Transcript Modified Starches - Bohunt School VLE

Modified Starches
Starches, such as corn flour, are commonly used to thicken sauces and soups.
However, it is very difficult to control their thickening action whilst processing
foods commercially. For example, they may thicken too much on heating or form
an undesirable gel on cooling.
This is why starches from a range of natural sources, such as potatoes, maize
or rice are adapted or ‘modified’ to give them specific and controllable functions
when used in different food products.
This involves subjecting the native starches to chemical processes, which alter
them chemically to enhance certain properties.
The main methods of modifying starch are:
Acid hydrolysis (thinned)
Oxidation
Cross linking
A large variety of modified starches are manufactured to:
•Give freeze/thaw stability to cheese sauces – ie in frozen lasagne
or cauliflower cheese
•To allow desserts to cold set as a gel
•To make clear glazes for meats and pies
•To help stabilise emulsions
•Act as fat replacers in lower fat products
•To bind ingredients together
Modified starches are particularly useful in:
Frozen foods
Readymade meals
Microwaveable meals
Sauces
Dressings
Soups
Desserts
Snacks
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.
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.
Mozzarella
Or Modified
Starch?
Cup a Soup v Catering Soup
•Dried soups can be bought in several different forms,
including bulk containers for use in catering.
•The powder will be reconstituted with water, boiled, then left
to simmer until served. Another form is the ‘Cup-a Soup’ style
product in individual packets for instant hydration with
boiling water in a cup.
•The types of modified starch used in the formulation of each
of these two soups will be different. The modified starch used
for the catering soup must allow it to thicken gradually and
stay at that level of viscosity despite prolonged simmering,
whereas the ‘Cup a Soup’ starch will need to swell and thicken
immediately as the hot water is added. Therefore, the
modified starch used in each type of product is quite different
in its function and, although often from the same native
source, they have been adapted in different chemical ways.