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Cooking with Vegetable Oils L.O: To understand why people cook foods in oil and how they can be turned into vegetable spreads.

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Presentation on theme: "Cooking with Vegetable Oils L.O: To understand why people cook foods in oil and how they can be turned into vegetable spreads."— Presentation transcript:

1 Cooking with Vegetable Oils L.O: To understand why people cook foods in oil and how they can be turned into vegetable spreads

2 Chip pan fire – the oil is really hot!

3 Anagrams nkalea eatatsdur iilsttioladn onoremm uoisantrnatu plmeroy uredaanstut droanbroych nkgricca Alkane Saturated Distillation Monomer Unsaturation Polymer Unsaturated Hydrocarbon Cracking

4 What should you cook potatoes in? oil or water? The difference is that oil is at a much higher temperature - the molecules in oils are much bigger so the forces between molecules are much larger, making it boil at a higher temperature. During cooking permanent chemical reactions occur in the food this is why the taste changes Why does frying cook potatoes and other foods quicker than boiling them?

5 What is the impact of oils on your diet?

6 Clogged Arteries

7 Supersize vs superskinny http://www.youtube.com/watch?v=y4jHNrg9 KYU&feature=relmfu

8 Which would be the best fat to use in food? OilMelting point (˚C) Volume of bromine water reacted (cm 3 ) 123 Olive-522.622.422.2 Palm3414.715.315 Sunflower-1634.634.534.7 rapeseed-1127.127.526.7 a.Calculate the mean volume of bromine water reacted for each oil b.Explain which oil is the most unsaturated c.Explain the relationship between amount of unsaturation and its melting point d.Coconut oil reacted with 3.2cm 3 of bromine water in a similar experiment. Predict giving reasons, the state of this oil at room temperature

9 Making margarine Unsaturated vegetable oils are usually liquid at room temperature: Can you explain why? the carbon-carbon double bonds stop the chains fitting together very well. Removing some of the double bonds and adding hydrogen increases the melting point. This is called hydrogenation. Can you explain why butter is more solid at room temperature than margarine?

10 Turning unsaturates into saturates The unsaturated fat is hardened by “hydrogenation”. Hydrogenated oils have a higher melting point and so are solid at room temperature. 60 0 C, Nickel catalyst

11 Trans-fats What are trans fats? How are trans-fats made? What are the health problems associated with trans-fats? Do modern margarines contain trans- fats?

12 What is this?


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