What is Gelatinisation?
Gelatinisation can simply be described as a thickening of starch only in the presence of moisture and heat.
The starch molecules in the solvent (liquid) is heated, which causes them to burst at a specific temperature (84 Degrees Celsius), and absorb the solvent, therefore the solute (starch molecules) and solvent resulting in a thick, viscous solution.
Here are a number of foods we eat which depends on gelatinistion:
The starch molecules in the solvent (liquid) is heated, which causes them to burst at a specific temperature (84 Degrees Celsius), and absorb the solvent, therefore the solute (starch molecules) and solvent resulting in a thick, viscous solution.
Here are a number of foods we eat which depends on gelatinistion:
- White sauce in pasta
- Custard
- Curry
- Risotto
- Cheese souffle
Why is gelatinisation important?
Gelatinisation is very important for creating a series of vital chemical changes. Without gelatinisation to create specific chemical reactions, many carbohydrates we consume would be unpalatable and harder to digest.
Physical changes?
Physical changes that takes place during the gelatinisation process are:
Viscosity- Resistance to movement.
- The solution is in a temporary (runny) state at first, however, as heat is constantly applied, the solution gradually changes to a permanent (thick) state.
- Changes of texture and color will occur. The mixture would normally start with a fluid-like texture and after application of heat, the texture should be smooth and dense. The color varies on the type of starch and ingredients you are using, however, the color often results in a light yellow, light beige or creme.
Viscosity- Resistance to movement.
Chemical changes?
- Viscosity of the solution changes depending on its state (temporary or permanent).A temporary solution's viscosity would be low, on the other hand, a permanent solution would have high viscosity. Low viscosity would be like milk as it is runny and moves very easily. Whereas, high viscosity would be like white sauce, as it is thick and its movements are gradual.
- The chemical changes in gelatinisation occurs when the starch molecules burst.
The inter-molecular bonds are broken down from the heat that is applied to the solution, which then allows the starch to mix with the water molecules and forms gel after cooling.
Gelatinised Food
- White sauce
- Beef stir fry sauce
White sauce for pasta
Serves for one person
Ingredients:
Additional ingredients:
Equipments:
Method:
The expected sauce should be nice and smooth and dense with a yellow tinge to it.
Serves for one person
Ingredients:
- 1 Tsp margarine or butter
- 1 Tsp plain flour
- 1 cup milk
Additional ingredients:
- 1/2 cup cheese (for serving)
- 100g pasta
Equipments:
- Medium saucepan (sauce)
- wooden spoon
- Measuring cup
Method:
- Melt the margarine in the medium saucepan over low heat. (always use low heat as the sauce can easily burn.)
- With a wooden spoon, stir in the flour and cook for about 1 minute. this mixture is called a roux.
- Add milk in the saucepan in three separate portions and stir continuously over the heat until mixture boils and thickens.
The expected sauce should be nice and smooth and dense with a yellow tinge to it.
When stirring the sauce...
When you are stirring the sauce, make sure that the flour hasn't sunk to the bottom of the saucepan and stir it up to avoid burning of your sauce.
No one would want burnt sauce on their plate!
No one would want burnt sauce on their plate!
Beef stir fry sauce
Serves for two people
Ingredients:
Method:
Remember to stir the sauce continuously to prevent your sauce from burning.
The sauce should be smooth and translucent with no lumps of arrowroot flour and a watery texture..
Serves for two people
Ingredients:
- 2 tsp Arrowroot flour
- 1/2 cup of water
Method:
- In a small saucepan on low heat, gradually add the arrowroot flour to the water while slowly mixing until the sauce has a smooth, consistent texture.
- gradually add your sauce to the stir fry mixture while stirring.
Remember to stir the sauce continuously to prevent your sauce from burning.
The sauce should be smooth and translucent with no lumps of arrowroot flour and a watery texture..
Picture of arrowroot sauce after it has cooled.