Researching Chemistry - Antioxidants Researching Chemistry consists of two assessment activities (assessed by your teacher): This will help you greatly when it comes to writing your assignment later (assessed by SQA). ASSESSMENT ACTIVITY 1- Literature research, including: More focused research surrounding the aim of your investigation. (2 sources required) Finding out about the Underlying Chemistry of antioxidants - you must keep a record of all your notes and of all sources you use. (2 sources required)

A plan of the practical investigation (including a clear aim, hypothesis, variables, method and risk assessment) A record of observations/measurements including labels and units (i.e. ALL raw data). The candidate should be observed to follow procedures safely. A full investigation write-up, including presenting findings in an appropriate format. Researching Chemistry - Antioxidants The raw data from Researching Chemistry will be used as data source 1 in your assignment. ASSESSMENT ACTIVITY 2- Practical research, including:

Introduction to antioxidants

Oxidative damage Oxidation reactions can produce free radicals. A free radical is a highly reactive species containing an unpaired electron. Free radicals can damage food (also plastics and living organisms) by removal of an electron. Antioxidant molecules ‘mop up’ free radicals to protect the foodstuff.

Damaging free radical Electron transferred Antioxidant/ free radical scavenger Antioxidant converted to a stable free radical Neutralised free radical Radical now in a stable pair How antioxidants work

How does an antioxidant cancel out a free radical? The antioxidant molecule is a free radical scavenger – it donates an electron to the potentially damaging free radical. A stable electron pair is formed, stabilising the free radical. The antioxidant itself becomes oxidised (loses an electron).

Antioxidants – short video clips Understanding antioxidants antioxidants work radical analogy antioxidants

Antioxidants in action Oxidation occurs when the apple is left exposed to air The apple is protected when dipped in orange juice containing the antioxidant vitamin C

Antioxidants Oxidation reactions happen when chemicals in the food are exposed to oxygen in the air. In natural conditions, animal and plant tissues contain their own antioxidants but in foods, these natural systems break down and oxidation is bound to follow. Oxidation of food is a destructive process, causing loss of nutritional value and changes in chemical composition. Oxidation of fats and oils leads to rancidity and, in fruits such as apples, it can result in the formation of compounds which discolour the fruit. Antioxidants are added to food to slow the rate of oxidation and, if used properly, they can extend the shelf life of the food in which they have been used.

Examples of antioxidants Vitamin C Melatonin Vitamin E  -carotene

Vitamin C (ascorbic acid) The antioxidant vitamin C can act as a reducing agent (electron donor), preventing oxidation (electron loss) from the foodstuff. C 6 H 8 O 6 C 6 H 6 O 6 + 2H + + 2e - Ascorbic acid Dehydroascorbic acid

This is a hormone which helps to regulate sleep in our bodies. This compound can be termed as a terminal or suicidal antioxidant as once it has removed the free radicals it has to be replaced. Melatonin

This is a form of vitamin E and can be found in vegetable oil, nuts and seeds. It has been suggested that it is good for the skin. α-tocopherol

Ascorbic acid is also known as Vitamin C and is commonly found in fruits and vegetables. It is one of the essential vitamins and the human body is unable to synthesize it. It can be easily oxidised and acts as a hydroxyl or superoxide anion free radical scavenger. Ascorbic Acid (Vitamin C)

β-carotene This is a precursor to vitamin A. It is a highly red-orange pigment found in plants and fruits. In particular it gives carrots their orange colour. It helps human cells to absorb vitamin A.

AntioxidantE-numberTypical foods Ascorbic acid (vitamin C) E300 Beers, cut fruits, jams, dried potato. Helps to prevent cut and pulped foods from going brown by preventing oxidation reactions that cause the discolouration. Can be added to foods, such as potato, to replace vitamin C lost in processing. Tocopherols (Vitamin E) E306 Oils, meat pies. Obtained from soya beans and maize. Reduces oxidation of fatty acids and some vitamins. Butylated hydroxyanisole (BHA) E320 Oils, margarine, cheese, crisps. Helps to prevent the reactions that break down fats and cause the food to go rancid. Citric acidE330 Jam, tinned fruit, biscuits, alcoholic drinks, cheese, dried soup. Naturally-occuring in citrus fruits like lemons. Helps to increase the anti-oxidant effects of other substances. Helps to reduce the reactions that can discolour fruits. May also be used to regulate pH in jams and jellies. Antioxidants as food additives

Impact of antioxidants on health The imbalance between free radicals and antioxidants can lead to disease and ill health. The 4 main non-enzymatic antioxidants metalonin, α-tocopherol (Vitamin E), ascorbic acid (Vitamin C) and β-carotene (precursor for Vitamin A) can be found in a range of foods in our diet. However medical opinions are divided as regards the impact these antioxidants have our on general health. Free radicals in living cells Free radicals are present in all living cell and are a part of the cell processes. However excessive free radicals in our cells can attack the cell membranes (the outer coat of the cell). This attack causes cell and tissue damage. Radicals can also break strands of DNA (the genetic material in the cell). Some of the chemicals known to cause cancer, do so by forming free radicals.

Antioxidants and health benefits There may be health benefits from the use of antioxidants. Oxidation reactions in the body could be linked to the build-up of fatty deposits that cause blockages in arteries that can cause heart attacks. Antioxidants may be important in preventing this and there could also be a link with the prevention of certain cancers, arthritis and other conditions. The picture is not yet clear and a great deal of research needs to be undertaken.

Do antioxidants help us live longer? Studies involving 230,000 men and women across the UK have shown that there is no convincing proof that antioxidants have any effect on how long people can live. However 40% of women and 30% of men are reportedly taking these supplements and spending over £333 million on them per year.

Researching Chemistry – your first task Your first task is to research the Underlying Chemistry of antioxidants. - you must keep a record of all your notes and of all sources you use. (2 sources required) You must use appropriate sources for Higher Chemistry level. Can you think of any? Higher Chemistry textbooks Scholar website Education Scotland website (google: Education scotland Chemistry) Google ‘SSERC antioxidants’ You must provide ISBN numbers for books and full urls for websites Google ‘BBC antioxidants’ (for more general knowledge)

Researching Chemistry – your first task Your first task is to research the Underlying Chemistry of antioxidants. - you must keep a record of all your notes and of all sources you use. (2 sources required) What do you think might be appropriate content for the underlying Chemistry of antioxidants? Antioxidants are free radical scavengers What is a free radical and how are they formed? (what causes free radicals?) What damage can free radicals do? – to humans and food. Explanation of free radical chain reactions How antioxidants can stop them Examples of antioxidants

Researching Chemistry – your first task Your first task is to research the Underlying Chemistry of antioxidants. - you must keep a record of all your notes and of all sources you use. (2 sources required) What do you think might be appropriate content for the underlying Chemistry of antioxidants? Do not copy text from textbooks or websites – that is called plagiarism and I will be looking out for it. Make notes explaining concepts in your own words please.

Researching Chemistry - Antioxidants Researching Chemistry consists of two assessment activities (assessed by your teacher): This will help you greatly when it comes to writing your assignment later (assessed by SQA). ASSESSMENT ACTIVITY 1- Literature research, including: More focused research surrounding the aim of your investigation. (2 sources required) Finding out about the Underlying Chemistry of antioxidants - you must keep a record of all your notes and of all sources you use. (2 sources required)

Researching Chemistry – your first task Your first task is to research the Underlying Chemistry of antioxidants. - you must keep a record of all your notes and of all sources you use. (a minimum of 2 sources is required) Appropriate content for the underlying Chemistry of antioxidants: Antioxidants are free radical scavengers What is a free radical and how are they formed? (what causes free radicals?) What damage can free radicals do? – to humans and food. Explanation of free radical chain reactions (examples in food) How antioxidants can stop them Examples of antioxidants and their structures

Researching Chemistry – your second task Your second task is to undertake more focused research surrounding the aim of your investigation – again, you must keep a record of all your notes and of all sources you use (a minimum of 2 sources for this section is required) I will be coming round and assessing your work by reading your research notes and asking you questions – i.e. How much of what you have written do you understand and can explain to me?

Researching Chemistry -practical investigation/focused research Your practical investigation will be one the following: 1.Which fruit juice contains the most antioxidants? Or 2. Which tea contains the most antioxidants? The class will be split into 4 groups: 2 groups researching teas and 2 groups researching fruit juices.

Researching Chemistry - possible focus questions A1. Explain why the human body requires antioxidants. A2. Many foods and drinks which contain antioxidants are known as ‘superfoods’. What requirements must be met for a food to be labelled as a ‘superfood’? A3. What evidence is there to suggest that eating ‘superfoods’ is good for human health? A4. Many people make fruit smoothies to get their daily allowance of vitamins from fruits. It is thought that smoothies can be harmful to health. What evidence is there to support this? 1.Which fruit juice contains the most antioxidants?

Researching Chemistry - possible focus questions B1. Is there any evidence to suggest that drinking tea leads to better health? B2. Why do different types of tea contain different concentrations of antioxidants? B6. Green tea is recognised to be very beneficial to health. Describe the health benefits of drinking green tea. 2. Which tea contains the most antioxidants?

Researching Chemistry – a clear statement describing your research topic Once you have completed all your research for the underlying Chemistry of antioxidants and your more focused research surrounding the aim of your investigation, you now need to write a clear statement describing your research topic. i.e. a concise summary of both sets of literature research. This should only be one or two paragraphs and can include diagrams.

Researching Chemistry – a clear statement describing your research topic One or two paragraphs – must be clear and concise! What you could include: -What is a free radical? How are they formed? -What damage can they do? (to humans/food) -What are antioxidants/how do they work? -Examples of foods or teas high in antioxidants -Possibly a structure of an antioxidant -Possible health benefits of antioxidants (something about your focus question) -What is the aim of your investigation? -Name of the experiment you will be carrying out (Briggs-Rauscher experiment)

Researching Chemistry -practical investigation Your practical investigation will be one the following: 1.Which fruit juice contains the most antioxidants? Or 2. Which tea contains the most antioxidants? Our class will be split into 4 groups: 2 groups researching teas and 2 groups researching fruit juices.

A plan of the practical investigation (including a clear aim, hypothesis, variables, method and risk assessment) A record of observations/measurements including labels and units (i.e. ALL raw data). The candidate should be observed to follow procedures safely. A full investigation write-up, including presenting findings in an appropriate format. Researching Chemistry - Antioxidants The raw data from Researching Chemistry will be used as data source 1 in your assignment. ASSESSMENT ACTIVITY 2- Practical research, including:

AIM HYPOTHESIS VARIABLES (Independent, dependent and variables to remain constant) PLAN for your METHOD – you can either photocopy the method from SSERC or write in the full URL. RISK ASSESSMENT – you need the quantities and the composition of the solutions you will be using. you need to check hazard symbols and come up with appropriate safety precautions. RESULTS - A record of observations/measurements including labels and SI units (i.e. ALL raw data). You should be observed by me to follow procedures safely. Once completed your experiments, you should write a full investigation write-up, including presenting findings in an appropriate format (same as a task 1). Researching Chemistry - Antioxidants

Briggs-Rauscher Reaction 2 Reaction 1 Briggs-Rauscher Reactions

Briggs-Rauscher Reaction Watch the demo of the reaction you are going to carry out – you may takes notes if you want, although the detailed instructions are in the SSERC Antioxidants Student’s Guide. Think about variables!

Risk Assessment For your risk assessment, you must: 1.State the name of the chemical, 2.The quantity you are going to use, 3.The safety precaution(s) you are going to take.

Risk Assessment Solution A: 50 cm M potassium iodate and 0.07 M sulphuric acid. Solution B: 50 cm M malonic acid and 0.2 M manganese sulphate. Solution C: 50 cm 3 4 M hydrogen peroxide. Teas or fruit juices. Skin irritant Corrosive Hazardous to aquatic environment Health Hazard Check for possible food allergies

Safety precautions Harmful irritant Corrosive Wear goggles. Clean up any spills. Wash any spills off skin immediately with plenty water. Wear goggles and gloves. Clean up any spills. Wash any spills off skin immediately with plenty water.

Safety precautions Health hazard Hazardous to the aquatic environment Do not put down the sink. Put into a waste bottle for the technician to dispose of. Do not inhale or ingest.

AIM HYPOTHESIS VARIABLES (Independent, dependent and variables to remain constant) PLAN for your METHOD – you can either photocopy the method from SSERC or write in the full URL. RISK ASSESSMENT – you need the quantities and the composition of the solutions you will be using. you need to check hazard symbols and come up with appropriate safety precautions. RESULTS - A record of observations/measurements including labels and SI units (i.e. ALL raw data). You should be observed by me to follow procedures safely. Once completed your experiments, you should write a full investigation write-up, including presenting findings in an appropriate format (same as a task 1). Researching Chemistry - PLAN