Transcript basic cooking principles 1

basic cooking principles
Judgment, Knowledge, Experience
effects of heat on foods
Foods are composed of proteins, fats, carbs,
water, and vitamins and minerals.
They also consist of flavors and pigments
(coloring agents).
Cooking affects all these components.
Cooking involves the chemical and physical
reactions that affect the food.
carbohydrates
Starches and sugars are
carbohydrates.
Found in fruits, vegetables,
grains, beans, nuts.
heat affects on carbs
1) CARAMELIZATION
: the browning of the
sugars. Examples:
browning of sauteed
vegetables and the
browning of bread
crusts.
heat affects on carbs
2) Gelatinization: The
absorption of water by
starches causes the
starch to swell. The
chemical reaction used
for thickening sauces
and production of
bread and pastries.
Acids inhibit
gelatinization.
fruit and vegetable fibre
fruit & vegetable fiber
Fiber - provides structure and firmness to plants.
Fiber - cannot be digested.
Cooking fruits and vegetables breaks down the
fiber.
Sugar makes fiber stronger. Sugar assists fruits
in keeping their shape when cooked.
Alkalis, such as baking soda, makes fiber softer.
They become mushy and lose flavor.
proteins
Protein is the major component of meats, poultry,
fish, eggs, and milk.
proteins - coagulation
Proteins become DENATURED when the amino
acids are heated and begin to break down.
proteins - coagulation
The strands then become attracted to one
another and begin to BOND.
This bonding is called COAGULATION
coagulation
The solid network of these bonds becomes firm .
As the protein heats, it shrinks, becomes firmer
and loses moisture.
Coagulation, (cooking), is usually completed at
160 - 185 degrees F.
maillard reaction
Meat protein contains a small
amount of carbohydrates.
When heated above 310° F
the amino acids react with the
carbohydrate molecules in a
chemical reaction.
This occurs when meats
brown and is called the
MAILLARD REACTION.
This is done by searing the
meat on a very hot dry
connective tissue in meat
connective tissue
Proteins present in meats.
Meats with a lot of connective tissue are tough.
Some connective tissue dissolves during
cooking.
ACIDS - speed coagulation AND help dissolve
connective tissue.
fats
1.Fats are present in small quantities in most
foods, they are present in larger quantities in:
meats, poultry, fish eggs, and milk products.
2.Fats are important in cooking methods such as;
frying.
3.Can be either solid or liquid at room temperature.
Liquid fats are oils. Solid fats melt to become oils
and change from solid to liquid. The melting
point of fats varies.
smoke point
Fats begin to break down when heated.
When hot enough, they deteriorate and begin to
smoke.
This is called the SMOKE POINT. It varies
among fats.
A STABLE FAT has a high smoke point. It can be
heated to a higher temperature, which is
important when deep frying.
oil smoke points
oils &flavorings
Many flavors
dissolve in fat & oil.
Fats are important
carriers of flavor.
Flavors and vitamins
can be lost when
fats melt.
minerals, vitamins, pigments,
flavors
1. Vitamins and minerals are important
for nutrition.
2. Pigments and flavor are important for
appearance.
3. Some are soluble in water and others
are soluble in oil. It is important not to
destroy these when cooking.
4. It is important to use cooking methods
that preserve a food’s nutrients, taste,
& appearance.
WATER
I. Nearly all foods contain water.
II.Dried foods contain as little as a fraction of
1% water.
III. Fresh meat, fish, vegetables, and fruits
consist mostly of water.
IV.Three states of water: SOLID, LIQUID, GAS
V. LIQUID freezes at 0° C.
VI. BOILS at 100° C and turns to steam.
water
VII. Water can also turn to gas at very low
temperatures: EVAPORATION.
VIII. Evaporation is responsible for the drying
of foods.
IX. This drying of foods allows them to be
browned.
X.When water carries compounds such as
sugar or salt, the boiling and freezing points
vary.
heat transfer
In order for food to be cooked; HEAT MUST BE
TRANSFERED BY A HEAT SOURCE TO AND THROUGH
THE FOOD.
The ways heat are transfered and the speed they are
transfered at affect the cooking outcome.
conduction, convection, radiation or a
combination.
CONDUCTION
conduction
1. Heat moves directly from one item to something
touching it.
2.Heat moves from one part of something to other
parts of the same item - through the food, from the
exterior to the interior.
3.Heat moves rapidly through copper and aluminum,
slower through stainless steel, slower through glass
& porcelain.
convection
Heat is spread by
movement of air, liquid
or steam.
Natural - Hot liquids &
gases rise while cooler
ones sink. Natural
circulation distributes
heat.
Mechanical convection
Mechanical Heat
Transfer - Fans speed
the transfer of heat - the
food cooks faster.
Stirring is a form of
mechanical convection.
Rate of Convection
differs with thickness of
liquid.
Once the heat is carried
to the food; it is then
distributed by
radiation
Energy is transfered by waves from a source to the
food.
Waves are changed to heat energy when they hit the
food.
Radiation in the Kitchen - INFRARED &
MICROWAVE.
microwave
The water molecules are agitated by the radiation
energy, which creates heat and thus cooks the
food.
Waterless materials will not heat.
Microwaves can only penetrate 2 inches into
foods.
Larger foods are heated by conduction.
infrared
Broiling - most common
An electric or ceramic
element heated by gas or
electric, becomes so hot that it
gives off infrared radiation.
High intensity infrared ovens
designed to heat food rapidly.