The Protein Problem - Part 2
The Protein Problem 2
One of the great challenges facing the food industry over the next few years involves creating a smooth transition from animal protein to plant protein consumption. We must, as I find myself repeatedly banging on about these days, eat more plants and fewer animals if we want a sustainable food future.
I would much rather we all did this by eating legumes, pulses and beans, but I am also a food system realist. I know that most people don’t like Dahls, Chickpea Curries and Black Bean Stews as much as I do, and as Mrs Angry Chef often tells me, they can have some unwanted side effects (she has long commented that I sometimes smell as if I am rotting from the inside). Unlike most UK chefs and food writers, I fully understand the desire to make convenient meat-like burgers and sausages from vegetables, and I am frequently involved in this sort of work as a chef consultant (available now at super reasonable rates - contact through the website).
The reason this currently provides me with gainful employment, is because it is a difficult thing to achieve. Globular plant storage proteins are not very similar to animal muscle fibres, so soya and pea proteins take a bit of coaxing if you want them to resemble flesh. That coaxing requires a few chef skills and a bit of science knowledge, which is fortunate for my ability to pay the mortgage.
In my last book (Ending Hunger, available now), I detailed how most of the plant-based burgers and sausages currently on the market are manufactured. TL;DR (and far too many of you DRed my last book) they are generally a combination of textured plant proteins, fats, seasonings, flavourings and binding ingredients. One thing I did not cover in the book was how the textured protein ingredients are made, so I thought it might be interesting to talk about that here. Because understanding the proteins used in the current range of plant-based products is vitally important when considering the future of our food system.
To make plant-based meat, plant proteins, usually soya, pea or wheat, are extracted and concentrated into something resembling flour, but with a protein content of about 60-90%. This protein is then mixed with water and fed into an extruder, which is basically a long metal tube with a screw thread running though it and some holes at the end. Similar extruders are used to make pasta, starch-based snacks, dried pet food and most breakfast cereals.
The key to successful protein extrusion is to add enough heat and energy into the system to unravel the proteins, and then persuade them to form new structures. As the proteins push along the extruder they uncoil and run along against each other, forming links to adjacent protein strands as they cool further down the pipe. The long, fibrous protein structures formed are reminiscent of muscle fibres, so giving plant-based products a meat like structure.
Soya is very good at this, with proteins that are particularly keen to unravel. Wheat protein is pretty decent too, and can form some really good meat-like structures. But both of these have allergen or digestibility issues, so recently, the hunt for alternatives has gathered pace. Pea is okay, but it is much harder work to make its proteins unravel, so extruded pea protein tends to be a bit softer in structure. Other proteins such as oat, fava bean or chickpea provide even more of a challenge, although by altering the heat, pressure and speed in clever ways, you can usually make something edible. There is a lot of ongoing work looking at how to make some of these more difficult proteins better at unravelling, with enzyme modification being a potentially useful strategy (if any science folk who read this blog have bright ideas about how to do this, please let me know).
Although the extruder used is broadly similar, there are two main types of plant protein produced in this way, High Moisture Extruded Protein and Low Moisture Extruded Protein. The low moisture version produces a dried product, similar to the sort of textured vegetable protein you have been able to buy from health food shops for decades. It makes passable sausages, burgers and Bolognese, and is the type of ingredient most used in the industry today.
High moisture extrusion, something that has only become popular over the past 6 years or so, involves adding more water into the extruder pipe, being a bit more careful about controlling the heat, and cooling it down more in the later stages, resulting in long fibrous structures. These plop out the machine in a high moisture block, producing a continuous stream of plant ‘meat’. As this results in a wet product that must then be cooled and chilled, it is a more expensive process, usually reserved for premium products. Most famously, Beyond Meat use a high moisture extruded pea protein for their (incredibly expensive) burgers and sausages.
Within the industry, it is currently thought that High Moisture Extrusion produces more realistic meat replicas, although by tweaking the process a little, it is possible to produce good quality dried ingredients with equally long protein fibres. It may be that, even among manufacturing professionals, dried TVP has cheap associations, evoking crappy 1980s vegan health products, and the high moisture process is preferred for this reason. I have no particular skin in the extruded protein game, although I do feel that this is a shame. Low moisture products are better value for end consumers and have significant environmental benefits.
It seems likely to me that consumers care little about the type of extrusion technology and are more interested in how the end product tastes, so I wish there was more industry focus on improving the quality of dried textured protein. Although to counter this opinion, Beyond Meat has a current stock market valuation of $7 billion, largely based on its use of High Moisture Extrusion, so what do I know.
Like it or not, finding ways to create delicious, palatable plant proteins is the future of food. People talk about insect farms, biomass fermentation and cellular agriculture because they are shiny new technologies, but as we move away from our dependence on animal agriculture, it will be crops such as soya, wheat, fava and pea that meet most of our protein needs.
Until now, we have used livestock to convert these crops into delicious food products, feeding beans and grains to animals, who unwittingly transform the plant proteins into tasty, edible eggs, milk or flesh. This has long been a bizarre, cruel and horribly inefficient way to feed the world. The use of protein extrusion to create analogues of flesh might not feel natural right now, but it is a future we need to come to terms with. Extruders are far more efficient than a pig, use less land than a cow, and are cheaper to maintain than chickens.
Right now, even the greatest advocates of extruded plant protein would struggle to claim it tastes as good as meat. But there are hundreds of chefs and technologists like me working hard to improve this. Things are moving in the right direction, and one day might compare. In many ways, the future of food depends on it.