Functional Properties Flashcards
functional properties
Gelatinisation
Caramelisation
Oxidation
Denaturation
Coagulation
Emulsification
Dextrinization
Rancidity
dextrinisiation
Dry heat causes the break down of starch causing it to break down
Starch changes to dextrins which hare brown and sweet in flavour
Can increase the sweetness of the product
Starch is a carb
Eg
Toast
Roasted potatoes
caramelisation
When the sugar in food is browned which causes a change in flavour and appearance
Sweetens the food product
Requires greater exposure to intense heat and does not require oxygen
Occurs in dry heating methods
Eg
Toffee
Caramel
Fruit cakes
Baking of sweet potato
crystallisation
The heating of a large amount of sugar in water to form a syrup and the cooling
Sugar is dissolved in a liquid and heated, the liquid then evaporates concentration (supersaturating) the sugar solution
As the liquid cools sugar reforms into crystals
If the solution is not stirred the crystals will be very smal and be a smooth texture
Toffee
If stirred larger crystals from which change the texture
Fudge
emulsification
The process used to prevent dissimilar liquids from separating
It is a stable combination of oil and water
Water and oil require an emulsifying agent like egg yolks to not separate
When completed its called an emulsion
Eg
Mayonnaise
Salad dressing
gelatinisation
Occurs when starch cells absorbs moisture and are then heated. They then burst and disperse and thicken the liquid
Requires a separating agent to keep the starch grains apart which can be solid or liquid
Sugar
Powdered milk
Water
Milk
Stock
Common thickening agents are cornflour and wheat flour
Changes the texture of the food which occurs around 90 degrees
Eg
Sauces
Gravies
Cakes
oxidation
A chemical change in foods when it is exposed to oxygen
When any substance looses an electron oxidation has occurred
Acid will prevent the browning process from occurring
Cut open apple
Aged meat
denaturation
The change in structure of protein in food
It is irreversible
The tangled arrangement of amino acids are unravelled
Can be altered by heat or mechanical action
If heat is applied for longer than the process of coagulation occurs
Usually makes food more palatable
Adding acids to meat helps to tenderise the meat by breaking down collagen and connective tissue
Eg
Whisking eggs
Cooking meat
Adding acid like lime juice to fish
coagulation
Is the formation of a clot in proteins as a result of denaturation
Change in protein from a liquid to a solid
Coagulation can only occur is protein is present
Occurs at the same time as denaturation
Eg
Boiling
Production of cheese
Cooking of meat
leavening/aeration
The process of incorporating air into a substance (air for aeration CO2 for leavening)
Aerating agents are also called leavening agents as it assist in the rising of flour mixtures
There are 3 types
Physical
Adding air by sifting
Rolling
Beating
Chemical
Additives that produce CO2 gas
Baking soda
Cream of tartar
Biological
Yeast is a living fungi that multiply with the right moisture and temperature. As it grows it produces CO2
rancidity
The spoilage of fats and oils due to a process of oxidation or hydrolysis
Flavour and aroma are unpleasant and the colour is of the fats and the oils darken
The presence of heat, light, and moisture accelerates the oxidation process
