Gelatinisation of starch – NEA 1

Food and Nutrition GCSE has an Investigation NEA which could be

Investigate the ingredients used to thicken sauces and soups

Look at the Book NEA 1 Food Investigations

This is how I do it:
Think what ingredients are used to thicken sauces and soups and which starch is best for recipes.

White sauce, Tomato sauce or soup, Fruit sauce…

Starchy ingredients thicken sauces when they are heated in liquid.

So test some starches:
Rice starch, cornflour, plain flour, arrowroot, potato flour … you choose.

Create a FAIR TEST. Mix the same amount of starch (10g) with the same amount of water (100ml).

Heat each one in the microwave and look every 20 seconds, stir and remove when it is thick.

Taste and test each one.

Use the Star Profile on the Nutrition Program to show your results:

First list the starches, then choose Descriptors – words to describe the results – thick, creamy, clear, glossy, tasty …

Different starches and gelatinisation
Different starches and gelatinisation
This star profile from Nutrition Program shows tasting results
This star profile shows tasting results

Fill in your tasting results:-

This star from Nutrition Program shows the results
This star shows the results for the starches
This star shows the evaluations of gelatinisation
This star from the Nutrition Program shows the evaluations of gelatinisation
These are the final results of the starch test.
These are the final results of the starch test presented using The Nutrition Program.

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Risotto – gelatinisation

Science term – gelatinisation

You need to use risotto rice as it contains a high amount of starch and gives a soft, creamy texture but the grains remain chewy when cooked.

As you cook this risotto you can see the starch in the rice grains changing as the grains swell, absorb the liquid, swell and release the starch into the cooking liquid.

What can I cook?

 

Pea and carrot risotto

Serves 4

Ingredients

100g onion, finely chopped

30g oil

150g risotto rice

7g vegetable stock cube

600g boiling water

100g frozen peas

1 carrot (60g), grated

30g finely grated Parmesan cheese

5g of parsley finely chopped

Method

Heat the oil in a heavy based pan and add the chopped onion. Stir and cook for 5 minutes until onion is soft.

Stir in the rice and coat the grains in oil.

Dissolve the stock cube in boiling water and gradually stir into the rice.

Cook for 15 minutes as the rice absorbs the liquid. Add the peas and grated carrot and stir.

Taste to see if rice grains are soft and serve with chopped parsley and Parmesan cheese.

Equipment

chopping board, sharp knife, large pan, wooden spoon, grater, measuring jug

Nutrition

Energy per portion (270g) 2371 kcal, Protein 7.5g, Sugar 1.2 g, Fat 3.9g, Salt 0.9g

Allergens none

The science bit

As the rice is cooking, the stirring helps the starch grains release starch into the cooking liquid. The grains soften as the starch gelatinises, and the starch in the liquid thickens the sauce giving the risotto its creamy texture.

Portion sizes

Our portion sizes for the Nutrition Program come from supermarket websites – Sainsburys Waitrose Aldi Co-op Morrisons  Tesco.

Look up the food dish you are making on the supermarket website and see how much a portion weighs. Tesco has a Healthy Living range with reduced salt, sugar, fat and calories
The Co-op has ready meals with less than 500 calories
School Food Plan has excellent charts on portion sizes

School Food Plan portion

BUPA has an excellent website with portion sizes for different foods.

Starchy foods

Strachy food portions

Meat, fish and other proteins

Portion sizes

Dairy foods

portion sizes

Changing sodium to salt

We are told to cut down on salt but sodium is listed on food labels so how do we convert?

To reduce risk of high blood pressure need to limit to 6g of salt a day.

High salt >1.5g per 100g

Low salt < 0.3g per 100g

Watch out for baking powder!

Age Salt intake
1-3 years 2g
4-6 years 3g
7-10 years 5g
11 years and over 6g

Sodium to salt

To convert sodium (mg)  to salt (g), multiply the sodium figure in milligrams (mg) by 2.5 and then divide by 1,000.

So: millgrams of sodium X 2.5 = milligrams of salt ÷ 1,000 = grams of salt

500 mg sodium x 2.5 / 1000 = 1.25 grams salt

In reverse

grams of salt x 1000 /2.5 = mg of sodium

1.25 grams salt x 1000 /2.5 = 500 mg sodium or 0.5 g sodium

Eating too much salt increases your risk of developing high blood pressure which is a major risk factor for heart disease.

Too much salt is harmful to health

Too much salt is harmful to health

 News Flash – Food labelling is changing

By December 2014 all food labels will only list salt -sodium will not be listed. This will make it much easier for you to see how much salt each product contains. So we must change the Nutrition Program to fit in with this.

 Choose lower salt options using the following guidelines on food labels:

A food high in salt has more than 1.5g salt per 100g (or 0.6g sodium).