How to add 'sizzle' to meat
Meat-free steak and sausages seem to be everywhere these days. Perhaps you have tried one.
But did you like it? Was it as good as the real thing? If it left you underwhelmed then it could be down to one missing ingredient - animal fats.
Many firms are betting that finding a good alternative to animal fats will provide a breakthrough when it comes to the flavour of meat-free products.
One person who is evangelical about better fat is Max Jamilly, co-founder of London-based Hoxton Farms.
"All of the taste, the sizzle, the browning, comes from fat," he enthuses.
Hoxton Farms is making animal fat, without the animals.
They start with just a few animal cells that are stored in a vat of liquid nitrogen.
Those cells are revived in an incubator, and cultured for around three weeks in a stirred tank bioreactor, essentially a laboratory mixer.
During that time, the cells are fed with a proprietary mixture of plant ingredients.
Eventually, out of a metal pipe that resembles a large syringe, will emerge a pale yellow, buttery substance: the fat.
Despite the company's name, there's not a farm animal in sight. And the lab is a more hygienic environment than many animal agriculture operations.
Mr Jamilly believes that while the alternative meat world has made great strides with protein, it's being held back by conventional fats.
In meat replacements these have included canola, palm, soy and sunflower oils.
The mainstay has been coconut oil but, compared to animal fat, this has a lower melting point, or the point at which fat turns from solid to liquid.
So during cooking, the oil in some alternative meats can melt away, leaving the end product without the juiciness of a real burger or steak.
If you've mashed your way through a vegan burger that started off juicy, but then turned to sawdust, the melting point may be the culprit.
Mr Jamilly and his fellow co-founder Ed Steele says their fat can counter that problem. As well as having a higher melting point, it can be easily dispersed through the product.
In contrast, some plant-based burgers might be studded with white specks of solid coconut oil that haven't been distributed uniformly.
Compared to some alternative proteins using coconut oil, Mr Steele believes "the difference is that it's juicy, not greasy".
Using coconut and other oils has one advantage though - they are widely available and relatively cheap.
Hoxton Farms thinks it can match traditional oils in the coming years, but it will have to expand.
Last year it raised $22m (£18m) to build a pilot production plant, but it will need to get even bigger.
Mr Steele believes their product can help keep manufacturer costs down, by providing so much flavour that they don't need to rely on additives like flavourings and bindings, in addition to plant oils.
Another alternative is precision fermentation, which ecologist Nicholas Carter believes is a major, underappreciated solution.
Precision fermentation involves engineering microbes to produce the desired material in a fermentation process. In Gothenburg, Sweden, for instance, Melt & Marble is tinkering with yeast cells to generate specific fats. The company is targeting prices below €5-10 per kg.
Mr Carter says that while cultivated fats could still be decades away, precision fermentation has already been commercialised. "With precision fermentation, you can have a lot more ingredient replacements." And with time, he believes, "there's no reason this should not cost the same or less" as conventional fats.
In California, Zero Acre Farms raised $37m in 2022 to produce alternative oil using microbial fermentation. While its oil is currently selling for several times the price of olive oil, Zero Acre Farms argues that making its product uses substantially less land and water than conventional plant oils, and has more culinary applications.
Another vegan-focused twist on an old food technology is emulsion. Friederike Grosse-Holz, who sits on the board of Barcelona-based Cubiq Foods, describes the company's fat alternative GoDrop!:
"The way it works is the plant-based product is an emulsion, so it's a mix of plant oil and water, a bit like a salad dressing. Only this emulsion is stabilised, so it gives you the kind of solid chunky fat type of feeling that you are used to from animal fat."
Ms Grosse-Holz, who is also a scientific director for the sustainable investment firm Blue Horizon, says that one advantage is that "the resulting plant-based sausage is lower in saturated fat, and can be made lower in total fat, than animal products".
More technology of business:
Cubiq Foods, whose investors include controversial food giant Cargill, has aimed for a price comparable to coconut oil.
Overall, plant-based foods consultant Michele Simon is sceptical. Plant-based meats are already often more expensive than animal-based meats, which tend to be artificially cheap due to agricultural subsidies. "There are a lot of alternative facts about alternative fats," she says.
Ms Simon argues that with certain high-tech fat alternatives, "the technology is so far from being commercially viable," and the limited scale will drive up costs.
"Nature has done an amazing job providing healthy fats," says Ms Simon. She notes that taste and texture are much more complex than the fat source.
While fat carries flavour, "the 'meaty' flavour can generally be imparted by using natural flavourings," says Linda Ho, the lead food scientist at the NAIT Centre for Culinary Innovation in Edmonton, Canada.
"There is quite a bit of research being done to replicate, using plant-based ingredients, the umami and savoury flavours experienced when consuming meats."
People like Ms Simon worry that alternative fat start-ups are in an economic bubble. And according to the market research firm Mintel, amidst cost-of-living pressures, Brits are less interested in pricey hyper-realistic meat substitutes, and more interested in inherently vegan foods that don't mimic meat.
However, there is plainly a great deal of market interest in innovative fats for realistic meat replacements. The Hoxton Farms co-founders say they have more interest from potential partners than they can supply. As with many other producers of innovative fats, their main customers are food manufacturers rather than ordinary consumers.
The barrier is how much they can produce, not how much business they can drum up, so Hoxton Farms is on a hiring and building spree.
"I think we're just at the cusp of a lot of things happening," says Mr Jamilly.