Functional properties of food

1. Functional properties of foodFunctional properties of food
Food designers need
to understand the
properties of foods
when they are
designing new dishes,
to make sure they
match the product
profile.

2. SolutionsSolutions
Examples of a solution are
 Fruit juices
 Sugar and water syrups
 Salt and water brine
A solution is formed when
 A liquid is dissolved in
another liquid, for example
fruit squash in water
 A solid is dissolved in a
liquid like sugar in a cup of
tea.
Solutions will not separate
when left to stand.

3. SuspensionsSuspensions
 A suspension forms when
solid particles are added to
liquid but do not dissolve
 Starch particles such as
flour do not dissolve in a
liquid but they form a
suspension.
 If the suspension is not
agitated the solid particles
fall to the bottom . One
example is when a sauce
pan is not stirred when
heated and lumps form at
the bottom of the pan.

4. GelsGels
 A gel is a solid jelly-like
substance. Gels are mostly
liquid but behave like a
solid due to the gelling
agent holding the liquid in
place.
 Gels form when starch is
heated in a liquid and
cooled(gelatinisation).
Examples include
 White sauce
 Lemon meringue pie filling
 Jam
 Flan glaze

5. Smart starchesSmart starches
 Manufacturers use a large
number of starches which have
been altered to change their
working properties. These are
known a modified starches or
smart starches.
 Some modified starches are pre-
gelatinised. This allows them to
thicken instantly such as cup a
soups or pot noodles
 Some modified starches allow
sauces to be reheated with no
synerisis
 Some modified starches are not
affected by acidity so can be used
to thicken salad dressings.

6. EmulsionsEmulsions
 Liquids that will not mix
together are immiscible
such as oils and water.
 When shaken together they
form an unstable emulsion
which separates if left
standing.
 A mixture only remains
stable if an emulsifier is
used. Lecithin in egg yolk is
an emulsifier.
 Egg yolk is used in the
preparation of mayonnaise
where it holds oil and vinegar
together.
 It helps the fat in the cake
mix with the egg white.

7. FoamsFoams
Foams are gas mixed
into a liquid giving a
light texture like in ice
cream.
Meringues are a foam
made by whisking air
(gas) into egg white
(liquid).
When you bake then
the air expands and
the egg white
coagulates to give a
solid structure.

8. ElasticityElasticity
Wheat contains two
proteins glutenin and
gliadin. When water
is added to wheat
flour they form
gluten.
Gluten is very stretchy
or elastic it allows
food made from wheat
flour such as bread
and cakes to rise.

9. PlasticityPlasticity
 Plasticity describes how
fats change shape under
pressure such as rubbing in
or spreading
 You can easily rub in
 Soft margarine
 Butter
 Lard
 Oil cannot be easily
rubbed in
 Plasticity allows fat to coat
each flour particle in
rubbed in products like
short crust pastry or
shortbread.

10. ShorteningShortening
 Fats make cakes and biscuits
crumbly and melt in the
mouth by forming a coating
around the starch and protein
molecules in the flour.
 This stops the liquid coming
into contact with the flour
and helps stop gluten forming.
 Any gluten that does form is
in short lengths not the long
elastic strands found in bread.
 These short gluten strands
give us the term shortening.