Download Lesson 3 Heat in Cooking

Heat in Food Preparation
Heat – a form of energy caused by the
vibratory or kinetic movement of molecules
Sources of heat in cooking:
wood
gas
charcoal
electricity
Media for heat penetration:
1. Water – simmering, stewing, boiling,
poaching
2. Air – baking and oven cooking
3. Steam – pressure cooking and
steaming
4. Fat – sautéing and deep fat frying
5. Combination – braising and potroasting
Kinds of Heat Transfer
1. Conduction – the direct transfer of
heat via metals or any heat-conducting
materials containing food (copper –
highest rate of conductivity)
Kinds of Heat Transfer
2. Convection – the transfer of thermal
energy from electricity, gas or solid fuel
to the vapor molecules of the air which in
turn heat the food on the utensils it
comes in contact with (oven, turbo
broiler)
Kinds of Heat Transfer
3. Radiation – the transfer of heat from
a red hot coil of the griller, toaster or
stove to the food in a manner similar to
how light passes from a bulb to the
object it illuminates (infrared)
Kinds of Heat Transfer
4. Microwave cooking – uses radiation
emitted by a magnetron tube to the heat
substances containing water
Effects of Heat Transfer
1. Meat Shrinkage – usually happens when meat
is cook slowly at temperatures ranging from 300
F to 350 F.
2. Deterioration of Fats and Oils
3. Changes in protein
4. Excessive heating of meat losses its nutritive
value and it becomes tough.
5. Nutrient Losses
Methods of Heat Transfer
Dry – heat method – the surrounding
air transmits heat to the food and then
the moisture is allowed to evaporate to a
certain degree
Methods of Heat Transfer
Moist-heat method – the liquids are
used to transfer heat to the food
Methods of Heat Transfer
Combination Cooking method:
First step: brown the main ingredient
using dry heat method
Second step: complete the cooking by
simmering the food in liquid
Ex: Braising and Stewing
Heat in Cookery
Heat is applied to food primarily for cooking but can also be
used for food preservation as in drying, sterilization and
pasteurization
Cooking:
- to produce a more palatable food
- to render the food safer from parasites &
microorganisms
- to make it more digestible
- alters color & texture & develops flavor
- temporary preservation (cooked food can stand
longer than raw food)
- destruction of microorganisms & destruction of
enzymes
Heat in Cookery
Undesirables changes: destruction of nutrients &
reduction of sensory attributes as color, flavor, and
texture