C1.6 Plant oils and their uses Flashcards
From which parts of the plants can oil be extracted from? (3)
Fruits, seeds and nuts
How are plant oils obtained? (3)
Plant material CRUSHED
Oil removed by PRESSING (or sometimes distillation)
Water and other impurities are removed
What are the two important uses of vegetable oils and why are they good for this?
Foods and FUELS because they provide a lot of ENERGY
FOOD because they provide us with NUTRIENTS
What is the main difference between vegetable oils and water? What is the advantage of this?
- V. oils have higher boiling points than water
- And can cook foods at higher temps than by boiling
What does cooking with vegetable oils at high temperatures do to the food? (3)
- Quicker cooking
- Different flavours
- Increases the energy that the food releases when eaten
Why can oils be used to produce emulsions?
Because they do not dissolve in water
Emulsions are thicker than oil and water. What do they provide in the products that they are added to? (3)
Better texture, coating ability and appearance
Give four examples of uses of emulsions
Salad dressings, ice creams, cosmetics and paints
What two properties do emulsions have towards water? (e.g. in the head and in the tail)
Hydrophilic head
Hydrophobic tail
What kind of bonds do vegetable oils that are unsaturated contain?
Double carbon-carbon bonds
How can unsaturated vegetable oils be hardened? What does this do to the bonds?
- By reacting with HYDROGEN in the presence of a NICKEL catalyst at about 60 °C
- H adds to the double C bonds
Why are hydrogenated oils solids at room temperature? What can they be used for because of this?
- Have higher melting points (than unhydrogenated)
- Spreads and in cakes and pastries
Which domestic product are vegetable oils hardened to make?
Margarine
Vegetable oils can make food as well as fuel. Name a fuel that it can make.
Biodiesel fuel
