I just want meat that tastes like real meat…
Most people know that the future of the planet is in our hands. Current western lifestyles are unsustainable and incompatible with minimising global warming. Without a drastic change in our excessive habits, keeping average global temperature rise below two degrees will be close to impossible.
One of the main causes of carbon emissions is our carnivorous inclinations: agriculture currently makes up 30 percent of all greenhouse gas emissions, mainly from livestock and grain grown to feed livestock. As the global population approaches 8 billion people, and millions of people are lifted out of poverty, global meat consumption shows no signs of slowing down.
Now, many companies and researchers are experimenting with alternative ways of satiating our desire for meat that don’t involve slaughtering animals or using the planet’s precious resources. They are going beyond traditional meat substitutes such as vegetarian ‘sausages’ and tofu, and trying to replicate the taste and texture of meat as closely as possible.
Broadly, their methods fall into two categories: those using animal cells to grow meat in a laboratory, and those which are plant-based and use genetic engineering methods to emulate the meaty taste. I’m going to examine the science behind both of them, to see if either is likely to be commonplace on the dinner table in the near future.
The reason cooked meat has so much flavour compared to raw meat, which is virtually tasteless, is a series of chemical reactions known as Maillard reactions. In these reactions, heat (typically above 140C) causes reactions between sugar and amino acids in proteins.
In the simple initial reactions, the carbonyl in the sugar and the amino group of the amino acids react to form new molecules. The formed molecules are flavour compounds, and they continue reacting and breaking down, generating many hundreds of different, complex molecules. These combination of the compounds is responsible for the taste of cooked meat.
Maillard reactions take place in most other foods cooked at high temperatures, including roasted vegetables and baked cakes, but the particular combination of amino acids and simple sugars in meat gives it a distinct flavour. Part of the challenge of creating fake ‘meat’ is replicating this combination.
The Impossible Burger
The Impossible Burger aims to recreate the experience of eating a burger only using plant material and a genetically modified yeast. They believe that heme, a compound found in meat, is mostly responsible for the taste and colour. Found in the blood in haemoglobin and in the muscles in myoblobin, it is also present in leghemoglobin, which is found in soy plants.
Unfortunately, the quantities of heme in soy plants are insufficient to recreate the meaty taste. But by genetically modifying yeast organisms, it can be grown it in substantial quantities. The modification involves extracting the genes responsible for leghemoglobin in soy and inserting them into yeast. The yeast is fed, and as it grows it produces heme which is harvested. The environmental impact of yeast is minimal compared to growing an entire field of soy.
To recreate the texture of a beef burger, they have found and modified a range of plant proteins, including from wheat and potato. The wheat protein makes the burger chewy, while the potato helps to hold water. They use coconut oil for fat, but have isolated and removed the coconut flavour so it is a neutral addition to the burger.
Through their experimentation, they have created a burger which they claim is virtually indistinguishable from a traditional beef burger. Their methods emphasise that the flavours and textures we experience when we eat are just a result of physical and chemical properties of the molecules which make up the food. But does knowing that it is made from plants mean that it will never be quite as satisfying?
Petri Dish Meats
The other method of recreating meat involves growing it in the lab using cells extracted from live animals. Whether this is real or fake meat is debatable, as although no animals were harmed in the process, the ‘meat’ still consists of animal cells.
To make a steak, stem cells are extracted from a cow’s muscle. These are grown in the lab until there are sufficient quantities to harvest, which takes about a month. The newly grown muscle cells are bound together and combined with fat cells, which contribute to much of the moisture and distinctive taste of meat.
How the cells are fed is an issue of contention, as currently they are fed with a serum which contains the blood of calf foetuses. This means that they are still very much animal products, but it is hoped that this serum could be devoid of animal products eventually.
Lab grown meat is undeniably better for the planet, using 99 percent less land, 90 percent less water and producing fewer greenhouse gases than the equivalent amount of livestock.
To grow meat on a large scale will require massive bioreactors, but this is not an insurmountable challenge, as similar technologies are used currently to brew beer.
A meat-free future?
Laboratory meat is still very much a work in progress, but the scientists behind it expect that it could become a reality within our lifetime. Plant based substitutes are already on the shelves, and their likeness to real meat is rapidly improving.
As with much of science, one of the main barriers to commercialisation of either of the methods is the regulatory process. Genetically modified organisms must be approved by relevant government authorities, and it is still unknown whether lab grown meat is likely to be approved.
Of course, the ultimate barrier is whether people will eat the ‘meat’. Many people are wary about eating food grown in a lab, and perhaps part of the satisfaction of eating meat comes from knowing that it once was a live animal. Is growing meat a little too much like playing God? Whatever the moral and ethical issues, the scientific quest continues.
- The problem with fake meat: https://www.technologyreview.com/s/536296/the-problem-with-fake-meat/
- What about eating insects instead? https://theconversation.com/bug-burgers-anyone-why-were-opening-the-uks-first-insect-restaurant-49078
- Will eating faking meat make a difference?(Study) http://www.sciencedirect.com/science/article/pii/S2211912417300056