Transcript KS4 Food (D&T) - Crofton Academy

Food Technology
Additives
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Learning objectives
Learning objectives
To understand what additives are.
To understand the role of additives in food production.
To know what the beneficial and detrimental effects of
additives are.
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Ingredients in traditional ice cream
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How is traditional ice cream made?
Sugar is dissolved in
water over heat and
boiled to a light syrup.
The mixture is poured into an ice
cream machine and churned until
frozen or put in a freezer and
whisked every 2 hours until
frozen (so large ice crystals do
not form).
Egg yolks are whisked while
the hot syrup is slowly poured
in. The mixture is whisked until
it is thick and like a mousse.
The cream is
whisked in.
Could this kind of ice cream be made in large quantities?
Are the ingredients expensive?
Is it safe to use raw eggs and cream?
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Ingredients in manufactured ice cream
Manufactured ice cream contains the following ingredients:
partially reconstituted lactose reduced
whey protein concentrate
sugar
hydrogenated vegetable oil
dextrose
whey powder
What do you
emulsifiers
think of the
stabilizers
ingredients
flavourings
used?
and colours.
The last four ingredients are additives which is nearly half the
ingredients!
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What are additives?
Additives are synthetic or natural substances which are added to
food in small quantities. They have a number of different
functions such as:
preventing spoilage and prolonging a food’s shelf life
improving or enhancing a food’s flavour or appearance
helping the processing and preparation of food and ensuring a
consistent quality of food
restoring the food’s original characteristics after processing
maintaining or increasing the food’s nutritional value
allowing a bigger variety of food products to be produced and
in particular, quick and easy convenient foods.
Why are additives used in ice cream?
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What is in manufactured ice cream?
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Emulsifiers and stabilizers
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Emulsifiers and stabilizers
What are emulsifiers and stabilizers?
Emulsifiers give foods a smooth creamy
texture and help substances such as oil
and water to mix together, form an
emulsion and stay mixed. They are found
naturally in eggs so real ice cream does
not need any added emulsifier.
Stabilizers help emulsifiers work –
they stabilize the emulsion. In ice
cream they control the texture. If
the ice cream partially melts on the
way home from the shop, the
stabilizer will help it to maintain the
same texture and stop it freezing
back into a block of solid ice.
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Flavours
Flavour is the essence of food. It comes from the combined taste
and aroma of food. There are five basic flavours (sweet, sour,
bitter, salt and savoury) which combine to create all the food
flavours we know. Flavours are:
natural such as herbs and spices
natural identical (made in a laboratory
but chemically the same as certain
natural products
artificial (man-made but not found in
nature).
The flavour used in a lot of ice cream is
vanillin – a natural identical flavour taken
from vanilla.
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Flavour enhancer: monosodium glutamate
Monosodium glutamate or MSG makes the tongue more
receptive to savoury salty tastes. It is usually manufactured from
wheat gluten or beet molasses by a fermentation process
devised in the 1950s. It is the sodium salt of glutamic acid.
MSG is used in these
economy burgers (less than
60p for 8 burgers!) to give
them a meaty taste. The actual
meat content is just over 50%
– meat is an expensive
ingredient. It is also used in
cheese sauces to make them
taste cheesy – cheese is
another expensive ingredient.
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Colours
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Making orange squash
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Preservatives
Preservatives increase the shelf life of foods by preventing the
growth of bacteria. Salting, drying, pickling, heating, chilling
and freezing are methods of preservation as well as using
chemical preservatives.
The use of chemical preservatives is really a continuation of
age-old practices of using salt and spices to preserve foods.
Most chemical preservatives are closely related to natural
substances. For example, E210 Benzoic acid occurs in several
fruits such as the Scandinavian cloudberry. Sorbic acid is found
in some plants such as the mountain ash. E234 Nisin occurs in
milk and cheese.
By adding preservatives to food, consumers can shop less
frequently and bulk buy.
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Antioxidants
Antioxidants prevent food containing fat from going rancid – they
stop the fat from reacting with the oxygen in air. They also
prevent the oxidization of fruit and vegetables – stop them from
going brown.
The most powerful antioxidant is ascorbic acid (E300) which is
found in a lot of fruit, especially citrus fruit. Ascorbic acid is
another name for vitamin C, so it has nutritive properties as well.
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Sweeteners
Sugar provides sweetness, quick energy and calories.
Sweeteners provide sweetness without the calories. There are
two types of sweeteners – bulk and intense.
Sorbitol (E420) is a bulk
sweetener which provides
the bulk, texture and
sweetness of sugar but with
reduced calories. Like sugar,
it does not brown when
heated. Unlike sugar, it does
not need insulin to break it
down in the body and so can
We are a sweet-tooth society!
be eaten by diabetics.
Saccharin is an intense sweetener. It is 300 - 500
times sweeter than sugar weight for weight.
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Other additives
Other additives include:
raising agents such as sodium bicarbonate which give a
lighter texture to baked products
anti-caking agents which stop crystals and powders like salt,
cocoa and even parmesan cheese from sticking together
thickening agents (gums or modified starches) which form a
gel and thicken sauces
propellants used in aerosol products such as cream or oil
nutrients – usually vitamins and minerals – which are added
to replace nutrients lost during processing or to enrich certain
foods. Vitamins A and D are added to margarine so that it has
a nutritional profile similar to butter.
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Additives word search
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Are additives good or bad?
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Key points
Key points
Additives are non-nutrient materials which are
added to food in very small quantities.
Additives can be natural, natural identical or
artificial.
Using additives in food means that a wider
variety of food products can be made with
better colour, flavour and texture. They also last
longer.
Some consumers are concerned about the
effects of eating additives.
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