Fats & Oils

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Changing Properties - Fats and Oils

We can use fats and oils for different effects when we're cooking.

Aeration

Aeration involves getting air into something.
We trap air in mixtures when we beat fats with sugar (known as creaming).
The added air lightens the mixture and gives it a fluffy texture.
Aeration causes cakes to turn out spongy and light when they're cooked.
We can use different methods to aerate foods, including beating or whisking.

Shortening

Flour particles gain a waterproof layer when they're covered in fat. We can cover particles in fat by rubbing fat into flour.
We might choose to do this if we want to form baked goods with firm textures (i.e. cakes, biscuits or shortbread). This is because the coating stops long gluten molecules from forming when we add water to flour. The dough doesn't develop an elastic (stretchy) texture.
We use shortening to form pies and tarts because we want the base to be solid and not rise.
Shortening fats don't contain any water - they are made of fat only. This prevents gluten from forming.

Plasticity

If something has plasticity, it can be spread and moulded.
We can spread and mould fats because they are made up of different triglycerides that each have different melting points. This means fats don't melt at a set temperature but soften gradually across different temperatures.
Fats with more plasticity are easier to spread.
Fats with more unsaturated fatty acids have more plasticity than those with less and are easier to spread.
Plasticity is useful in everyday cooking. For example:
- Spreading peanut butter, aioli or butter on toast.
- Making cream cheese and smoked salmon sandwiches.
- Icing cupcakes with buttercream.

'Easy to spread'

You'll see some vegetable fat spreads labelled as 'easy to spread'.
These spreads are made up of triglycerides that melt at low temperatures (e.g. room temperature) so they're spreadable once they're out of the fridge.

Changing Properties - Fats and Oils

We can use fats and oils for different effects when we're cooking.

Emulisification

When we shake watery and oily liquids together, we create emulsions. Droplets from one of the liquids disperse throughout the other liquid.
We either create oil-in-water emulsions, like milk and vinaigrette, or water-in-oil emulsions, like butter and margarine.
We need to keep stirring or shaking the oily water so that the emulsions don't separate - they do this because oil and water don't naturally mix together. We can also use an emulsifier.

Emulsifier

Emulsifiers are dual-ended molecules. They have a:
- Hydrophilic end (water-loving) - bonds with water molecules.
- Hydrophobic end (water-hating) - bonds with oil molecules.
The emulsifier keeps the water and oil together in what's called a stable emulsion. This means they don't separate.

Lecithin

Lecithin is a natural emulsifier found in egg yolks and soya.
- It's commonly used in foods, like mayonnaise, which is made up of oil, vinegar and egg yolk in a stable emulsion.

Sauces and salad dressings

Mayonnaise and hollandaise sauce are examples of emulsion sauces.
Vinaigrette is an example of an emulsion salad dressing.
You must add liquid and emulsifier before you add oil or fat when you're creating an oil-in-water emulsion. You must add the fat or oil very slowly and stir continuously as you add.

Recipe for hollandaise sauce

Place butter in a pan and melt.
Place lemon juice and egg yolks into a mixing bowl and stir.
Place the mixing bowl over simmering water to heat the mixture gently.
Slowly pour the melted butter into the mixing bowl, whisking continuously.
Whisk until the mixture is smoothly mixed.

1Food Preparation Skills

1.1Food Preparation Skills

1.1.1General Practical Skills

1.1.2Knife Skills

1.1.3Preparing Fruit, Vegetables & Using Equipment

1.1.4Cooking Methods: Prepare, Shape & Combine

1.1.5Sauce Making, Tenderising & Marinating

1.1.6Dough & Pastry

1.1.7Shaping & Finishing Dough

1.1.8Raising Agents & Mixtures

1.1.9End of Topic Test - Food Preparation Skills 1

2Food, Nutrition & Health

2.1Macronutrients

2.1.1Proteins

2.1.2Proteins 2

2.1.3Fats

2.1.4Carbohydrates

2.1.5Carbohydrates 2

2.2Micronutrients

2.2.1Fat-Soluble Vitamins

2.2.2Water-Soluble Vitamins

2.2.3Minerals & Water

2.2.4Minerals & Water 2

2.2.5End of Topic Test - Macro & Micronutrients

2.3Nutritional Needs & Health

2.3.1Informed Choices for a Balanced Diet

2.3.2Informed Choices for a Balanced Diet 2

2.3.3Energy Needs

2.3.4Nutritional Analysis

2.3.5Diet Modifications

2.3.6Diet-Related Problems

2.3.7Diet-Related Problems 2

2.3.8End of Topic Test - Nutritional Needs & Health

3Food Science

3.1Cooking of Food & Heat Transfer

3.1.1Reasons for Cooking & Heat Transfer

3.1.2Water-Based Cooking Methods

3.1.3Fat-Based Cooking Methods

3.1.4Dry Cooking Methods

3.1.5Dry Cooking Methods 2

3.2Functional & Chemical Properties of Food

3.2.1Proteins & Carbohydrates

3.2.2Fats & Oils

3.2.3Raising Agents

3.2.4End of Topic Test - Food Science

4Food Safety

4.1Food Spoilage & Contamination

4.1.1Microorganisms & Signs of Food Spoilage

4.1.2Enzymes & Signs of Food Spoilage

4.1.3Food Poisoning

4.1.4Bacterial Contamination

4.1.5Microorganisms in Food Production

4.2Principles of Food Safety

4.2.1Temperature Control

4.2.2Ambient Foods & Food Labels

4.2.3Preparing, Cooking & Serving Food

4.2.4End of Topic Test - Food Safety

5Food Choice

5.1Factors Affecting Food Choice

5.1.1Factors Which Influence Food Choice

5.1.2Food Choices

5.1.3Religious Food Choices

5.1.4Food Labels

5.1.5Mandatory Food Labels

5.1.6Optional Food Labels

5.1.7Marketing Influences

5.1.8End of Topic Test - Food Choice

5.2British & International Cuisines

5.2.1British Cuisine

5.2.2Japanese Cuisine

5.2.3Japanese Ingredients & Dishes

5.2.4Spanish Cuisine

5.2.5Spanish Ingredients & Dishes

5.3Sensory Evaluation

5.3.1Taste Receptors & Olfactory Systems

5.3.2Sensory Testing Methods

5.3.3Sensory Testing Methods 2

5.3.4End of Topic Test - Cuisines & Senses

6Food Provenance

6.1Environmental Impact & Sustainability of Food

6.1.1Food Sources - Intensive & Organic Farming

6.1.2Food Sources - Genetically Modified Crops

6.1.3Food Sources - Reared Food

6.1.4Food Sources - Caught Food

6.1.5Food & The Environment

6.1.6Food & The Environment 2

6.1.7Sustainability of Food

6.1.8Sustainability of Food 2

6.1.9End of Topic Test - Environmental Impacts

6.2Food Processing & Production

6.2.1Primary Food Processing

6.2.2Primary Food Processing 2

6.2.3Secondary Food Processing

6.2.4Fortification

6.2.5Additives

6.2.6End of Topic Test - Food Processing & Production

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