Researchers have cooked up a recipe that mimics the rich aromas of meat, using an unusual mix of onions fermented with fungi. By fine-tuning the type of fungus and fermentation time, they were even able to produce a specific aroma that is almost indistinguishable from liver sausage, a panel of smell-testers found.
This could be a boon for the meatless meat industry, which has long struggled to replicate meat’s texture, flavor and scent. Meat gets its deliciously savory, smoky, caramelized aroma from a complex chain of reactions that unfold when it is cooked, releasing volatile compounds that are responsible for the mouth-watering odors of frying bacon, or a burger sputtering on the grill.
Food scientists have worked hard to mimic these qualities in plant-based meat alternatives using chemical additives that go some way to replicating the richness of those flavors. But there’s a catch: these additives mean the food products that contain them can’t be classed as ‘natural’, according to the law in places like Europe.
To get around this, the researchers on the new study went on a hunt for natural flavors, settling on Basidiomycetes as their starting point: this diverse group of fungi is known to generate meaty aromas when fermented with different types of food. The question was whether this flavor profile could be honed into something indistinguishable from meat.
To find out, the researchers picked a variety of spices to trial the fungi with: red bell peppers, chives, wild garlic, onions, ginger, mustard seeds, and leeks. These were individually mixed in a concoction of water and with different fungi, and then left to ferment for hours. Then, a panel of professional testers were asked to give the resulting broths an expert sniff.
While ferments made with peppers, ginger, and mustard seeds didn’t produce any meaty flavors, the other pairings more than made up for this, with the panel of testers detecting a pleasant aroma—likened to the savory scent profile of instant soup—from the broths made with onions, garlic, leeks and chives.
All in all, the researchers developed 13 fungi-food combinations that produced meaty scents. But of these, by far the meatiest combination came from onions mixed with a type of fungi called Polyporus umbellatus, which when fermented together for at least 18 hours, produced an intense, complex aroma that the testers likened to liver sausages.
The researchers also used gas chromatography-mass spectrometry to analyze the oniony broth, and found that several of the emitted chemicals were the same as those that produce the favorable flavors in meat. They think this is owing to onions’ high sulfur content, which is also present in the compounds that give meat its unique aromas.
Meanwhile, this study isn’t the only recent fermentation win for plant-based foods. In separate research published this month, a team of scientists managed to ferment pea proteins with cheese bacteria, finding a blend that produces the same firm, gel-like consistency, and some of the aromas, of real dairy cheese. That team of scientists thinks it could be an alternative to the array of starches, fats, gelling agents, and flavorings that are required to give vegan cheese its taste and consistency.
Both these inventions are far from product-ready. But they lay down a path for natural enhancements of plant-based alternatives, which have come under rising scrutiny in recent months due to the potentially harmful additives they contain. After the initial boom of plant-based foods, many of these companies are now also struggling to grow their consumer base—but the promise of all-natural, lusciously-flavored alternatives might be the boost they need.
Zhang et. al. “Generation of Meaty Aroma from Onion (Allium cepa L.) with Polyporus umbellatus: Fermentation System, Sensory Profile, and Aroma Characterization.” Journal of Agricultural and Food Chemistry. 2023.
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