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Feature

Molecular Gastronomy – Food colours and engineered fare


As we have seen, Molecular Gastronomy is a new innovative field researching the science behind food and cooking. From perfecting the ultimate recipe to understanding how our taste buds work, it encompasses many different areas of science. So there’s something for everyone. We have seen how the field was started and by whom, what it can teach us about our eating behaviour. We have debunked some cooking myths and described how we taste and the implications on our cooking habits. In the final section of this piece, a more biochemical view point shall be taken.

Myoglobin heme ring

Ever wondered what makes food change colour when it is cooked? Why the texture can be so different? It all comes down to basic chemistry. Everything around us is made up of atoms, combined into specific shapes – molecules. All molecules code for different things and the shape of a molecule can code for the colour or texture of the body storing it. The atoms in molecules are held together by bonds. These bonds can be disrupted many different ways, inside or outside the body, ultimately leading to the molecule changing shape or loosing some of its atoms. It will then code for something different, or in our case a different colour or texture. Let’s clarify with some example. Raw red meat is, by definition, red. Meat is mainly composed of muscle cells which contains myoglobin, a protein which can bind to iron and oxygen. Combined with oxygen, myoglobin forms a molecule called oxymyoglobin which is red. The interesting component of myoglobin is the heme ring on its surface. As meat is cooked, the heme ring in myoglobin changes shape. An iron molecule becomes oxidated, leading to the formation of metmyoglobin, which is brown. Think of it as iron rusting after a prolonged exposure to oxygen.

Eggs are a noteworthy double example. When cooked not only do they change colour (the egg white in fact turns white) but its consistency transforms from a liquid to a solid. The change in texture in due to the proteins contained in the egg white. Proteins are made up of long chains of amino acids. In their raw form, these chains are folded into specific shapes, with a certain number of interactions and bonds. When an egg is cooked, a process called denaturation occurs – the bonds holding the proteins together break. The amino acids of a protein are now free not only to bond with each other with also with the amino acids of other proteins. It is this increase in bonds which causes the texture to change from fluid to firm. This same process is responsible for the colour change. When the proteins all bind together, they form a tight weave. In this structure, they are capable of deflecting rays of light that would normally pass through the slack net of a raw egg white.

A controversial topic encompassing food and science is GM (Genetically Modified) foods. Whether you are for or against, it seems there is insufficient data to prove whether they are a danger to our eco-system or a solution to world hunger. So what is all the fuss about?

GM foods are foods that have had their DNA tampered with by genetic engineering techniques to allow them to grow more efficiently. Transgenic plants have been the main focus of this work. The inspiration is to create plants which are resistant to the bugs, viruses or pesticides which lead to crop failure. There is also the idea of increasing these plants’s content in vitamins and such to provide better nutrition.

Here’s a for instance (from my Molecular Genetics course in 3rd year!). Plants are often attacked by insects, which depletes the crop substantially. It is possible to engineer plants which contain a biopesticide – often a bacterium which would kill the insect eating the plant. After a while, the insects stop trying to eat the plant. A bacterium called Bacillus thuringiensis (or Bt) can be used to attach the insects. It produces a protein (in the form of a protoxin) which can attach itself to the cell lining of an insect’s stomach, creating holes in it which leads to the insect’s death. Obviously it’s not quite this simple, genetic engineering is very complex and there is always the issue of the insect builing up resistance to the bacterium but thats’s the main idea.

Bt toxic mechanism of action

This year saw the creation of the first synthetic life-form. A bacterium that lives in the intestine’s of goats and cows, Mycoplasma mycoides was successfully copied and Mycoplasma mycoides JCVI-syn1.0 was born. After sequencing the whole genome of this organism, the feat of molecular genetics was achieved by creating over 100 cassettes composed of 5,000-7,000 base pairs of nucleotides (the founding parts of DNA – see my article on the genetic code) and assembling them to create the 580,000 long sequence of the Mycoplasma mycoides genome. This discovery has also been the subject of controversy. With a media craze denouncing the researchers as “playing God”, the understanding of the science behind the discovery and its purposes is minute. But what has this got to do with food and molecular gastronomy? One of the notions born of this research is that scientist will start to produce synthetic foods. While this might sound scary, it can also be hopeful. Here might be another way of resolving world hunger. It could also mean bridging the gap between meat eaters and vegetarians; if meat could be created without the killing of live animals. Although the idea and theoretical knowledge to do so is there, we are far from achieving this kind of futuristic science. It is also very important to understand the technology used, what the risks are and perform extensive research in the field. This goes for both the scientist getting too excited about his newfound discovery and the media which often fails to properly explain things to the public. And as far as ethics are concerned, we can be sure that, like with GM foods, ethics procedures as well as risk assessments will be top of the list of priorities.

Mycoplasma mycoides JCVI-sync1.0

And some we come to the end of your gastronomic journey. What have we learnt? With the help of molecular gastronomy, we can better understand what we eat, how we taste it, how we cook it, why we like it and how we can engineer it. From fun facts demystifying old wives tales to hard molecular genetics through information to make us all better cooks, this new field is definitely one to watch!

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About me

Natacha is a research scientist and a lover of all things science! She love finding out interesting facts about all aspects of life, whether it’s how genetic engineering works or what the difference between crimped and straight hair is. There’s a bit of science behind every mystery and the Science Informant will help find the clues for everyone to enjoy and understand the amazing world of science!

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