1.6 Plant And Vegetable Oils Flashcards
What are rich in oils?
Fruits, seeds and nuts
What two ways can oils be extracted from seeds?
Cold pressing
Distillation
What is cold pressing?
You crush the seeds together at under 40 degrees and oil should be extracted
You will then need to filter it
How is distillation used to extract oil from seeds?
You heat the seeds with water just underneath them and eventually water vapour and oil is carried upwards
It condenses in the tube and collects at the bottom
You separate the water vapour and oil in a separating funnel
Why are vegetable oils important foods and fuels?
They provide a lot of energy and nutrients
Do vegetable oils have a high or low boiling point?
High boiling point
Why do vegetable oils have a high boiling point?
They have strong intermolecular forces
What does the high boiling point of vegetable oils result in?
Quicker cooking
Better flavour
Increases energy released when eaten (not good for health)
What is a property of plant and vegetable oils?
Either
unsaturated - one carbon double bond
Or
Polyunsaturated - more than one carbon double bond
Why are animal fats and oils more unhealthy?
Saturated
They have many branches in the carbon chain
They clog arteries therefore increase cholesterol
What state is a fat at room temperature?
Solid
What state is an oil at room temperature?
A liquid
How do you created hydrogenated oils?
You react an unsaturated fat with hydrogen and a nickel catalyst at 60-65 degrees
What does hydrogen do when you react it with an unsaturated fat?
Hydrogen breaks the carbon double bond
What properties do hydrogenated oils have?
Higher melting points
Solids at room temperature (margarine)
What is an emulsion?
Produced when two immiscible liquids are mixed together with an emulsifier
What is immiscible?
Incapable of being mixed or blended
What is an emulsifier? What does it do?
A chemical added to an emulsion to stop it separating
It stabilises the emulsion
Why don’t water and oil mix?
They have different types of bonding
Therefore they are immiscible
Describe an emulsifier?
It has two ends
Hydrophobic - repels water
Hydrophilic- attracts water
What are some properties of emulsions?
Thicker
Better texture
Better taste
Nicer appearance
Give some examples of emulsions?
Salad dressings
Ice cream
Cosmetics
Paint
