“C1.6 Plant Oils” Ks4 Science 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 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. Vegetable oils are important foods and fuels as they provide a lot of energy. They also provide us with nutrients. 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.

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 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. HT only Emulsifiers have hydrophilic and hydrophobic properties.

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) Standard Demand (B-D) High Demand (A*-B) Keywords: unsaturated, vegetable oil, kJ (kilo joule = 1000J), bromine water

Plant Oils? Veg Oil Coumarin is a benzopyrone that occurs naturally in plant-derived sources such as, lavender oil, Olive Oil or 4-hydroxyphenethyl 4-formyl-3-(2-oxoethyl)hex-4-enoate

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

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

a) Some fruits, seeds and nuts are rich in oils that can be extracted 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.

a) Some fruits, seeds and nuts are rich in oils that can be extracted 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.

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”

Practical Test.... To go …..“colourless”

Extra Help on Task... Solvent Extraction: Steam Distillation: Germanium Oil: http://www.youtube.com/watch?v=gDojS7PWWPY Maceration: Cold Pressing: Olive Oil: http://www.youtube.com/watch?v=qiK5DF1NvGs

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.

Chemistry C1 6.1 Extracting vegetable oil Answers to in-text questions 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.

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

Read p88 C1 6.2 “Cooking with vegetable oils” independently (LD) 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. START END PA Teacher Introduction SA Answer Q2, 3 p89 (HD) Answer Q a,b,c & Q1, p89 (SD) PA Read p89 then explain with a diagram How do we turn vegetable oils into spreads. (H) Read p88 C1 6.2 “Cooking with vegetable oils” independently (LD) Write a paragraph to explain what are the advantages and disadvantages of cooking with vegetable oils (SD) PA Read p89 write a comparison HSW article about if we should or should not hydrogenate vegetable oils (H) Use a diagram to explain What are the advantages and disadvantages of cooking with vegetable oils (LD) TA PA Extension: teach another student the idea of hardening with a nickel catalyst. PA Low Demand (E-G) Standard Demand (B-D) High Demand (A*-B) TA = Teacher Assessed SA = Self Assessed PA = Peer Assessed

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.

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)

Student – “Self Assessed” 6.2 Quick Review... Student – “Self Assessed” Statements about vegetable oils... Score /7

Everyday Emulsions (page 90) C16.3 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

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

True or False – End Lesson 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. START END Teacher Introduction “Emulsions” PA Use the idea of hydrophobic and hydrophilic to explain why emulsions work. (HD) SA Answer Qa,b Q1,2 (SD) Read p90/91 C1 6.3 “Everyday Emulsions” independently (LD) Write a paragraph and draw a diagram to explain what an emulsion is (SD) Extension: Design your own practical to investigate emulsions of cooking oil and water. Create a “perfect method” SD-HD Use a diagram to show what an emulsion is. (LD) PA TA SA Low Demand (E-G) Standard Demand (B-D) High Demand (A*-B) True or False – End Lesson TA = Teacher Assessed SA = Self Assessed PA = Peer Assessed

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.

6.3 Emulsions Quick Review... Student – “Self Assessed” Score /8

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.

Food Issues (page 92) C16.4 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,

Food Issues – Article (Foundation) 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. For example the UK Food Standards Agency (FSA) has strict limits on the amount of colourings (e-numbers) allowed in food. Some additives can lead people to have allergic reactions to them, and colourings are banned from use in baby foods. E-Numbers FSA

True or False – End Lesson b) Vegetable oils are important foods and fuels as they provide a lot of energy. They also provide us with nutrients. START END PA Teacher Introduction “Food Issues” PA Write a detailed paragraph about the use of additives to create emulsions(SD) P93 Do Activity 3 (HD) Read p92/93 C1 6.4 “Food Issues” independently (LD) Answer Q2b p93 (HD) PA SA Answer Qa,b Q1,2a (SD) 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 PA Write a simple paragraph to explain the idea of additives. (LD) P93 do activity 1 or 2 (SD) TA PA SA Low Demand (E-G) Standard Demand (B-D) High Demand (A*-B) True or False – End Lesson TA = Teacher Assessed SA = Self Assessed PA = Peer Assessed

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.

type of additive example typical use Extra Information type of additive example typical use colouring tartrazine (E102) orange colouring for soft drinks, sweets and sauces emulsifier 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 micro-organisms growing sweetener Aspartame (E951) low-calorie drinks and food

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 to provide plenty of energy for exercise. Higher in unsaturated fats which protect against heart disease. Have a high energy value which can turn to fat if you do not do enough exercise. Hydrogenated vegetable oils contain trans-fat, which has been associated with 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.