Gelatinisation- White Sauce and Pasta
Gelatinisation is the thickening of starch in the presence of heat and moisture. The
ingredients that cause this are butter, milk and flour.
A basic white sauce is an excellent base for a variety of pasta dishes. It is also a lower fat alternative to cream base sauces, yet has a similar flavour. Use the following recipe to create your own white sauce and pasta dish.
Recipe between 2
Equipment
2 medium or large saucepans
Frying pan
Colander
Cooks knife
silicon or timber spatula
Cutting board
Scrap bowl
Ingredients
1 Tablespoon of margarine or butter
1 Tablespoon of plain flour
1 Cup of milk
1/2 cup of cheese
100 grams of pasta
Additional vegetables of your choice.
Method
1) Melt margarine in a saucepan
2) stir in flour and cook over heat for about 1 minute. This mixture is called a roux
3) Add milk gradually and stir continuously over heat until mixture boils and thickens. (changes in viscosity)
4) Cook your pasta in boiling water for 12-15 minutes in boiling water.
5) Using your colander strain the pasta
6) cook any additional vegetables.
7) Finally combine the sauce, pasta and vegetables and serve
* If you are unsure how to cook pasta follow the following steps.
1) Place a saucepan of water (3/4 full) on to boil
2) Once boiling place the pasta into the water
3) Cook for 12-15 minutes until eldante (firm to touch)
4) once cooked drain in a colander.
Some questions you may have.
Q1. Why does the roux mixture need to be cooked for approximately 1 minute?
By cooking the roux mixture for approximately 1 minute it allows the fat (butter) to cover the flour and starchy flavour. It is also for the tenderness.
Q2. What is meant by the term 'gelatinisation' and which the ingredients in this recipe take part in this reaction?
Gelatinisation is the thickening of starch in the presence of moisture and heat. The ingredients that take place in this reaction are butter, milk and flour.
Q3. What are the two chemical changes that take place?
The colloidal system changes from a temporary suspension to a permanent suspension. This helps give it flavour so it doesn't just taste like flour.
Q4. What are two over chemical changes that take place in gelatinisation?
There is a change in viscosity as it gets thicker and the colour and flavour also change.
Q5. What are the three most significant factors that affect the physical and chemical reactions in gelatinisation? and Why?
Firstly temperature (heat), you must reach 100 degrees Celcius for gelatinisation to occur.
Secondly stirring (agitation), to prevent the flour from settling and creating lumps.
Thirdly Ratios between ingredients (e.g. flour-milk), ratios are very important as it determines the thickness of the sauce.
Q6. What is Viscosity?
Viscosity is the level of resistance to flow. Similar to thickness.
Some examples are:
Vegemite- High
Honey- Medium
Milk- Low
Just as a note, a commonly asked question is what happens if the cheese boils. Don't allow it to or it will harden.
Evaluation:
Gelatinisation is absolutely vital once again to this dish. Without it you would have an extremely runny lumpy sauce. You would also only be able to taste flour and milk which isn't nice. Gelatinisation adds flavour and viscosity. As stated earlier the viscosity is the main change, in this case the viscosity rises quite significantly.
Gelatinisation is the thickening of starch in the presence of heat and moisture. The
ingredients that cause this are butter, milk and flour.
A basic white sauce is an excellent base for a variety of pasta dishes. It is also a lower fat alternative to cream base sauces, yet has a similar flavour. Use the following recipe to create your own white sauce and pasta dish.
Recipe between 2
Equipment
2 medium or large saucepans
Frying pan
Colander
Cooks knife
silicon or timber spatula
Cutting board
Scrap bowl
Ingredients
1 Tablespoon of margarine or butter
1 Tablespoon of plain flour
1 Cup of milk
1/2 cup of cheese
100 grams of pasta
Additional vegetables of your choice.
Method
1) Melt margarine in a saucepan
2) stir in flour and cook over heat for about 1 minute. This mixture is called a roux
3) Add milk gradually and stir continuously over heat until mixture boils and thickens. (changes in viscosity)
4) Cook your pasta in boiling water for 12-15 minutes in boiling water.
5) Using your colander strain the pasta
6) cook any additional vegetables.
7) Finally combine the sauce, pasta and vegetables and serve
* If you are unsure how to cook pasta follow the following steps.
1) Place a saucepan of water (3/4 full) on to boil
2) Once boiling place the pasta into the water
3) Cook for 12-15 minutes until eldante (firm to touch)
4) once cooked drain in a colander.
Some questions you may have.
Q1. Why does the roux mixture need to be cooked for approximately 1 minute?
By cooking the roux mixture for approximately 1 minute it allows the fat (butter) to cover the flour and starchy flavour. It is also for the tenderness.
Q2. What is meant by the term 'gelatinisation' and which the ingredients in this recipe take part in this reaction?
Gelatinisation is the thickening of starch in the presence of moisture and heat. The ingredients that take place in this reaction are butter, milk and flour.
Q3. What are the two chemical changes that take place?
The colloidal system changes from a temporary suspension to a permanent suspension. This helps give it flavour so it doesn't just taste like flour.
Q4. What are two over chemical changes that take place in gelatinisation?
There is a change in viscosity as it gets thicker and the colour and flavour also change.
Q5. What are the three most significant factors that affect the physical and chemical reactions in gelatinisation? and Why?
Firstly temperature (heat), you must reach 100 degrees Celcius for gelatinisation to occur.
Secondly stirring (agitation), to prevent the flour from settling and creating lumps.
Thirdly Ratios between ingredients (e.g. flour-milk), ratios are very important as it determines the thickness of the sauce.
Q6. What is Viscosity?
Viscosity is the level of resistance to flow. Similar to thickness.
Some examples are:
Vegemite- High
Honey- Medium
Milk- Low
Just as a note, a commonly asked question is what happens if the cheese boils. Don't allow it to or it will harden.
Evaluation:
Gelatinisation is absolutely vital once again to this dish. Without it you would have an extremely runny lumpy sauce. You would also only be able to taste flour and milk which isn't nice. Gelatinisation adds flavour and viscosity. As stated earlier the viscosity is the main change, in this case the viscosity rises quite significantly.