Plants Flashcards
(18 cards)
What are plant oils extracted for ?
These oils can be extracted and used for food or for fuel.
Fruits and seeds contain a pot of oil, give a few examples of them.
Avocados and olives are oily fruits. Brazil nuts,peanuts and sesame seeds are oily seeds ( a nut is just a big seed really ).
How do you get the oil out of the plant material?
The plant material is crushed, pressed between metal plates and the oil is squashed out. This is the traditional method of making olive oil. Oil can be separated from the crushed plant material by a centrifuge or solvents. Distillation refines oil,and removes water, solvents and impurities.
3 facts on vegetable oils used in food
1) vegetable oils provide a lot of energy
2) there are other nutrients. Eg. Oils from seeds contain vitamin E
3) they also contain essential fatty acids , which the body needs for metabolic processes.
3 facts on vegetable oil and the benefits of cooking with it.
1) they have higher boiling points
2) adds flavour
3) increases energy in food
3 facts on vegetable oils and fuels
1)vegetable oils such as rapeseed and soybean oil can be processed and turned into fuels
2)provide a lot of energy so suitable for use as fuels
3)can make biodiesel- has similar properties to normal
Diesel and burns in the sans way.
True or false : oils and fats contain long-molecules with lots of carbon atoms
True
Continue the sentence : oils and fats are either _______ or _______.
Saturated
Unsaturated
Unsaturated oils contain what ?
Double bonds between some of the carbon atoms in their carbon chains. So unsaturated oil will decolourise bromine water.
Monounsaturated and polyunsaturated ?
Monounsaturated fats contain one c=c double bond in their carbon chains. Polyunsaturated contain more than one c=c double bond.
Can unsaturated oils be hydrogenated?
Yes
What state are unsaturated vegetable oils in at room temperature?
A liquid form/state
How can hydrogenated oils be harden?
They can be hardened by reacting them with hydrogen in the presence of a nickel catalyst at about 60°. This is called hydrogenation. hydrogen reacts with the double bond carbons and opens out the double bonds.
Do hydrogenated oils have high melting points than unsaturated oils?
Yes, they’re more solid at room temperature. This makes them useful as spread and for baking cakes and pastries.
your fault: is margarine partially hydrogenated vegetable oil?
Margarine is usually made from partially hydrogenated vegetable oils – turning all the double bonds in vegetable oil to single bonds would make margarine too hard and difficult to spread. Hydrogenating most of them gives margarine a nice, buttery, spreadable consistency.
The good things about partially Hydrogenerated vegetable oils
Partially hydrogenated vegetable oils are often used instead of butter and processed foods, e.g. biscuits. These oils are a lot cheaper than butter and keep longer. This makes biscuit cheaper and gives them a longer shelf life .
The bad things about hydrogenated oils
Partially hydrogenated vegetable oil means you end up with a lot of so-called trans-fats. And there’s evidence to suggest that trans-fats are very bad for you.
Vegetable oils in foods and health
1) vegetable oils tend to be unsaturated, well animal fats tend to be saturated
2) in general, saturated fats are less healthy than unsaturated fats ( as saturated fats increase the amount of cholesterol in the blood, which can block up the arteries and increase the risk of heart disease).
3) natural unsaturated fats such as olive oil sunflower oil reduce the amount of blood cholesterol. But because of the trans-fats, partially hydrogenated oil increases the amount of cholesterol in the blood. So eating a lot of feeds made with partially hydrogenated vegetable oils can actually increase the risk of heart disease.
4) cooking food in oil, whether saturated, unsaturated or partially hydrogenated, makes it more fattening.
