Plant oils and their uses SPEC Flashcards
Where can vegetable oil be extracted from?
fruits, seeds and nuts
What two methods are used to extract vegetable oils?
plant material crushed
oil removed by pressing
water + impurities removed
distillation
water + impurities removed
Why are vegetable oils important foods?
A lot of energy
nutrients
Why are vegetable oils important fuels?
Give one example of biofuel made from vegetable oil
Release a lot of energy when burn in air
Biodiesel
Advantage + disadvantage of cooking food with oil instead of water
Ad: higher boiling points
–>cook foods at higher temperatures tha by boiling
–> quicker cooking
different flavours
Dis: increases energy food
releases when eaten
How are emulsions made?
Shaking water with oils
Tiny droplets formed that slow to seperate
Properties and uses of emulsions
thicker than oil/water
have many uses, depend on their special properties.
better texture
coating ability
appearance
salad dressings,
ice creams,
cosmetics
paints
What are emulsifiers?
Substances that help stop oil + water from seperating into layers
Keep emulsions stable
How does shaking emulsifier with emulsion make the emulsion more stable?
shaking breaks mixtures into tiny droplets that do not mix
hydrophilic head - attract to water droplets
hydrophobic tail - attract to oil droplets
Why are some vegetable oils described and unsaturated and how do u test this?
double carbon–carbon bonds
bromine water turns colourless
What is meant by hardening vegetable oils?
hydrogen
nickel catalyst
abt 60C
Hydrogen adds to the carbon–carbon double
bonds –> oil turns more saturated
How are hydrogenated oils useful?
saturated higher melting points solids room temperature useful as spreads \+ in cakes and pastries
