Cake Making And Raising Agents Flashcards
When cake making what does flour do?
Forms the structure of cake:
As the cake is heated the protein sets the framework
What does dextrinisation mean?
A browning that occurs when starch is converted to sugar
What is the function of fat?
Adds colour and flavour
Holds air bubbles-which makes volume
Produces short crumb
What is the function of sugar?
Sweetens and adds flavour
Holds air in mixture when creamed with fat
Caramelisation give colour
What does aerate mean?
Introduce air
What is the function of raising agents?
Aerates mixture increasing volume
What is the function of eggs?
Traps air when whisked
Holds fat in emulsion and keeps it stable
Adds colour and flavour
What does it mean when a cake has a peaked cracked top?
Oven temperature was too high
Over mixing
What does it mean when a fake has a heavy texture?
Too much liquid
Too little leavening
What does it mean if fruit has sunk in a fruit cake?
Too runny mixture
What does it mean when a cake has sunk in the middle?
Oven door has been opened
Too much raising agent
What does it mean when a cake has a course texture?
Too much raising agent
What does it mean when a cake has a sugary speckled crust?
Too much sugar
What does it mean when a cake is very dry?
Not enough liquid
Over cooked
What are the gas bubbles in raising agents?
A mixture of
Air
Carbon dioxide
Steam
How is carbon dioxide given off?
Yeast in bread
Bicarbonate of soda added to cake or scone mixtures
Baking powder, which has bicarbonate of soda in it and is added to self -raising flour by food manufacturers
Steam, water in a gaseous state
Name three ways gases are introduced into mixtures
Chemical - using baking powder or bicarbonate of soda go produce C02 gas
Mechanical - by whisking, beating, creaming etc.
Biological - using yeast to produce C02 gas
How does raising agents work?
The action of moisture, heat or acidity triggers a reaction with the raising agent to produce the gas bubbles
As a cake mixture, batter or dough cooks, the gas bubbles given off by the raising agent make it rise by expanding and pushing it
Gas bubbles then become set in and provide the soft, sponge like texture
Explain how creaming causes a cake to rise
When fat and sugar are beaten together lots of air bubbles are trapped in the mixture
Each bubble is surrounded by a thin layer of fat
The mixture changes colour during creaming as trapped air creates a foam
Egg is added to the mixture to coagulate and form a wall round the air bubbles so they expand and raise the mixture
The mixture sets as the egg proteins coagulate and starch granules in flour completely expand as as it sets, air escapes from mixture
What is carbon dioxide gas produced by?
Bicarbonate of soda and yeast
If bicarbonate of soda is used on its own in a mixture, what will happen?
They would rise well but the taste of the washing soda produced in the reaction would be very unpleasant
What is the reaction by bicarbonate of soda is used on its own in a mixture?
Bicarbonate of soda + heat —> washing soda + carbon dioxide gas + water
To prevent the washing soda taste of bicarbonate of soda, what must be done?
Bicarbonate of soda is mixed with an acid called cream of tartar to make baking powder
If you put an acid and an alkali, C02 gas will be produced, but the acid and alkali will neutralise each other, so that you do not get washing soda produced
What is the reaction when cream of tartar is added to a mixture
Bicarbonate of soda + cream of tartar + heat —> sodium potassium tartrate + carbon dioxide gas + water
Explain how Yeast acts as a raising agent
C02 gas will make the bread dough expand and rise when it is left in a warm place
When bread is being made and dough is left to rise, Yeast cells multiply (budding)
This means there are more yeast cells to produce C02 so the bread will rise and expand well
When bread is put in the oven, the C02 gas bubbles expand with heat and steam and alcohol are produced as dough heats up
The alcohol evaporates in the heat of the oven when the loaf is baked so there is no alcohol left when the bread comes out of the oven
Yeast cells will die if they come into direct contact with salt or boiling water
What are chemical raising agents?
Bicarbonate of soda is an alkali raising agent that breaks down when it’s heated. Carbon dioxide bubbles form and, when they expand, cause a mixture to rise.
Baking powder contains both bicarbonate of soda and an acidic substance called cream of tartar. Heating baking powder sparks a neutralisation reaction
How do mechanical processes act as raising agents?
We can fold air into doughs and mixtures by:
Literally folding pastry doughs into layers. Air gets trapped between folds.
Using the folding technique for mixtures. This involves using a spatula or spoon to cut through the mixture and pour it over itself to trap air.
Sieving ingredients like flour traps air between individual particles.
Creaming adds air.
Rubbing fat into flour introduces air between individual flour particles
