1. Higher Chemistry Kitchen Chemistry - Food
NEW LEARNING
Fats and oils
Proteins
REVISION
Homologous series, Carbohydrates and Fuels

2. Starter Task p17 Food Groups
In order to be healthy it is important that we eat a balanced diet. This includes carbohydrates, fats & oils, proteins, vitamins, minerals, fibre and water.
Activity 2.17: Using a variety of sources, including consumer packaging, identify the recommended proportions of food sources for a balanced healthy diet:
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3. Lesson 1: Carbohydrates
Today we will learn to
Identify the chemical differences between the food groups.
We will do this by
Reviewing National 5 knowledge of carbohydrates and identifying the other groups.
We will have succeeded if
We can state the chemical make up and properties of carbohydrates.

4. Simple Sugars
Energy drinks need to be able to deliver a large dose of energy to the consumer. They do this by using the chemical glucose, a carbohydrate with the chemical formula C6H12O6. Glucose is found in many everyday products particularly sweets.
When glucose burns it produces carbon dioxide and water, this is because it is a carbohydrate, a compound containing just carbon, hydrogen and oxygen.

5. Simple Sugars (Mono and Disaccharides)
Glucose (monosaccharide) is a white powder and like sucrose (disaccharide) is used as both a sweetener and source of energy as we have already seen.
There are various tests for carbohydrates which we learned at Nat 5 – can you remember the similarities and differences between sucrose and glucose?

6. Starch and Polysaccharides
Bread and pasta are two very common foodstuffs that we use as a source of energy. Like glucose and sucrose they are both made of carbohydrates, but in bread and pasta the carbohydrate is called starch.
Plants convert glucose, made through photosynthesis, into starch through a condensation reaction, similar to the way sucrose is made in sugarcane. Whereas sucrose is a disaccharide, starch is a polysaccharide made up of thousands of glucose molecules all joined together.
What would be the result if we tested the following foodstuffs for starch?

7. Food Groups

8. Describe a key word without using that word (it is taboo!).
Glucose
Starch
Carbohydrate
Disaccharide

9. Starter Task
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10. Lesson 2: Fats and Oils Today we will learn to
Identify some sources of fats and oils and explain the difference between a fat and an oil.
We will do this by
Investigating different foodstuffs and drawing structures for fats and oils.
We will have succeeded if
We can explain why cod liver oil is a liquid and lard is a solid!

11. Fats and Oils p18 Fats & Oils
Fats and oils are an essential part of our diet, as they are a more concentrated source of energy compared to carbohydrates and provide essential fatty acids. They are also necessary in order to transport and store fat soluble vitamins. Fats and oils are a very good source of energy.
There are three sources of fats and oils; plant, animal and marine.
Activity 2.19: Look at a selection of fats and oils from vegetable, animal and marine sources.
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12. Fats and Oils
Natural fats and oils can be classified according to their origin as animal, vegetable or marine.
Animal
Vegetable
Marine
Beef fat (suet)
Sunflower oil
Cod liver oil
Pork fat (lard)
Olive oil
Tuna fish oil
Sheep fat
Linseed oil
Whale oil
Butterfat
Palm oil
Halibut liver oil

13. Fats and Oils in the Diet
Fats and oils in the diet supply the body with energy and are a more concentrated source of energy than carbohydrates e.g. bread flour (mostly carbohydrate)
Fats and oils are essential for the transport and storage of fat soluble vitamins in the body. Vitamins are divided into two groups: water-soluble (B-complex and C) and fat-soluble (A, D, E and K).

14. Fats and Oils
p19

15. Structure of Fats and Oils
Fats and oils are esters made when an alcohol, glycerol (with 3 hydroxyl groups) condenses with carboxylic acids known as fatty acids. Glycerol (propane-1,2,3-triol) is a trihydric alcohol.
The reaction between three fatty acids and glycerol is shown below. Each molecule of the alcohol condenses with 3 molecules of fatty acid.

16. Structure of Fatty Acids
Fatty acids are saturated or unsaturated straight-chain carboxylic acids containing even numbers of carbon atoms ranging from C4 to C24, primarily C16 and C18.
Fatty acid
Molecular formula
Saturated/Unsaturated
Butanoic acid
C3H7COOH
Saturated
Stearic acid
C17H35COOH
Oleic acid
C17H33COOH
Unsaturated
Linoleic acid
C17H31COOH

17. Fats and Oils
p19

18. Degree of Unsaturation in Fats and Oils
When an oil is shaken with bromine water, the brown colour of bromine water is lost rapidly. This indicates the presence of double bonds in the oil molecules.
If a fat is dissolved in an organic solvent such as ethanol and then shaken with bromine water, no decolourisation occurs with some fats and only slight or slow decolourisation with others. This indicates that fats may contain no double bonds or fewer double bonds than oils.

19. Melting Points of Fats and Oils
The lower melting points of oils compared to those of fats is related to the higher unsaturation of oil molecules.
The presence of double bonds in oil molecules causes the long chains of atoms to become distorted. This stops the oil molecules packing as closely together as the more saturated fat molecules can.

20. The poorer packing means less London dispersion forces can form between the oil molecules than between fat molecules. Less heat energy is needed to separate oil molecules and oils have lower melting points than fats.

21. Pyramid Question you have about the lesson
Things you have been reminded of today
Things you have learned today

22. Starter Task
Fats have higher melting points than oils because comparing fats to oils;
A Fats have more hydrogen bonds
B Fat molecules are more saturated
C Fat molecules are more loosely packed
D Fats have more cross-links between their molecules.
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23. Starter Task
Fats and oils are ester molecules known as triglcerides. The structure of a fat molecule is shown below
a)When this triglyceride is hydrolysed, a fatty acid is obtained. Name the other product obtained in this reaction.
(1)
b)Oils are liquid at room temperature; fats are solids. Why do oils have lower melting points than fats.
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24. Lesson 3: Proteins Today we will learn to
Describe the structure and function of proteins
We will do this by
Building molymods of amino acids and combining them into a protein.
We will have succeeded if
We can identify an amino acid from the functional groups present.

25. Protein Function
p20

26. Protein Function
Proteins are large, important and complex molecules (polymers) found in our bodies
They are involved in most reactions in cells.

27. Protein Function Each protein within the body has a specific function.
The main functions of proteins in the body are structural, maintenance and regulation of life processes (e.g haemoglobin carries oxygen)

28. Amino Acids
p20
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29. Amino acids
Proteins are constructed from building blocks called amino acids.
Amino acid molecules have two functional groups
carboxyl group (-COOH)
amino group (-NH2)

30. essential amino acids
The body cannot make all the amino acids required for body proteins and is dependent on dietary protein for supply of 22 certain amino acids known as essential amino acids.
E.g Glycine and glutamic acid:

31. Peptide Links
p21
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32. Amide Links (Peptide Links)
The link which forms between the two amino acids is called an amide link (CONH) (also known as a peptide link).
Amide (peptide) link

33. Condensation Reactions
The amino group on one amino acid and the carboxyl group on a neighbouring amino acid molecule join together, with the elimination of water.

34. Protein Types
p21
There are two types of protein structure globular and fibrous. Globular proteins form complex shapes, with the chain coiled around itself, held in position by weak forces of attraction such as hydrogen bonding. Globular proteins are often water soluble. Fibrous proteins are made of long straight chains tightly packed together forming solid structures that are insoluble.
DISCUSS
After discussion with your teacher and others can you explain how amino acids join together with peptide links to form long protein chains and describe the two types of protein structure and give examples of these in the human body.
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35. Protein Types Proteins can be classified as fibrous or globular
this structure is driven by hydrogen bonding within the protein molecule.

36. Protein Types
Protein type
Nature of protein
Examples
Function
Structural protein
Fibrous
Keratin
Protection of hair
Collagen and elastin
Support for tendons and ligaments
Contractile protein
Actin and myosin
Movement of muscles
Hormones
Globular
Insulin
Glucose regulation
Enzymes
Amylase
Digestion of carbohydrates
Transport protein
Haemoglobin
Oxygen transport in the blood
Antibodies
Made naturally in the body or after vaccination
Fighting disease
These proteins are specific to the body’s needs and are built up within the body by many condensation reactions of various amino acids.

37. Back to Plenaries
Definition
Choose three new words you have learnt today or in the last few lessons and write dictionary definitions.

38. Starter Task
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39. Starter Task
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40. Starter Task
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41. Lesson 4: Hydrolysis of Proteins
Today we will learn to
Break proteins back into their amino acids.
We will do this by
Learning about digestion and analysing some amino acids by chromatography.
We will have succeeded if
We use chromatography results to identify the amino acids in a protein.

42. Hydrolysis of Proteins

43. Digestion of proteins
Proteins obtained by eating plants or animals are broken up during digestion by a process called hydrolysis to produce amino acids.

44. Digestion of proteins
You can work out the structural formulae of the amino acids obtained from hydrolysis by looking at the structure of a section of the protein.

45. Hydrolysis of Proteins

46. Objective Traffic Lights
How do you feel about the lesson objectives?
Red = don’t think I have grasped this
Amber = feeling OK about this, have just about got there
Green = Confident I have achieved this
If there are no coloured cards available (e.g. in planners), Mark corners in the room for each colour and ask pupils to move to indicate confidence.

47. Starter Task
Complete Quick Test 3 and we will review as a class. You have 5 minutes!
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48. Starter Answers
Quick Test 3 D B C
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49. Lesson 5: Flavour and Cooking
Today we will learn to
Identify how flavour is affected by smell and chemical structure.
We will do this by
Experimenting with smell and taste and reviewing ‘volatility’.
We will have succeeded if
We can explain flavour, smell and solubility based on structure and bonding.

50. Flavour and Cooking
p24

51. Flavour and Cooking
p24

52. Flavours in Food
Many of the flavours in foods are due to the presence of volatile molecules.
Many flavour and aroma molecules belong to the family of esters, aldehydes or ketones (see later) so are carbonyl compounds.
Short carbonyl molecules can evaporate easily because of the lack of intermolecular forces – no H bonding and weak London Dispersion forces.
The toxicity of aldehydes, however, can result in unfortunate symptoms such as severe headaches.

53. Flavours in Food ACTIVITY 2.25: Flavour Testing Activity.
Your teacher may allow you to taste different foods with your nose blocked to see if you can identify them. Then unblock your nose to get the true taste.

54. Back to Plenaries
Definition
Choose three new words you have learnt today or in the last few lessons and write dictionary definitions.

55. Starter Questions
The following molecules are found in herbicides Which of the following contain an amide link?
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56. Starter Questions Draw 3 glycine molecules joined together.
The amino acid glycine has the following structure
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Draw 3 glycine molecules joined together.

57. Lesson 6: Cooking Food Today we will learn to
Identify the effect of cooking on some common ingredients.
We will do this by
Investigating the structure of proteins and alcohols, and what happens to them after cooking.
We will have succeeded if
We can use the terms denature, primary, secondary and tertiary correctly.

58. Cooking Food p25 Effect of Cooking Food
Within proteins, the long chain molecules may be twisted to form spirals, folded into sheets, or wound around to form other complex shapes. The chains are held in these forms by intermolecular bonding between the side chains of the constituent amino acids. When proteins are heated, during cooking, these intermolecular bonds are broken allowing the proteins to change shape (denature). These changes alter the texture of foods.

59. Proteins
Proteins are complex molecules made from long, amino acid chains which are also branched.
The chains are held together by intermolecular bonding between the side chains of the constituent amino acids.
Hydrogen bonds occur between the amide links and between other groups present in the molecule.
Proteins form three-dimensional structures which are sheets, spirals or coils.

60. Cooking Proteins
When proteins are heated, during cooking, these intermolecular bonds are broken allowing the proteins to change shape (denature).
These changes alter the texture of foods.
For example, egg whites contain many molecules of a globular protein called albumen. When an egg is boiled or fried, the protein structure is irreversibly changed and a solid is made.

61. Oxidation of Food and Drinks
p25
Alcohols can be classed as either primary, secondary or tertiary depending upon where in the structure the hydroxyl functional group is. If the hydroxyl group is attached to an end carbon it is a primary alcohol; if the hydroxyl group is attached to a carbon atom in the middle of a straight chain it is a secondary alcohol and if the hydroxyl group is attached to a carbon atom in the middle of a branched chain it is a tertiary alcohol:

62. Classification of Alcohols
Primary Alcohols (1°) – the carbon atom to which the hydroxyl group is attached to is bonded to no more than one other carbon. The other bonds are to hydrogen atoms.
Secondary Alcohols (2°) – the carbon atom to which the hydroxyl group is attached to is bonded to two other carbon atoms. Only one bond is to a hydrogen atom.
Tertiary Alcohols (3°) – the carbon atom to which the hydroxyl group is attached to is bonded to three other carbon atoms. There are no bonds to hydrogen atoms.

64. Pyramid Question you have about the lesson
Things you have been reminded of today
Things you have learned today

65. Starter Task
Complete Quick Test 4 and we will review as a class. You have 5 minutes!
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66. StarterTask Answers 1a. Water soluble 1b. Oil soluble
1c. Water soluble
2a Tertiary
2b. Primary
2c. Secondary
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67. Lesson 7: Oxidising Alcohols
Today we will learn to
Predict whether an alcohol will be oxidised or not from its structure.
We will do this by
Experimenting using potassium dichromate and hot copper oxide.
We will have succeeded if
We can correctly identify which alcohols will be oxidised and what they will form.

68. Oxidising Alcohols Activity 2.27 Oxidation of alcohols
Goggles to be worn at all times
Be aware of ties and long hair
Be aware of flammable nature of alcohols
Clean up spills immediately with a damp tissue
Method:
Place 1cm depth of each alcohol into three separate test tubes.
Add 5 drops of acidified potassium dichromate solution into each.
Place in a beaker containing boiling water and leave for 5 minutes.
Note the colour change from orange to pale green for those alcohols that have been oxidised.

69. Oxidising Alcohols

70. Oxidising Alcohols

71. Aldehydes and Ketones
Aldehydes and ketones both contain the carbonyl functional group, >C=O.
Aldehydes based on the alkane hydrocarbons are called alkanals and the -al ending identifies the substance as an aldehyde. They have the functional group -CHO.
Ketones which are based on the alkane hydrocarbons are called alkanones and the -one ending identifies the substance as a ketone. Ketones all have the >C=O group.

72. My Word!
Choose a word related to the lesson. You must stand up and point to someone in the class who must then give the meaning. That person then chooses the next person to pose a word.

73. Lesson 8: Further Oxidation
Today we will learn to
Name aldehydes and ketones and identify them using chemical tests.
We will do this by
Using Benedict’s/Fehiling’s solution and the ‘silver mirror’ test.
We will have succeeded if
We can correctly differentiate between aldehydes and ketones using chemistry!

74. Further Oxidation Naming Aldehydes & Ketones
There are many types of carbonyls with different structures and uses, but all have the same feature or functional group . A carbonyl group consists of an oxygen attached to the carbon chain with a double bond (O=C). If the carbonyl is at the end of the chain it is an aldehyde, if the carbonyl is anywhere else along the chain it is a ketone. If the carbon chains are alkanes then the aldehyde and ketones become members of the alkanal and alkanone homologous series respectively.
Activity 2.29: If you have Molymod kits your teacher may get you to make some of the first four members of the alkanal & alkanone homologous series.

75. Further Oxidation Further Oxidation
Aldehydes can undergo further oxidation using the same oxidising agents as before i.e. hot copper oxide or acidified potassium dichromate. You can also use Tollen’s reagent or Benedicts (Fehlings) reagent; ketones cannot react and therefore this reaction can act as a test for aldehydes or ketones.

76. Naming Again! Ketones Aldehydes
You will be expected to name straight-chain and branched-chain ketones, with no more than eight carbon atoms in their longest chain from structural formulae. You will also be expected to draw structural formulae and write molecular formulae given the names of straight-chain or branched-chain ketones.
Aldehydes
You will be expected to name straight-chain and branched-chain aldehydes, with no more than eight carbon atoms in their longest chain from structural formulae. You will also be expected to draw structural formulae and write molecular formulae given the names of straight-chain or branched-chain aldehydes.

77. Further Oxidation

78. Oxidation of Aldehydes and Ketones
Oxidising agents such as copper (II) oxide, Fehling's (or Benedict's) solution, acidified potassium dichromate or Tollen's reagents will convert aldehydes to carboxylic acids
The reaction is classed as an oxidation because of an increase in the oxidation: hydrogen ratio.
Ketones do not undergo oxidation and this fact can be used to distinguish aldehydes from ketones.

79. Oxidising Agents Reagent Aldehyde Ketone Copper(II) oxide
Black to Red-Brown
No change
Acidified Potassium Dichromate
Orange to Green/Blue
Fehling's (or Benedict's) solution
Blue to Red-Brown
Tollen's reagent
Colourless to Silver

80. Helpful Tips
Write 5 top tips or golden rules about the topic for students taking the lesson next year.

81. Whiteboards Starter

82. Antioxidants Antioxidants
Oxygen reacts with edible oils giving the food a rancid flavour. Antioxidants are molecules which will prevent these oxidation reactions taking place. They do this by being oxidized themselves, so antioxidants are often good reducing agents .
Vitamin C is also called ascorbic acid and is thought to act as an antioxidant in the body.
Ascorbic acid is a good reducing agent as it is readily oxidised itself:
C6H8O6 à C6H6O6 + 2H e-
Activity 2.31: Brown Apples
Your teacher may get you to set up an experiment to find which fruit juice is best at preventing apples from going brown, a process caused by oxidation.
Many fruits, vegetables and teas contain antioxidants and are believed by many to have beneficial health effects.

83. Researching Chemistry Unit
Antioxidants
Researching Chemistry Unit