Gelatinisation Flashcards
Give three starchy foods.
Potatoes, pasta, rice
Which is the starchy food used for gelatinisation in the bechamel sauce practical?
Flour, contains wheat.
What happens at 60 degrees C during gelatinisation?
The starch granules absorb the water they are being heated in, causing them to swell up.
What effect does the starch granules swelling up have on the sauce?
It thickens because there is less room for them to move around.
Why must you always stir the sauce during gelatinisation?
Because otherwise the starch granules stay at the bottom of the pan, swell up, stick together and the sauce will be lumpy
What happens at 80 degrees C?
The starch granules burst and release starch molecules into the surrounding liquid?
What do the released starch molecules do?
They form a 3D network which traps water molecules and stops them moving.
What happens at boiling point (100 degrees C?)
The sauce completely thickens.
What is the process known as?
Gelatinisation.
What happens when the sauce cools down?
The starch molecules form longer chains and the water molecules stay trapped inside, so the sauce becomes a solid gel.
Where else can gelatinisation take place?
When any starchy foods are cooked, e.g. boiling pasta.
What happens if starchy foods, e.g. pasta, are cooked for too long?
The released starch molecules will cause the pieces of pasta to stick together.
What is a viscous liquid able to do?
Be poured, use to coat something or bind other ingredients together.
How to change an ingredient’s viscosity?
Change the ratio of thickening agent:liquid i.e. more starch = thicker sauce
Give three examples of starches.
Wheat flour, corn flour and arrow root.
