C1.6-Plant-Oils

Report
“C1.6 Plant Oils”
Mr Powell 2013
Syllabus...
C1.6 Plant oils and their uses Many plants produce useful oils that can be
converted into consumer products including processed foods. Emulsions can be
made and have a number of uses. Vegetable oils can be hardened to make
margarine. Biodiesel fuel can be produced from vegetable oils.
C1.6.1 Vegetable oils
a)
Some fruits, seeds and nuts are rich in oils that can be extracted. The
plant material is crushed and the oil removed by pressing or in some cases
by distillation. Water and other impurities are removed.
b) Vegetable oils are important foods and fuels as they provide a lot of
energy. They also provide us with nutrients.
c)
Vegetable oils have higher boiling points than water and so can be used to
cook foods at higher temperatures than by boiling. This produces quicker
cooking and different flavours but increases the energy that the food
produces when it is eaten.
Mr Powell 2013
Index
Syllabus...
C1.6 Plant oils and their uses Many plants produce useful oils that can be
converted into consumer products including processed foods. Emulsions can be
made and have a number of uses. Vegetable oils can be hardened to make
margarine. Biodiesel fuel can be produced from vegetable oils.
C1.6.2 Emulsions
a)
Oils do not dissolve in water. They can be used to produce emulsions.
Emulsions are thicker than oil or water and have many uses that depend
on their special properties. They provide better texture, coating ability
and appearance, for example in salad dressings, ice creams, cosmetics
and paints.
b) HT only Emulsifiers have hydrophilic and hydrophobic properties.
Mr Powell 2013
Index
C1
6.1
1.
2.
3.
Extracting Vegetable Oil (page 86)
Lesson Aims/ Levels
How do we extract oils from plants (L)
Why are vegetable oils important foods (S)
What are unsaturated oils and how do we detect them . (S/H)
Literacy: Written understanding using article and transferring information to a
new form.
Low Demand (E-G)
Keywords: unsaturated, vegetable oil, kJ (kilo joule
Standard Demand (B-D) = 1000J), bromine water
High Demand (A*-B)
Mr Powell 2013
Index
Plant Oils?
Veg Oil
Coumarin is a benzopyrone
that occurs naturally in plantderived sources such as,
lavender oil,
Olive Oil or 4-hydroxyphenethyl 4-formyl-3(2-oxoethyl)hex-4-enoate
Mr Powell 2013
Index
b) Vegetable oils are important foods and fuels as they provide a lot of energy.
They also provide us with nutrients.
•
The equipment was setup as shown in the
diagram.
•
Different fuels were burned to see how
much energy they contained.
•
A student recorded the change in
temperature of the water in the tine can.
•
They used the results to work out the
energy released by the two oils and found
that they were different.
•
Vegetable oil had 3900kJ per 100g
•
Sugar had 1700kJ per 100g
•
Animal Protein had 1100 per 100g
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Index
TASK & Criteria: Use the information in the article to explain how vegetable oils are
extracted. Your work should include something for each method. You may work in a
pair and discuss your work and ideas before you write your own piece..
Challenge Level
Student
Assessed?
Teacher
Assessed?
Low Demand: 2-4 simple diagrams of processes
with labels.
Standard Demand: 3-4 complex labelled and
explained diagrams of processes.
High Demand: 4 complex explained and labelled
diagrams of processes with comparison between
methods.
*/I
Mr Powell 2013
Index
a) Some fruits, seeds and nuts are rich in oils that can be extracted. The plant
material is crushed and the oil removed by pressing or in some cases by distillation.
Water and other impurities are removed.
1) Steam Distillation: Used mainly to extract essential oils from plants. The
plant material is placed into a still (very similar to a pressure cooker) where
pressurized steam passes through the plant material.
The heat from the steam causes globules of oil in the plant to burst and the oil
then evaporates. The essential oil vapour and the steam then pass out the top
of the still into a water cooled pipe where the vapours are condensed back to
liquids. At this point, the essential oil separates from the water and floats to the
top. Now, this doesn't sound like a particularly complicated process but did you
know that it takes more than 8 million Jasmine flowers to produce just 2 pounds
of jasmine oil? No wonder pure essential oils are expensive!
2) Maceration: Maceration actually creates more of an “infused oil" rather than
an "essential oil" and is most often used for creating extracts and resins. The
plant matter is soaked in vegetable oil, water, or another solvent. If it's soaked
in vegetable oil, and then heated and strained, it can be used for massage.
Soaked in water or another solvent such as alcohol will create a much thicker
extract or resin.
Mr Powell 2013
Index
a) Some fruits, seeds and nuts are rich in oils that can be extracted. The plant
material is crushed and the oil removed by pressing or in some cases by distillation.
Water and other impurities are removed.
3) Cold Pressing: Cold pressing is used to extract the essential oils from citrus
rinds such as orange, lemon, grapefruit and bergamot. The rinds are separated
from the fruit, are ground or chopped and are then pressed. The result is a
watery mixture of essential oil and liquid which will separate given time.
It is important to note that oils extracted using this method have a relatively
short shelf life, so make or purchase only what you will be using within the next
six months.
4) Solvent Extraction: A hydrocarbon solvent is added to the plant material to
help dissolve the essential oil. When the solution is filtered and concentrated by
distillation, a substance containing resin (resinoid), or a combination of wax and
essential oil (known as concrete) remains.
From the concentrate, pure alcohol is used to extract the oils or fats. When the
alcohol evaporates, the oil is left behind. This is not considered the best
method for extraction of essential oils, as the solvents can leave a heavy residue
behind, but it's great for making resins for this very reason.
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Index
What are unsaturated oils and how do we detect them . (S/H)
Bromine water (which is yellow/orange) reacts with C=C bonds when the
vegetable oil is unsaturated.
When partial hydrogenation takes place, there are still some C=C bonds left but
not as many, so it takes longer to decolourise the bromine water.
Once it has been completely hardened, the oil is saturated; there are no C=C
bonds, so no reaction occurs.
To go …..“colourless”
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Practical Test....
To go …..“colourless”
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Index
Extra Help on Task...
Solvent Extraction:
Steam Distillation:
Germanium Oil:
http://www.youtube.com/watch?v=gDoj
S7PWWPY
Maceration:
Cold Pressing:
Olive Oil:
http://www.youtube.com/watch?v=qiK5
DF1NvGs
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Index
Summary...
Fatty acids: long fatty acid chains stop vegetable oils
dissolving in water.
The fatty acids in some vegetable oils are saturated, and
only have single bonds between their carbon atoms.
Saturated oils tend to be solid at room temperature, and
are sometimes called vegetable fats instead of oils. Lard
is an example of a saturated oil.
The fatty acids in some vegetable oils are unsaturated,
and have double bonds between some of their carbon
atoms. Unsaturated oils tend to be liquid at room
temperature, and are useful for frying food. They can be
divided into two categories:
Monounsaturated fats have one double bond in each
fatty acid
Polyunsaturated fats have many double bonds.
Mr Powell 2013
Index
Chemistry C1 6.1
Answers to in-text questions
Extracting vegetable oil
a Pressing and (steam) distillation.
b The orange bromine water will be decolourised (turn colourless).
Summary answers
1 pressing (distillation), distillation (pressing), energy, unsaturated, bromine,
decolorised
2 Because vegetable oils contain a lot of energy, which becomes stored as fat in
the body if it is not used up.
3 Answer c – we can be certain that the sample contains unsaturated oils
because it decolorises bromine water but we cannot be certain whether or not it
contains saturated oils because these have no effect on bromine water.
Mr Powell 2013
Index
C1
6.2
1.
2.
3.
Cooking with Veg Oil (page 88)
Lesson Aims/ Levels
What are the advantages and disadvantages of cooking with vegetable oils
(L/S)
What does it mean when we harden vegetable oils (S/H)
How do we turn vegetable oils into spreads. (H)
Literacy:
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
Keywords: unsaturated, hardening or
hydrogenation
Mr Powell 2013
Index
c) Vegetable oils have higher boiling points than water and so can be used to cook
foods at higher temperatures than by boiling. This produces quicker cooking and
different flavours but increases the energy that the food produces when it is eaten.
Teacher
Introduction
Read p88 C1 6.2
“Cooking with
vegetable oils”
independently (LD)
Use a diagram to
explain What are the
advantages and
disadvantages of
PA
cooking with
vegetable oils (LD)
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
SA
Answer Q a,b,c &
Q1, p89 (SD)
Write a paragraph
to explain what are
the advantages and
disadvantages of
cooking with
vegetable oils (SD)
Answer Q2, 3 p89 (HD)
PA
Read p89 then explain PA
with a diagram How do
we turn vegetable oils into
spreads. (H)
Read p89 write a
comparison HSW article
about if we should or
should not hydrogenate
vegetable oils (H)
PA
TA
TA = Teacher Assessed
SA = Self Assessed
PA = Peer Assessed
Extension: teach another
student the idea of
hardening with a nickel
catalyst.
Mr Powell 2013
Index
PA
Hydrogenation – “Hardening”
Saturated vegetable fats are solid at room temperature, and
have a higher melting point than unsaturated oils.
This makes them suitable for making margarine, or for
commercial use in the making of cakes and pastry.
Unsaturated vegetable oils can be ‘hardened’ by reacting
them with hydrogen, a reaction called hydrogenation.
During hydrogenation, vegetable oils are reacted with
hydrogen gas at about 60ºC.
A nickel catalyst is used to speed up the reaction.
The double bonds are converted to single bonds in the
reaction.
In this way unsaturated fats can be made into saturated fats
– they are hardened.
Mr Powell 2013
Index
Chemistry C1 6.2
Cooking with vegetable oils
Answers to in-text questions
a The boiling point of vegetable oils is much higher.
b Food cooked in oil cooks more quickly. The outside often turns a different colour
and becomes crisper. The food absorbs some of the oil, which increases its energy
content.
c hardening
Summary answers
1 higher, tastes, water, energy
2 melting, hydrogen, hardening, nickel, hydrogenated (Higher)
3 a They have a higher melting point and can be used to make spreadable solids at
room temperature. (Higher)
b Heat the oil and hydrogen at 60 °C with a nickel catalyst. (Higher)
Mr Powell 2013
Index
6.2 Quick Review...
Student – “Self Assessed”
Statements about vegetable oils...
Score
/7
Mr Powell 2013
Index
C1
6.3
1.
2.
3.
Everyday Emulsions (page 90)
Lesson Aims/ Levels
What are emulsions and how do we make them? (L/S)
Why are emulsions made from vegetable oils so important? (L/S)
What is an emulsifier/ How does it work. ? (L-H)
HT Only: Emulsifiers have hydrophilic and hydrophobic properties.
Literacy:
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
Keywords: hydrophilic (loves water), hydrophobic
(hates water), emulsion, emulsifier, detergent,
immiscible
Mr Powell 2013
Index
a) Oils do not dissolve in water. They can be used to produce emulsions. Emulsions
are thicker than oil or water and have many uses that depend on their special
properties. They provide better texture, coating ability and appearance, for
example in salad dressings, ice creams, cosmetics and paints.
Emulsions: vegetable oils do not
dissolve in water. If a mixture of oil
and water is shaken, then left to
stand, eventually a layer of oil will
form on the surface of the water.
If an emulsifier is added to the oil
and water, a mixture called an
emulsion forms.
Emulsions are more viscous than
oil or water on their own, and
contain tiny droplets of one of the
liquids spread through the other
liquid.
Examples of oil droplets in water:
•
•
•
•
•
egg yolk
milk
ice cream
salad cream
Mayonnaise
Examples of water droplets in oil:
•
•
•
•
margarine
butter
skin cream
moisturising lotion
Mr Powell 2013
Index
a) Oils do not dissolve in water. They can be used to produce emulsions. Emulsions are thicker
than oil or water and have many uses that depend on their special properties. They provide
better texture, coating ability and appearance, for example in salad dressings, ice creams,
cosmetics and paints.
Teacher Introduction
SA
“Emulsions”
Answer Qa,b Q1,2
(SD)
Read p90/91 C1 6.3
“Everyday Emulsions”
independently (LD)
Use a diagram to
show what an
emulsion is. (LD)
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
Write a paragraph
and draw a diagram
to explain what an
emulsion is (SD)
PA
TA = Teacher Assessed
SA = Self Assessed
PA = Peer Assessed
Use the idea of
PA
hydrophobic and
hydrophilic to explain why
emulsions work. (HD)
Extension: Design your
own practical to
investigate emulsions of
cooking oil and water.
Create a “perfect method”
SD-HD
TA
True or False – End Lesson
Mr Powell 2013
Index
SA
b) HT only Emulsifiers have hydrophilic and hydrophobic properties.
Emulsifiers are molecules that have
two different ends:
a hydrophilic end - water-loving that forms chemical bonds with
water but not with oils
a hydrophobic end - water-hating that forms chemical bonds with oils
but not with water
Lecithin is an emulsifier commonly
used in foods.
It is obtained from oil seeds and is a
mixture of different substances.
A molecular model of one of these
substances is seen in the diagram.
The hydrophilic 'head' dissolves in the
water and the hydrophobic 'tail' dissolves
in the oil. In this way, the water and oil
droplets become unable to separate out.
The mixture formed is called an emulsion.
Mr Powell 2013
Index
6.3 Emulsions Quick Review...
Student – “Self Assessed”
Score
/8
Mr Powell 2013
Index
Chemistry C1 6.3
Everyday emulsions
Answers to in-text questions
a A substance that stops oil and water separating out into layers.
b It keeps the sauce thick and smooth.
Summary answers
1 mix, small, emulsion, separating, emulsifier, mayonnaise, ice, cosmetics
2 a Salad cream is thick (viscous) and is not transparent.
b To prevent the oil and water in the emulsion from separating out into layers.
3 The ‘tails’ of the emulsifier molecules dissolve into the oil, leaving ‘heads’ of the
molecules lining the surface of the oil droplet. These droplets then repel each other
and remain spread throughout the water.
Mr Powell 2013
Index
C1
6.4
1.
2.
Food Issues (page 92)
Lesson Aims/ Levels
What are the benefits and drawbacks of using emulsifiers in our food. (L-H)
What are the good and bad points about vegetable oils in our food. (L-H)
Literacy:
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
Keywords: vitamin, stabiliser, emulsifier, additive,
e-number,
Mr Powell 2013
Index
Food Issues – Article (Foundation)
1.
Processed foods, including vegetable oils, may have
chemicals added to them.
2.
These chemical additives have different jobs, including
extending a food product’s shelf life and improving its
taste and appearance.
3.
You can find additives listed on the ingredients label of
such foods, and many of these additives have E
numbers to identify them.
4.
Additives with an E number have been licensed by the
European Union.
5.
For example the UK Food Standards Agency (FSA) has
strict limits on the amount of colourings (e-numbers)
allowed in food.
6.
Some additives can lead people to have allergic
reactions to them, and colourings are banned from use
in baby foods.
Mr Powell 2013
Index
b) Vegetable oils are important foods and fuels as they provide a lot of energy. They
also provide us with nutrients.
Teacher Introduction
“Food Issues”
Read p92/93 C1 6.4
“Food Issues”
independently (LD)
Write a simple
paragraph to explain
the idea of additives.
(LD)
PA
Low Demand (E-G)
Standard Demand (B-D)
High Demand (A*-B)
Write a detailed
paragraph about
the use of additives
to create
emulsions(SD)
Answer Qa,b
Q1,2a (SD)
PA
P93 Do Activity 3 (HD)
Answer Q2b p93 (HD)
SA
PA
P93 do activity 1 or
2 (SD)
TA = Teacher Assessed
SA = Self Assessed
PA = Peer Assessed
PA
PA
Extension/ HW: Write down
a detailed account of the
problems of using Sudan 1 in
foods. Use the
internet/article from your
teacher as a resource
TA
True or False – End Lesson
Mr Powell 2013
Index
SA
Food Issues – Article (Higher)
As we have seen, processed foods, including vegetable oils, may have chemicals
added to them. These chemical additives have different jobs, including
extending a food product’s shelf life and improving its taste and appearance.
You can find additives listed on the ingredients label of such foods, and many of
these additives have E numbers to identify them.
Additives with an E number have been licensed by the European Union. Some
are natural and some are artificial, but they have all been tested for safety and
passed for use.
The UK Food Standards Agency (FSA) has strict limits on the amount of
colourings allowed in food. Some additives can lead people to have allergic
reactions to them, and colourings are banned from use in baby foods.
Food scares
A red dye called 'Sudan I' was quite recently banned for use in food, because it
was thought to be a health risk. Some of the dye had been used in chilli powder
before the ban came into force, and was later added in this form to some foods
by mistake. Hundreds of food items with this ingredient had to be taken off
supermarket shelves and destroyed as a result.
Mr Powell 2013
Index
Extra Information
type of additive
example
typical use
colouring
tartrazine (E102)
orange colouring for soft
drinks, sweets and sauces
lecithin (E322)
allows oil and water mix
to make margarine, ice
cream and salad cream
preservative
benzoic acid (E210)
used in many foods to
stop harmful microorganisms growing
sweetener
Aspartame (E951)
low-calorie drinks and
food
emulsifier
Mr Powell 2013
Index
Chemistry C1 6.4
Food issues
Answers to in-text questions
a A substance that is added to food to make it keep longer or to improve its taste
or appearance.
b vitamin E
Summary answers
1
Advantages of vegetable oils
Disadvantages of vegetable oils
Contain nutrients such as vitamin E.
Have a high energy value which can turn
to fat if you do not do enough exercise.
Have a high energy value to provide
plenty of energy for exercise.
Hydrogenated vegetable oils contain
trans-fat, which has been associated with
Higher in unsaturated fats which
heart disease.
protect against heart disease.
2 a For example, ice cream, chocolate, mayonnaise, salad cream, yoghurt.
b Emulsifiers enable oil and fats to be mixed in watery solutions without separating
out to give an oily layer on top or blobs of fat. They can make foods creamier and
thicker in texture which result in them being more tempting to eat.
Mr Powell 2013
Index

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