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How is quorn made?
Quorn is a mycoprotein. It is a tiny fungus that is continuously
fermented in towers as tall as Nelson’s column.
Nutrients are continuously fed into the fermentation tower. The
fermented liquid is filtered and drained off.
The fermented liquid is passed through a centrifuge to remove
the water and leave a paste.
The paste is mixed with extra ingredients, formed into different
shapes and finally steamed so that it retains the right shape.
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Properties of quorn
It has a texture similar
to chicken and breaks
down in the mouth during
chewing just like meat.
It is high in protein
and low in fat. It is a
good source of B
vitamins.
It lacks flavour
but absorbs
surrounding
flavours well.
It is not suitable for
vegans as egg white
is used in the process.
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It contains more
fibre than meat
but still only quite
a small amount.
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How are tofu and TVP made?
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Properties of textured vegetable protein (TVP)
It is used to add bulk
to food products as
it is inexpensive
compared to meat.
It is high in protein and
fibre and low in fat (it
has a high biological value).
It can be high in sodium.
It is fortified with
vitamin B and iron.
It has a very bland flavour but
flavourings can be added
to it or it can be cooked with
distinctive flavoured foods.
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It can be dried,
frozen or chilled.
It can be extruded
to resemble the
shape and texture
of meat.
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Properties of tofu
It is a soft semi-solid food
and has a smooth texture.
It can be plain,
marinaded or
smoked.
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It is high in
protein and quite
high in fat.
It is also available in
‘silken’ form to replace
cream cheese or yoghurt
in desserts, sauces or dips.
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New protein foods quiz
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What is fortification?
In the past, fortification was used to prevent or treat a nutrient
deficiency or illness – for example, iodine was added to salt to
prevent goitre and vitamin D was added to milk to prevent rickets.
Today, fortification is used to replace nutrients lost during
processing and to optimize health.
White flour is fortified with B vitamins since these are lost
during processing. It is given the same vitamin B content as
found in wholemeal flour.
Vitamins A and D are added to margarine so that it has a
similar nutritional profile to butter.
A lot of products (breakfast cereals, drinks, biscuits and cereal
bars) are fortified with a range of different nutrients.
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Fortified products
Columbus eggs are special eggs that contain more of the fatty
acid, Omega 3, than ordinary eggs. Most people do not get
enough Omega 3 which is essential for a healthy heart (oily fish
such as mackerel is also a good source of Omega 3). The hens
that lay Columbus eggs are fed on lots of seeds and greens –
similar to the natural diet of wild fowl years and years ago. The
yolks of Columbus eggs contain less saturated fat, more
polyunsaturated fat and a lot more Omega 3 in comparison to
normal eggs.
Fibre-rich white bread contains a modified starch which is
resistant to being broken down into glucose in the stomach. The
starch is called novolose and is only available to food
manufacturers. It can be used in all sorts of baked products,
snacks, cereals and even drinks!
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What are probiotic products?
Probiotic products have been made available by new technology
and claim to contain ‘friendly’ bacteria which help with
digestion. 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.
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What are sweeteners?
Sweeteners are additives but also smart ingredients. They have
been created by technologists to fulfill a new purpose:
Intense sweeteners such as saccharin are 300 – 500 times
sweeter than sugar weight for weight.
Some food products also need the bulk which sugar provides so
a bulk sweetener such as sorbitol is used. Sorbitol has reduced
calories but does brown when heated.
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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 alter the
genetic make-up of cells to change their
properties.
For example, a crop wheat could be made
more resistant to disease by transferring
certain characteristics from wild wheat.
Life savers or Frankenstein foods? You decide.
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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 fuels used and to help the
environment.
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Genetically-modified enzymes
Enzymes are proteins which speed up chemical reactions such
as digesting food.
Chymosin is an enzyme extracted from the stomach of calves
and 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 which
is produced is suitable for
vegetarians and as a result
fewer calves are slaughtered.
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So, it’s a good thing then?
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Smart and modern ingredients quiz
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Key points
Key points
Smart and modern ingredients are used by food
manufacturers as an alternative ingredient; they
are also used to make food behave in a certain
way and to improve the nutritional content of
food.
There are many different types of smart and
modern ingredients: modified starches, fat
replacers, new protein foods, fortified and
probiotic products, artificial sweeteners and
GM foods.
There are many advantages to GM foods as
well as many disadvantages.
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