Transcript additives - STEM Learning

WHAT:
 To learn how to
CLASSIFY
additives
according to
their properties
HOW:
• Watching a video
• Looking at the key
properties that I
need to focus on
for the
specification
• Answering some
questions
WHY:
To be able to
answer an exam
question
effectively
EXPERT
Sample Question:Explain, with an example of
each, the function of
preservatives and flavour
enhancers.
Evaluate how
additives are used,
suggest
replacement
ingredients in food
products
ASPIRE
(4 marks)
Analyse the
reasons why
additives are
used in food
products
Food Additives Specification
CHALLENGE
Cholesterol lowering spreads, fortification,
fortified foods, positive and negative effects of
colourings, emulsifiers, stabilisers, flavourings,
preservatives
Categorise the
different food
additives
 Additives
provide functional properties in
foods.
 This can be to give physical, sensory, storage
or nutritional characteristics.
 Additives may be used to satisfy more than
one of the above functions.
 i.e vitamin C is used as a vitamin and for its
antioxidant properties.
 Additives
prefixed by an “E” are approved by
the EU.
 Additives can be either natural or synthetic.
The ingredients work with the body by partially blocking the entry of
cholesterol into the bloodstream. It is claimed they lower bad cholesterol,
known as LDL, by up to 15 per cent when used every day as part of a
healthy diet and lifestyle
 An
additive might be used to make a product
:



Thicker and gelled
Made more or less acid
Aerated with gas bubbles
Emulsified
 Hydrocolloids
are substances capable of
holding large quantities of water in their
structure or joined to their molecules.
 Many substances have these properties,
carbohydrates such as starch, pectin, many
gums and gelatin are examples.
 The main sources of starch are maize and
wheat.
 It
is possible to breed different ratios of the two
starch compounds amylopectin and amylose.
 This can speed up the gelatinisation process.
 Unmodified starches can hydrate and swell rapidly
but then lose viscosity(thickness) on standing.
 Starches can be modified to improve thickening,
binding, stability, gelling and mouthfeel.
 This
is gelatinised by heating with water and
then spray dried.
 The powder produced will produce a starch
gel instantly when cold water is added.
 This is useful in the
production of cold desserts.
A
number of gums have useful thickening and
gelling properties.
 These include alginates, celluloses, xanthan,
pectins, carrageenans and tree gums such as
arabic (acacia).
 All will thicken products, some will stabilize
products to prevent oil separation.

Eg salad dressings, thickening, quick whipping
properties, milk shakes, mouthfeel.
Name
Derived From
Examples of Uses
Alginates
Brown seaweed
Thickening sauces, syrups, cake mixes,
pie fillings, canned meat, soup ice
cream, whipped cream, gel formation
of cold desserts
Xanthan Gum
A Polysaccharide
formed on the
bacterium
xanthomonas
campestris
Cold desserts, mouthfeel, viscosity in
pumping and filling, salad dressings,
emulsifier, gravy, improving freeze
thaw mouthfeel
Carrageenan
Seaweed
Gelling milk based desserts
Celluloses
Plants
Stabilisers in ice cream, emulsifies
cream substitutes, salad dressing,
prevents syneresis in meringues
 Some
products need their acidity increasing
or decreasing to improve their palatability.
 Acetic acid (vinegar), tartaric acid (used in
baking) and calcium citrate (soft drinks) are
examples.
 These
additives prevent foods from splitting
into watery and fatty layers.
 An emulsifier enables an oil to be dispersed
in a liquid without it separating.

Eg mayonnaise, soup, sauces
A
stabiliser is used to bind large quantities of
water into a stable form.

Eg ice cream
 To
be successful foods must have an
appealing taste smell, mouthfeel and
appearance.
 In Britain until recently the trend has been to
consume coloured
foods.
 This has recently
reversed and many
consumers seek out naturally coloured foods.
 There
are around 3000 food flavouring
substances.
 The majority do not have an “E” prefix
because they are natural substances.
 Flavourings are odours detected by the nose.
 Our mouth is only capable of tasting salt,
sour, bitter and sweet flavours.
 On
food labels, flavours must be correctly
described



Raspberry-flavour yoghurt has no raspberry in it
at all
Raspberry flavoured yoghurt must have some real
raspberry in it
Raspberry yoghurt must be made with real
raspberries
 Some
additives are used to improve the flavour of
other substances or to modify or mask undesirable
flavours.
 MSG is the most common flavour enhancer.
 MSG stimulates the taste buds in the mouth.
 Over consumption can cause dizziness, sickness and
nausea.
 Saccharin
has been used for many years as a
sweetener.
 Aspartame is used in diet drinks. It is made from two
amino acids, aspartic acid and phenylalanine.
 Acesulfame is also used.
 Colourings
are sometimes used to improve a products
visual appeal.
 They can be used to restore colours in processed
food.
 Some dyes such as tartrazine (E102) have recently
become unpopular due to some consumers suffering
adverse reactions.
 Some colours such as lycopene (from tomatoes) are
natural.
 Colourings
are sometimes used to improve a products
visual appeal.
 They can be used to restore colours in processed
food.
 Some dyes such as tartrazine (E102) have recently
become unpopular due to some consumers suffering
adverse reactions.
 Some colours such as
lycopene (from tomatoes)
are natural.
 Preservatives
help to extend a products shelf life over
a longer period than normal.
 This can help reduce food waste and the risk of food
poisoning to consumers.
 Fats oils and foods containing them are subject to
oxidation which results in rancidity.
 UV rays, copper and iron accelerate this.
 Antioxidants are added to prevent rancidity.
 Some
antioxidants stop chemical reactions which
cause rancidity, some remove oxygen from the
product.
 Hydrolytic rancidity cannot be prevented in butter as
it is caused by the presence of water.

Examples of antioxidants are ascorbic acid (E300) – used in
fruit juice and propyl gallate (E310) - used in vegetable
oils and chewing gum.
 This
group includes minerals, vitamins and protein
supplements.
 Some nutrients are added by law ie A and D is added
to margarine.
 Breakfast cereals have many
nutrients added such as vitamin
C, B6, D, B1, B2, folic acid, iron and
niacin.
ADDITIVES
NUMBERS
Colours
100-180
Preservatives
200-190
Antioxidants
300-321
Acids, buffers, antifoaming
agents
Some 300’s, from 170 to
900
Emulsifiers and stabilisers
322-494
Sweeteners
420-421
Caffeine: linked to peptic ulcers, insomnia,
nervousness and birth defects.
 Monosodium Glutamate (MSG): linked to
headaches, tightness in the chest, and a
burning sensation in the forearms and back of
the head.
 Nitrite and Nitrate: Meat preservatives that
can form powerful cancer causing chemicals
when heated.
 Saccharin: linked to cancer in laboratory
animals.
