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Precision-Fermented Sweeteners

Jan. 11, 2024
Modern technology added to an age-old process is increasing options and lowering prices of non-nutritive sweeteners.

Sugar is a tough ingredient to replace. Every artificial sweetener approved by the FDA, ranging from saccharine to aspartame and from sucralose to stevia extract, imparts sweetness. But none quite matches the other characteristics of sugar, such as mouthfeel, bulk and moisture retention, and many add an “off” taste.

The latest category of artificial sweeteners – precision-fermented sweeteners – appears to be closer than any previous sugar replacement in matching these other characteristics.

“There has been a sweetener evolution for sugar reduction in recent years, which has motivated brands to move away from artificial sweeteners and invest in unique sweeteners and flavor enhancers,” says Casey McCormick, vice president of innovation for Sweegen ( The company launched its Sweetensify Collection for taste modulation, including precision-fermented brazzein sweetener, in April 2023.

“Advancements in ingredient technologies have enabled manufacturers to more accurately reproduce various sensory and functional aspects of sugar, such as sweetness, mouthfeel, bulk, browning, and moisture retention, all while reducing the sugar and calorie content,” he says.

What is precision fermentation?

Ingredient companies discovered long ago that some plants created sweet-tasting molecules other than the simple carbohydrates of sucrose, fructose or glucose, otherwise known as sugar.

Stevia rebaudiana, a green leafy plant found in Paraguay and Brazil, for example, creates compounds called steviol glycosides, which are 50 to 300 times sweeter than sugar but have no calories. Rebaudiosides A and M, or reb-A and reb-M, are popular steviol glycosides.

Reb-A and reb-M are effective sweeteners and match many of the characteristics of sucrose. They are calorie-free because the human body does not absorb them. Reb-A is more plentiful than reb-M – it accounts for 2-4% of the dry matter of stevia leaves, compared to less than 1% for reb-M -- and it can be extracted from the stevia plant affordably enough to create commercial quantities. Truvia, PureVia and SweetLeaf are reb-A sweeteners made with extracted reb-A.

But reb-M, which is substantially sweeter than reb-A, appears naturally in such low quantities that extraction doesn’t make financial sense.

A similar situation exists with brazzein, a protein found in the fruit of the oubli plant, which grows in the African countries of Gabon and Cameroon. It’s also super sweet and calorie-free, and compares well with sugar in the right circumstances and recipes. It is stable over a pH range from 2.5-8 and is heat stable at 80 C for four hours. But extracting enough brazzein from oubli plants to make it commercially viable is not feasible.

Enter precision fermentation. Fermentation is the chemical breakdown of a substance by bacteria, yeasts or other microorganisms, which can result in the production of a desired product, such as alcohol. “Precision fermentation” is fermentation in which those microorganisms are genetically modified to produce the desired product.

Precision fermentation is used to create a variety of proteins on the market, such as egg whites from The Every Company ( (formerly Clara Foods) and dairy proteins from Perfect Day Inc. (

Precision fermentation also is used to create sweeteners. Amyris (, for example, uses precision fermentation to make the reb-M sweetener Realsweet. Reb-M is created by a bio-engineered yeast that ferments sugarcane. The reb-M created by precision fermentation has exactly the same chemical structure as naturally occurring reb-M found in the stevia leaves.

Precision fermentation also is the source of the brazzein used by Oobli ( in its line of sweet teas and chocolates.

“Making sweet proteins like brazzein at Oobli is a lot like brewing beer,” says Jason Ryder, founder and chief technology officer of Oobli. “We start with a food-grade yeast, and we teach it to ‘brew’ the sweet proteins originally found in plants through fermentation. Once we make our sweet protein brew, we remove the yeast and water, leaving only sweet proteins. In its dry powder form, brazzein looks and tastes a lot like sugar - it's just a lot sweeter, so you need a lot less in each serving.”

How to replace sugar?

Reb-M is known for a clean, quick sweetness. It lacks the bitterness associated with stevia glycosides produced by extraction, such as reb-A, because the fermentation process does not create the impurities that cause the bitterness in reb-A.

Reb-M is rarely a 100% replacement for sugar, though in some products that is possible.

Similiarly, brazzein is not exactly an analogue of sugar. Ryder says sweet proteins like brazzein momentarily bind with the sweet taste receptors on a person’s tongue to create the sweet sensation, but they don’t “bombard” those receptors the way sugar does.

And as with reb-M, in some cases, brazzein can replace the sugar in processed food, but more often it allows for the reduction of sugar. For example, Oobli’s sweet teas contain 75% less sugar than an equivalent, fully sugar-sweetened tea, Ryder says.

“Every food and beverage formulation and how it uses sugar is quite different,” he says. “But, assuming we want to match the sweetness of the product that we replace, we can typically reduce sugar with brazzein in most products by 60-75% with no change to taste.”

Brazzein can be used in a complementary fashion with other non-sugar sweeteners, notes McCormick of Sweegen, which attained FEMA Generally Accepted as Safe (GRAS) status for brazzein earlier this year. Sweegen’s brazzein can be used in conjunction with stevia to create the flavor profile a food processor needs.

“Unlike ordinary sweeteners, brazzein hits the T1R3 receptor on the tongue, which is linked to the perception of sweetness and umami,” McCormick says. “This unique property enables a higher quality of sweetness that amplifies flavor expression. The result is a more sugar-true taste experience.”

Brazzein’s ability to intensify umami as well as sweetness is key to its value to food processors, McCormick adds. The company’s sensory tests have shown that brazzein can reduce bitterness in products such as coffee and maintain sweetness and other characteristic flavors in energy drinks and cocktails.

 “When used as an ingredient in foods and beverages, brazzein not only impacts sweet quality, but it also enhances other characteristic flavors – offering tremendous flavoring qualities beyond sweetness,” McCormick says. “It is heat-stable, pH-stable, and exhibits excellent shelf life.”

Sustainability benefits

 A side benefit of sweeteners made by precision fermentation is they require far less natural resources than sugar or other naturally produced sweeteners. Because the desired sweeteners are produced in fermentation facilities rather than extracted from plants, the water, energy and land usage is less.

Ingredion, which has a portfolio of stevia products that includes reb-M from fermentation, conducted a global study in 2022 to better understand the sustainability of stevia across its product life cycle compared to cane sugar, beet sugar and high fructose corn syrup. A key finding was that reb-M produced by fermenting sugarcane reduces negative climate change impact by 82% compared to sugar.

“Our latest findings clearly show that all of our stevia production methods consistently outperform sugar across four key sustainability metrics due to recent innovations in reb-M stevia production,” said Kurt Callaghan, global strategic director for sugar reduction at Ingredion, in a press release.

“Reb-M has enabled mass market adoption of stevia... Our bioconversion and fermentation capabilities will allow the industry to achieve the same great taste at an even more affordable price while dramatically improving the environmental impacts.”

Consumer acceptance

 The bottom line with any sweetener is consumer acceptance. Do people like products sweetened with precision fermented sweeteners? Manufacturers say “yes.”

“Brazzein enables manufacturers to respond to consumer demands for reduced-sugar and healthier alternatives without compromising on taste,” Sweegen’s McCormick states. “Collaboration with Sweegen can help integrate brazzein seamlessly into various formulations, providing a competitive edge in the market.”

Tony Pavel, deputy general counsel, global food law at Perfect Day and executive board member of the Precision Fermentation Alliance (, echoes McCormick’s comment:

“As with most food products, taste is king. And we know consumer demand for sustainable food ingredients continues to grow. As more precision fermentation sweeteners come to market, providing food producers with a wider range of formulation options, we expect that consumers will embrace these sustainable, delicious options.”

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