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C1 Plant Oils

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Vegetable Oils and Uses
Topic Quiz

Keywords

Distillation

A separating technique used to separate liquids based on their boiling points.


Unsaturated

A hydrocarbon is unsaturated if it contains any carbon-carbon double bonds.

Hydrogenation

The process of adding hydrogen across the carbon-carbon double bond in an unsaturated molecule. Also known as hardening.


Emulsion

A mixture of oil and water, where one of the two is suspended in the other. An emulsion will eventually separate, unless an emulsifier is present - these stabilise emulsions stopping them from separating.

Extraction

Oils from vegetables and plants, such as rapeseed, can be used to make biofuels. The methods you need to know about to extract these oils are:

  1. pressing the seeds and plants
  2. distillation to separate the oils from water

The video below contains lots of information that is relevant to the rest of the topic too.


Vegetable Oils

Vegetable oils consist of glycerol and fatty acids, but you do not need to worry about their specific structures for the exam.


Vegetable oils have a higher boiling point than water, meaning higher temperatures can be used for cooking. This means that food can be cooked faster than in water, and food will have different flavours if cooked with oil. Food cooked in oil will also release more energy when eaten, than if cooked in water - having health implications, and could lead to obesity.


Saturated vs Unsaturated

Fats are oils that are solid at room temperature, and are saturated.

Liquid fats (oils) are made up of unsaturated fats, and can be split into two groups:

  1. monounsaturated fats - one double bond
  2. polyunsaturated fats - several double bonds

Higher Tier

Unsaturated fats can be converted into saturated fats by a process called hydrogenation. The fats are 'hardened' using hydrogen gas and a nickel catalyst at about 60 degrees celcius.


Emulsions

An emulsion is a mixture of water with small droplets of oil (or the other way around). However over time, this mixture will start to separate out - as the two chemicals are immiscible.

Emulsifiers stabilise emulsions, stopping the mixture from separating. Examples of naturally occuring emulsifiers include: egg yolk and mustard.


Emulsifiers

Higher Tier

Emulsifiers have two parts:

  1. a 'water loving' head - hydrophilic
  2. a 'water hating' tail - hydrophobic

This molecule allows the oil and water to mix, where the hydrophilic head dissolves in water, and the hydrophobic tail dissolves in the oil.


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Page last updated: 16/04/2017