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07/12/2025
Food & Nutrition
Cooking Fats - the Science
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Properties of Fats and Oils
Fats and oils are absolute game-changers in the kitchen, but they don't just add flavour. They actually transform the texture and structure of everything you cook.
There are four main ways that fats and oils change during cooking: aeration, shortening, plasticity, and emulsification. Each one creates completely different effects in your food.
Quick Tip: Mastering these properties is the secret to understanding why recipes work the way they do!
Key Changes Overview
When you're working with fats and oils, four major transformations can happen. Aeration traps air to make things light and fluffy. Shortening creates crumbly textures by blocking gluten.
Plasticity makes fats spreadable and workable at room temperature. Finally, emulsification helps oil and water mix together properly.
These aren't just fancy cooking terms - they're the science behind every successful cake, pastry, and sauce you'll ever make.
Remember: Each property serves a specific purpose, so understanding when to use each one is crucial for cooking success.
Aeration
Think about beating butter and sugar together - notice how it goes from yellow and dense to pale and fluffy? That's aeration in action, and it's basically trapping tiny air bubbles throughout the mixture.
This process is what makes your sponge cakes light and airy rather than dense and heavy. The trapped air expands when heated, creating that perfect spongy texture you're after.
Creaming butter and sugar is the most common example you'll use. The longer you beat it, the more air gets trapped, and the lighter your final cake will be.
Pro Tip: Properly aerated butter and sugar should look noticeably paler and feel much lighter than when you started!
Shortening
Shortening is all about creating that perfect crumbly pastry texture - think shortbread biscuits or pie crusts. The fat literally coats each flour particle, acting like a protective barrier.
This coating stops the flour from properly absorbing water, which prevents gluten from forming those long, stretchy chains. Without gluten development, you get a firm, crumbly texture instead of something chewy.
Products designed for shortening contain 100% fat with no water content. This is why lard or special shortening fats work brilliantly for pastries, pies, and tarts.
Key Point: The more fat coats the flour, the more 'short' (crumbly) your pastry will be - that's where the term comes from!
Plasticity
Plasticity explains why butter spreads perfectly on toast when it's at room temperature but goes rock-hard in the fridge. It's the fat's ability to be shaped, spread, and manipulated easily.
This happens because fats contain different triglycerides that melt at various temperatures. As it warms up, some parts melt while others stay solid, creating that perfect spreadable consistency.
Fats with more unsaturated fatty acids tend to be more plastic - think about how olive oil stays liquid while coconut oil can be solid or liquid depending on temperature.
Kitchen Hack: This is why recipes often tell you to use 'room temperature' butter - it's at peak plasticity for mixing!
Emulsification
Emulsification is the clever trick that stops oil and water from separating - something that normally happens because they naturally repel each other. Instead of having distinct layers, you get tiny droplets mixed throughout.
You see this everywhere: milk, margarine, mayonnaise, and salad dressings. Without emulsification, these products would separate into greasy, watery messes within minutes.
You can create emulsions through vigorous shaking or stirring, but the really stable ones need special ingredients called emulsifiers to hold everything together permanently.
Real-World Example: Ever noticed how shop-bought mayonnaise stays mixed, but homemade versions sometimes separate? That's emulsification at work!
Understanding Emulsifiers
Emulsifiers are like molecular matchmakers - they have split personalities that help oil and water get along. Each molecule has two completely different ends with opposite properties.
One end is hydrophilic (loves water) while the other is hydrophobic (hates water and loves oil instead). This means water sticks to one end whilst oil attaches to the other, creating a stable bridge between them.
Natural emulsifiers like lecithin are found in eggs and soya, which explains why mayonnaise uses egg yolks. For best results, add your liquids gradually and mix thoroughly - rushing leads to separation.
Science Made Simple: Think of emulsifiers as tiny molecular hands holding oil and water together so they can't separate!
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
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In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding Cooking Fats: Their Functions and Science
Ever wonder why cakes are fluffy, pastry is crumbly, and mayonnaise doesn't separate? It's all down to how fats and oils behave when we cook with them. Understanding these four key properties will transform how you approach baking and cooking.
Properties of Fats and Oils
Fats and oils are absolute game-changers in the kitchen, but they don't just add flavour. They actually transform the texture and structure of everything you cook.
There are four main ways that fats and oils change during cooking: aeration, shortening, plasticity, and emulsification. Each one creates completely different effects in your food.
Quick Tip: Mastering these properties is the secret to understanding why recipes work the way they do!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Key Changes Overview
When you're working with fats and oils, four major transformations can happen. Aeration traps air to make things light and fluffy. Shortening creates crumbly textures by blocking gluten.
Plasticity makes fats spreadable and workable at room temperature. Finally, emulsification helps oil and water mix together properly.
These aren't just fancy cooking terms - they're the science behind every successful cake, pastry, and sauce you'll ever make.
Remember: Each property serves a specific purpose, so understanding when to use each one is crucial for cooking success.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Aeration
Think about beating butter and sugar together - notice how it goes from yellow and dense to pale and fluffy? That's aeration in action, and it's basically trapping tiny air bubbles throughout the mixture.
This process is what makes your sponge cakes light and airy rather than dense and heavy. The trapped air expands when heated, creating that perfect spongy texture you're after.
Creaming butter and sugar is the most common example you'll use. The longer you beat it, the more air gets trapped, and the lighter your final cake will be.
Pro Tip: Properly aerated butter and sugar should look noticeably paler and feel much lighter than when you started!
Sign up to see the contentIt's free!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Shortening
Shortening is all about creating that perfect crumbly pastry texture - think shortbread biscuits or pie crusts. The fat literally coats each flour particle, acting like a protective barrier.
This coating stops the flour from properly absorbing water, which prevents gluten from forming those long, stretchy chains. Without gluten development, you get a firm, crumbly texture instead of something chewy.
Products designed for shortening contain 100% fat with no water content. This is why lard or special shortening fats work brilliantly for pastries, pies, and tarts.
Key Point: The more fat coats the flour, the more 'short' (crumbly) your pastry will be - that's where the term comes from!
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Plasticity
Plasticity explains why butter spreads perfectly on toast when it's at room temperature but goes rock-hard in the fridge. It's the fat's ability to be shaped, spread, and manipulated easily.
This happens because fats contain different triglycerides that melt at various temperatures. As it warms up, some parts melt while others stay solid, creating that perfect spreadable consistency.
Fats with more unsaturated fatty acids tend to be more plastic - think about how olive oil stays liquid while coconut oil can be solid or liquid depending on temperature.
Kitchen Hack: This is why recipes often tell you to use 'room temperature' butter - it's at peak plasticity for mixing!
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Emulsification
Emulsification is the clever trick that stops oil and water from separating - something that normally happens because they naturally repel each other. Instead of having distinct layers, you get tiny droplets mixed throughout.
You see this everywhere: milk, margarine, mayonnaise, and salad dressings. Without emulsification, these products would separate into greasy, watery messes within minutes.
You can create emulsions through vigorous shaking or stirring, but the really stable ones need special ingredients called emulsifiers to hold everything together permanently.
Real-World Example: Ever noticed how shop-bought mayonnaise stays mixed, but homemade versions sometimes separate? That's emulsification at work!
Sign up to see the contentIt's free!
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By signing up you accept Terms of Service and Privacy Policy
Understanding Emulsifiers
Emulsifiers are like molecular matchmakers - they have split personalities that help oil and water get along. Each molecule has two completely different ends with opposite properties.
One end is hydrophilic (loves water) while the other is hydrophobic (hates water and loves oil instead). This means water sticks to one end whilst oil attaches to the other, creating a stable bridge between them.
Natural emulsifiers like lecithin are found in eggs and soya, which explains why mayonnaise uses egg yolks. For best results, add your liquids gradually and mix thoroughly - rushing leads to separation.
Science Made Simple: Think of emulsifiers as tiny molecular hands holding oil and water together so they can't separate!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user