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Lipids

Lesson 3

This Photo by Unknown Author is licensed under CC BY-SA

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K-Know

W-want

L-learn

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  1. Identify the functions of lipids

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2. Describe the effects of heat on lipids

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3. Analyse the lipid property of emulsification

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Lipids?

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Worksheet: https://app.wizer.me/preview/HWG2WZ

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Functions of lipids?

  • https://whiteboard.fi/

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Functions:

  • Supply heat and a good source of energy.

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  • Protect delicate organs and nerves.

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  • Foods containing lipids supply fat soluble vitamins-A,D, E, K.

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  • Excess lipids stored as adipose tissue, insulates the body and acts as an energy reserve.

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Lipid overconsumption?

  • Obesity
  • CHD –Coronary Heart disease

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Obesity –HSE.ie

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Coronary Heart Disease -CHD

  • The heart blood supply –coronary artery.
  • CHD results when this artery becomes blocked.
  • Cholesterol builds on walls of artery and causes artery to become narrower.
  • Cholesterol levels rise from too much saturated fat and hydrogenated fat (trans) in the diet.

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Effects of heat on lipids:

Melting point:

Solid fats melt at 30-40°C

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Boiling point:

Lipids boil at high temperature 175-295 °C

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Effects of heat on lipids continued….

  • Smoke point: Fats and oils start to decompose when over- heated. They produce a blue haze known as acrolein or smoke. Smoke point occurs at 200°C (fats) and 250°C in oils

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  • Flash point:
  • Extreme over heating can cause the lipid to catch fire this is known as flash point. Flash point occurs at 310 °C (fats) and 325 °C (oils).
  • https://www.youtube.com/watch?v=O7q5mFi8h5w

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Properties of lipids:

  • Lipids have the ability to form an emulsion.
  • An emulsion: Solution formed when two liquids that do not usually mix, such as oil and water are forced to do so.

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Emulsions can be described as:

Water-in-oil emulsions:

  • Water droplets are dispersed in the oil e.g. butter, margarine

Oil-in-water emulsions:

  • Oil droplets are dispersed in water e.g. milk, mayonnaise

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Formed by vigorous shaking e.g. oil and vinegar in vinaigrette dressing.

Formed with the help of an emulsifier e.g. lecithin in egg yolk acts as an emulsifier in mayonnaise preventing water in eggs separating from oil.

Temporary emulsion:

Permanent emulsions

Type of emulsification

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https://create.kahoot.it/details/9647e48a-c8cc-4e22-971c-810d48a2d048

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KWL