Plants and Oils Flashcards
Vegetable oils
Properties of food compared to coking with water
Oils extracted from plants, such as oilseed rape, that can be used as biofuels and foods.
Properties
Higher boiling points than water
Cooks food quicker
Gives food different flavour
Makes food crispier
Distillation
A method of extracting plant oils by evaporating them and then condensing them. Water and impurities are also removed.
Pressing
A method of extracting plant oils by crushing fruits, seeds or nuts. Water and impurities are also removed.
Hydrogenated oils
Oils that have been reacted with hydrogen gas (and a nickel catalyst) to make them a solid at room temperature.
Emulsion
When oils and water droplets are dispersed (spread out) in each other.
Emulsifier
A substance that stops oil and water separating out into layers.
Hydrophobic
The ‘tail’ part of the emulsifier molecule that is attracted to oil.
Hydrophilic
The charged ‘head’ part of an emulsifier molecule that is attracted to water.
Unsaturated oils
Vegetable oils that contain double carbon-carbon bonds.
Can be detected with bromine water - more bromine water = more double bonds.
Hydrogenation of unsaturated oils
Unsaturated oil can be hardened by reacting them with hydrogen in presence of nickel catalyst at 60C. These are called hydrogenated fats
Hydrogenated oils properties
Properties
Solid at room temperature
Higher melting points
Useful in spreads and in cakes
