This page is the landing page for a series of food chemistry experiments which were devised to support some videos produced by Abertay University, the Scottish Food and Drink Federation, Education Scotland and SSERC.
The experiments can all be carried out easily in the classroom and help to illustrate the importance of chemistry and chemists to the food industry – a hugely important part of the Scottish economy.
The Experiments (which can be accessed along with the videos by clicking on the links below) are:
Emulsions – A look at emulsion formation and the effect of different emulsifying agents.
Enzymic browning – A look at the conditions that affect the rate of browning of apples (as an exampke of fruit and vegetables in general)
Maillard Reactions – some simple examples of this hugely importanc class of reactions between sugars and amino acids that produce colour and aromas in many cooked foods.
Oxidative Rancidity – Simple experiments to investigate the effect of different conditions on the oxidation of fats.
TLC of amino acids in Soy Sauce – an investigation into the different amino acids that can be found in different types/brands of soy sauce.
As well as videos to support each of the activities, there is another one that showcases the different employment opportunities, particularly for scientists, in the food industry.
If ypur interenet does not allow easy watching of this online, you can download it here. Right-click on the link and select ‘save link as . . .’ or ‘save target as . . .’
An emulsion is a particular subgroup of colloids: a mixture of two fluids such as oil and water. The mixing to form the emulsion is achieved by breaking up the molecules in both substances into very fine, small droplets in order to keep the combination from separating.
There are several common foods that are classed as emulsions: milk, margarine, ice cream, mayonnaise, salad dressings, sausages, and sauces like béarnaise and hollandaise. When packaged and manufactured on a larger scale, most of these foods need emulsifiers to stabilise the mixture and keep the different ingredients from becoming separated.
This investigation looks at emulsion formation and stability and at the effect of different emulsifying agents.
Emulsions – Teacher/Technician Guide
The short video about emulsions which you can watch below, can be downloaded here if your internet connection does not allow online viewing.
It is indisputable that fruit and vegetables are good for us. It is also unarguable that unappetising, brown-looking fruit and vegetables are not likely to be eaten.
Theis browning is caused (mainly) by enzyme activity and it is in the interest of the producers as well as the customers to find ways of slowing the process to ensure that our fruit and vegetables remain looking tasty for as long as possible.
This investigation looks at enzymatic browning in cooking apples (as they go brown faster than just about anything else) and at some of the factors that can affect the rate of the process.
Enzymatic Browning – Pupil Guide
Enzymatic Browning – Teacher/Technician Guide
Enzymatic Browning – Risk Assessment
The short video about emulsions which you can watch below, can be downloaded here if your internet connection does not allow online viewing.
Maillard reactions involve some extremely complex chemistry but at heart they involve reactions between sugars and amino acids.
These produce a wide range of compounds that contribute to colour and aroma.
Maillard reactions are responsible for the colour and aromas of roasted meat, or toast, fried onions, the colour of coffee and tea and also for the production of many artificial flavourings.
This investigation looks at some simple maillard reactions and allows the pupils to see the colour changes and the aromas that are produced as the reaction proceeds.
Maillard Reactions – Pupil Guide
Maillard Reaction – Teacher/Technician guide
Maillard Reactions – Risk Assessment
The short video about emulsions which you can watch below, can be downloaded here if your internet connection does not allow online viewing.
We are all familiar with the unpleasant experience of eating peanuts or crisps that are too old, or with the smell and taste of rancid butter. This is due to oxidation of the fats and oils in these foods and it affects all types of food that contain them: meat, fish, nuts etc.
Because of their chemical structure, unsaturated fats and oils are subject to oxidative breakdown, so-called oxidative rancidity. This reaction is a free radical chain reaction that involves abstraction of hydrogen from the fatty acid chain followed by a series of reaction with oxygen, rearrangements, and chain cleavage to produce nasty smelling and tasting compounds.
This investigation looks at some of the factors that can affect the rate at which this oxidation occurs – using β-carotene as a proxy marker to visualise the process.
Oxidative Rancidity – Pupil Guide
Oxidative Rancidity – Teacher/Technician Guide
Oxidative Rancidity – Risk Assessment
The short video about emulsions which you can watch below (or on Youtube here) If your internet connection does not allow online viewing click here to download a copy . . . assuming your internet will allow that.
Soy sauce is made from a fermented paste of boiled soybeans, roasted grain, brine, and particular varieties of Aspergillus fungus. After fermentation, the paste is pressed, producing a liquid, which is the soy sauce, and a solid by product, which is often used as animal feed. Soy sauce is a traditional ingredient in East and Southeast Asian cuisines, where it is used in cooking and as a condiment.
Both the fermentation and the acid hydrolysis result in some of the protein being broken down into peptides and further into individual amino acids. The exact composition will vary from product to product; typically being high in Valine, Tryptophan, Lysine, and Histidine.
This investigation uses thin-layer chromatography to compare the amino acid contents of different soy sauces.
TLC of Soy Sauce – Pupil Guide
TLC of Soy Sauce – Teacher/Technician Guide
TLC of Soy Sauce – Risk Assessment
The short video about the TLC of soy sauce which you can watch below, can be downloaded here if your internet connection does not allow online viewing.
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