Minor Stevia Extracts Like Reb M and Reb D Are in High Demand. How Can Stevia Suppliers Scale Up Supply?

Nutritional OutlookMay 2018 Issue
Volume 21
Issue 4

Minor glycosides like Reb M and Reb D are still in smaller supply compared to a major glycoside like Reb A. How will suppliers increase the supply of these rarer in-demand glycosides?

Photo © Shutterstock.com/govindji

Stevia (Stevia rebaudiana) has made great global strides in just a decade as a zero-calorie food and beverage sweetener. In March, stevia supplier PureCircle (Chicago), together with market researcher Mintel, reported that the worldwide number of foods and beverages launched with stevia grew by more than 10% in 2017 over 2016, with 3500 such products launched in 2017 alone. Overall, they estimated, stevia is now present in more than 16,000 food and beverage products across the globe. Also, as stevia use grows, this plant-based sweetener is taking market share from other high-intensity, low-calorie sweeteners like aspartame, sucralose, and acesulfame potassium. In 2017, Mintel said, stevia was more widely used than aspartame in foods and beverages containing high-intensity sweeteners.

The drive toward stevia is the direct result of growing global concerns about obesity and diabetes prevalence, and a subsequent effort to reduce sugar consumption among consumers young and old. Mintel noted that the number of stevia-containing food and beverages launched specifically for young children grew a whopping 16% between 2016 and 2017.

Whether it’s in beverages, snacks, dairy products, or confectionery, the opportunities for stevia are ripe-and ripening further as suppliers improve the taste of their stevia ingredients.

Some suppliers are now working on producing greater quantities of the stevia leaf’s minor steviol glycosides, like rebaudiosides M and D, which are said to taste more sugar-like compared to the more common steviol glycoside rebaudioside A. (Some Reb A sweeteners are said to have a bitter, or licorice-like, aftertaste.)

Unfortunately, minor glycosides like Reb M and Reb D are still in smaller supply compared to a major glycoside like Reb A. This is chiefly because there is a much smaller quantity of these minor glycosides in the stevia leaf compared to a glycoside like Reb A.

For suppliers, the question right now is how best to increase access to glycosides like Reb M and D. Some believe the answer is still rooted in stevia leaf extraction-namely, gradually breeding stevia leaves that yield higher percentages of the minor glycosides. (As discussed later, some companies are also further enzymatically treating their stevia leaf extracts to improve taste.) This kind of plant breeding takes time, however, and, as one can imagine, significant scale-up of these glycosides within the leaf can take years, often decades, to achieve.

On the other hand, one company, Cargill (Minneapolis), has finally come to market with a stevia ingredient it’s been developing for years-one that does not involve traditional leaf extraction at all. Dubbed EverSweet, this Reb M and Reb D sweetener is produced using fermentation. (Cargill worked with fermentation ingredient specialist Evolva in Reinach, Switzerland, to produce EverSweet.) While EverSweet is not extracted from the stevia leaf, that is exactly the point, the companies would say. EverSweet’s Reb M and Reb D glycosides can be produced through fermentation alone (in fermentation tanks), meaning one does not have to rely on plant breeding, agricultural farming, or on land and water use to make it.

Opinions remain mixed on the best way to scale up production of Reb M and Reb D. For instance, the companies that remain committed to the notion of leaf-based stevia say that adhering to leaf-based extraction, as opposed to fermentation, is key to preserving stevia’s biggest selling point: the fact that it is a natural, zero-calorie plant-based sweetener. (Other major zero-calorie sweeteners like aspartame, sucralose, and acesulfame potassium cannot say the same.)

But, in the face of growing demand for these minor glycosides, is it truly possible, through traditional leaf extraction, to sufficiently increase supply and to do so in a timely manner? Or, will more food and beverage makers seek ingredients like Cargill’s EverSweet that are produced using alternative methods?

Why Reb M and Reb D?

First, let’s review again why minor glycosides like Reb M and Reb D are so darned desirable.

Listen to how ingredient supplier Ingredion (Westchester, IL) describes the Bestevia brand of Reb M and Reb D ingredients it supplies. Bestevia Reb M, launched in 2017, “is 300 times sweetener than sugar and offers a sweet taste experience that is very sugar-like,” says Afrouz Naeini, senior marketing manager, sweetness and beverage, Ingredion. “The clean sweetness, coupled with the lack of bitter aftertaste that is typically associated with stevia sweeteners, enables formulators to replace up to 100% sugar in their product design using a naturally based stevia sweetener.” (Ingredion distributes the Bestevia line on behalf of the ingredients’ developer SweeGen, which is located in Rancho Santa Margarita, CA.)

Bestevia Reb D offers similar benefits, says Kurt Callaghan, marketing manager, global sweetness innovation, Ingredion. “Reb D has a cleaner taste than traditional stevia sweeteners, and sensory mapping shows that Reb D has a sweetness time intensity closer to sucrose than other stevia products,” he says.

Because steviol glycosides like Reb M and Reb D taste more like sugar, formulators can more easily use them to replace a greater amount of sugar-and cut more calories in the process-without negatively impacting product taste. The glycosides’ better taste also reduces the necessity of using taste modulators, points out Katherina Pueller, director, natural sweetener business, SweeGen. “By using Bestevia Reb M and Reb D with that clean, sugar-like taste in their applications, formulators save cost on bitter-maskers,” Pueller says. And because these glycosides are 200-300 times sweeter than sugar, even “small amounts have a huge impact” on sweetening, she says.

Benefits like these are why Reb M and Reb D have come to the fore, say Ingredion and SweeGen. (Last November, the companies jointly announced that Bestevia Reb D received a “no objections” Generally Recognized as Safe (GRAS) response from FDA, clearing its use in U.S. foods and beverages.)

In order to get consumers to permanently switch to lower-sugar foods and beverages, formulators must ensure that these products don’t sacrifice taste. As such, it would not be surprising if companies that are already engaged in formulating with stevia-including CPG giants like The Coca-Cola Co., Kraft Heinz, Nestlé, Groupe Danone, and PepsiCo-increasingly demand greater supplies of better-tasting steviol glycosides.

Starting with the Leaf

Currently, suppliers have different ways of producing Reb M and Reb D. Some suppliers start with stevia leaf extraction and further employ the use of enzymes to refine taste.

Of the Bestevia process, SweeGen’s Pueller says, “Our Reb M and Reb D are produced by a proprietary bioconversion process. Starting with extracts from the stevia leaf, we use enzymes as processing aids to increase the amount of the preferred, best-tasting components. Our bioconversion process is unique and enables us to produce Reb M and Reb D in great quantities.”

In short, she says, “We combine nature, science, and bioengineering to produce sustainable products.”

FDA’s recent “no objections” GRAS letter for Bestevia Reb D describes the process even more specifically: “The process uses a non-pathogenic and non-toxicogenic strain of Pichia pastoris (derived from P. pastoris ATCC 20864) expressing a uridine-5’-diphospho-(UDP) glucosyltransferase that catalyzes the conversion of rebaudioside A to rebaudioside D and a sucrose synthase that catalyzes the conversion of UDP to UDP-glucose.”

PureCircle also uses enzymes to produce some of its stevia ingredients. In a 2016 Nutritional Outlook interview, Faith Son, PureCircle’s vice president of marketing and innovation, described the process the company uses for some of its ingredients this way: “Within our portfolio, we also have leaf-based ingredients that are glycosylated,” she said. “These ingredients start with a traditional stevia leaf extract that’s purified to 95%, and with the use of natural enzymes, add glucose or other sugar molecules to improve taste. We are very transparent about how these products are made and how they differ from our other leaf-based product.”

For this article, she adds, “As the industry-leading innovator and supplier of great-tasting stevia ingredients for the global food and beverage industries, we have a responsibility to understand the various alternative technologies used to produce stevia ingredients. We have specific products we offer which leverage glycosylation, which is processed similar to traditional stevia leaf extracts, as it all begins with the stevia leaf.”

Companies extracting stevia from the leaf say that improving the taste of stevia sweeteners begins with breeding leaves that contain higher amounts of minor glycosides like Reb M and Reb D. Several of the stevia suppliers we interviewed for this article are now focused on 1) breeding leaves with higher contents of Reb M and Reb D, and 2) increasing acreage of these improved leaves.

In February, for instance, PureCircle announced plans to significantly increase its acreage of StarLeaf, PureCircle’s proprietary stevia plant developed through its PureCircle Agronomy Program and its expertise in traditional cross-breeding. The company says StarLeaf “yields roughly 20 times more of the newest and best-tasting stevia leaf sweeteners than conventional stevia varieties.” Son specifies that StarLeaf provides higher concentrations of Reb M and Reb D, along with some other rare glycosides. It also contains Reb A.

A lot of the StarLeaf scale-up is happening in North Carolina, where lands once used to grow tobacco are now being used to grow StarLeaf. Sweet Green Fields (Bellingham, WA) is another stevia supplier who has grown stevia in North Carolina.

Son says PureCircle’s agricultural partnerships are providing economic opportunities to farmers in the area. “We discovered that the skillset for growing tobacco translates extremely well to growing stevia,” she says. “North Carolina also has the soil and climate conditions conducive to growing stevia plants. We are also able to provide North Carolina’s tobacco farmers with new economic opportunities due to the declining demand for tobacco.”

In a press release, PureCircle stated, “Expanding the planting and use of [our] proprietary StarLeaf stevia leaf will enable the company to meet the increasing demand of [the] food and beverage industries for the best-tasting-and most sugar-like-zero-calorie stevia sweeteners.”

Son says PureCircle’s long-term plan is to convert all of its stevia crop to StarLeaf. The conversion process is happening in stages. The company said it plans to plant 16,000 tons of StarLeaf this year and estimated that 80% of the stevia plants it uses this year will be StarLeaf; by next year, it said, this percentage could be as high as 90%.

In a press release announcing the new StarLeaf plantings, James Foxton, PureCircle’s vice president of agriculture operations, said, “We look forward to providing food and beverage companies access to the most sugar-like content from the leaf, at a scale which has never before been possible.”

Other stevia suppliers are also focusing on agronomy improvements to produce more of the minor glycosides. Elaine Yu, president of stevia and monk fruit supplier Layn USA Inc. (Newport Beach, CA), says her company has an innovation center in Shanghai “focused on increasing the yield of exotic steviol glycosides like Reb C and Reb D.”

In February, two companies, natural-sweeteners supplier GLG Life Tech Corp. (GLG; Richmond, BC, Canada) and ingredients firm Archer Daniels Midland (ADM; Decatur, IL), jointly announced the debut of their new Reb M ingredient, which is produced from GLG’s proprietary Dream Sweetener stevia leaf. They said this leaf is “exceptionally high” in Reb M, in addition to containing Reb A and Reb D. Brian Meadows, GLG’s president, says this is the first time the company is supplying a Reb M ingredient.

GLG and ADM take care to point out that this new Reb M product line is physically extracted from the stevia leaf and produced without the use of fermentation or enzymatic processing. A press release from the companies states: “Other competing products in the market use chemical treatments or are produced using fermentation processes that employ non-natural, bioengineered fermentation organisms and enzymes.” The companies say that because their ingredients do not use fermentation or enzymatic processing, they give formulators greater leeway to use them in countries “that otherwise do not permit use of stevia extracts when produced using bioconversion or fermentation methods.” In addition, they say, “Because there are no enzyme enrichment or fermentation techniques employed in the production of GLG’s Reb M product line, they are also clean-label ingredients, an added benefit to formulators looking to meet the growing demand for clean and clear labels…”

Meadows provides a quick overview of the process GLG went through to develop the Dream Sweetener leaf. “GLG developed its high–Reb M Dream Sweetener seedling over the past five years,” he says. The company first publicly announced it had created a high–Reb M seedling back in 2015. That seedling contained 4% Reb M as a percentage of total steviol glycosides. “Historically, stevia seedlings contained less than 1% of Reb M as a percentage of total steviol glycosides,” Meadows says. For comparison, he says, “This high–Reb M seedling was a 1000% increase in Reb M compared to the levels contained in GLG’s Reb A seedlings.”

A year later, in 2016, GLG announced an improved version of the seedling, one that contains 8% Reb M as a percentage of total steviol glycosides. In 2017, GLG began planting this 8%–Reb M seedling, and it now serves as the source of the new Reb M ingredient GLG and ADM are selling commercially.

Meadows says GLG’s goal is to continue increasing the percentage of Reb M in the leaf. “GLG is focusing on developing even higher concentrations of Reb M in the Dream Sweetener leaf and has two agricultural programs focusing on achieving this.” He says the company is also working with “a leading agricultural university” to increase Reb M yields. Last year, the research partnership achieved a “major breakthrough”: seedlings that contain more than 50% Reb M as a percentage of total steviol glycosides, he says. GLG may commercialize this new variety in the future, Meadows says, and also plans to increase the amount of Dream Sweetener leaves it grows.

Breeding Takes Time

Agronomy advancements via traditional plant breeding don’t happen overnight. Dean Francis, CEO of supplier Sweet Green Fields, says his company has been “naturally breeding [its] stevia varieties to improve yields and the taste for over a decade.”

He briefly touches on some of the breeding challenges suppliers can encounter. For instance, he says, “It’s known that a variety that shows a high content of steviol glycosides or strong resistance to diseases in one region may not be able to perform equally well if it is grown in another region.”

Farmers also grow these leaves at the mercy of Mother Nature. In its press release announcing the scale-up of StarLeaf, PureCircle cautioned that, “as with any agricultural crop,” the scale-up of StarLeaf plantings is “subject to various conditions such as weather.”

Enter EverSweet

Cargill says that its EverSweet sweetener sidesteps agricultural challenges because it doesn’t rely on land use and plant breeding to produce. Instead, through fermentation, the company says it can quickly scale up production of Reb M and Reb D.

EverSweet’s development did not happen overnight; on the contrary, Cargill and Evolva have been refining its production process for years. Finally, this March, the companies announced that the ingredient is officially in commercial production.

EverSweet contains the glycosides Reb M and Reb D. Mandy Kennedy, Cargill’s senior marketing manager, describes EverSweet’s advantages: “Only a tiny fraction (less than 1%) of these sweetest steviol glycosides, Reb D and Reb M, are found in the stevia leaf. With such small quantities available in the plant, it would require significant land use and produce too much waste”-meaning, any unused parts of the leaf-“to be commercially or environmentally viable.”

She concludes, “Producing them through fermentation is an inherently more sustainable and cost-efficient way to make the best-tasting steviol glycosides available in sufficient quantities in the mass market.” Fermentation, the firm says, means there is “flexibility to expand [EverSweet’s production] rapidly and cost-effectively.” Cargill says supply is also consistent; by taking place in fermentation tanks, EverSweet’s production isn’t affected by variables that impact traditional agriculture, like poor weather.

Kennedy describes EverSweet’s process thusly: “We feed dextrose (a simple sugar made from corn) to the yeast during the fermentation process. The yeast produces two of the sweetest steviol glycosides found in the leaf, Reb D and Reb M. We separate the yeast from the Reb D and Reb M compounds during the purification process.”

An Alternative

Cargill emphasizes that it does not propose EverSweet as a complete replacer of leaf-based stevia ingredients. In fact, the company still offers and continues to grow its own portfolio of leaf-derived stevia ingredients, including its ViaTech line. The company also continues to work on breeding improved stevia leaves-and, in fact, Kennedy points out that Cargill’s expertise in growing canola crops also informs the company’s best practices for breeding stevia plants.

Instead of replacing leaf-based stevia, Kennedy says, “EverSweet is meant to open new market opportunities where stevia leaf extract does not play today. Our new sweetener will give consumers more options for great-tasting, reduced- and zero-calorie products.”

At the Natural Products Expo West trade show in Anaheim, CA, in March, Kennedy said the market could even see products launching with EverSweet in the next year or two. She added that, like with stevia sweeteners in general, beverages are often an easier place to start because, unlike with food products, formulators do not have to worry as much about the bulking properties and texture that are lost when replacing sugar with a high-intensity sweetener like stevia.

The EverSweet launch was postponed initially, chiefly because Cargill and Evolva needed to further improve the process’s glycoside yields and cost parameters, Kennedy told Nutritional Outlook at Natural Products Expo West. “Over time, we’ve increased the efficiency of the yeast turning basic sugars into steviol glycosides, as well as improved the efficiency of the purification step. This has allowed us to produce EverSweet sweetener cost-efficiently.”

Now, she says, “Cargill has achieved a suitable scale and cost-efficient supply of the sweetest steviol glycosides, Reb D and Reb M, through fermentation.”

Exploring All Avenues

Moving forward, Cargill’s stevia portfolio looks like it will comprise a combination of leaf-based stevia ingredients and stevia ingredients produced through alternative means.

Other industry leaders are also evaluating their own production processes. In April, PureCircle published a press statement noting that, in addition to focusing on extracting higher amounts of Reb M and Reb D from StarLeaf, the company is also exploring other avenues in an attempt to produce more of those glycosides.

In the statement, the company said it “now has two ways” of producing Reb D and Reb M. It said: “PureCircle continues to produce Reb D and Reb M by extracting them from its proprietary StarLeaf plants. But now it can also produce Reb D and Reb M in much greater scale, directly using the more abundant Reb A in the production process. The Reb D and Reb M produced from the two processes are from the stevia leaf and are identical in great taste.” Carolyn Clark, PureCircle’s director of global marketing, says that the details of the process involving Reb A are proprietary, but adds, “The most important takeaway is all the Reb M and D we produce are from the stevia plant and are identical in great taste.”

In its public statement, the company further noted that more consumer brands are “already using PureCircle’s Reb D and Reb M in their products” and that “PureCircle’s expansion in production of Reb D and Reb M will increase the supply of these stevia sweeteners with the most sugar-like taste.” The company said it’s already begun “ramping up” production of Reb D and Reb M, with PureCircle CEO Maga Malsagov stating that “large-scale volumes are now available at attractive prices.” 

“That will help the beverage and food companies get access to an ingredient they need, as they continue to respond to their consumers’ desires for more zero- and low-calorie products using plant-based sweeteners,” the company added.

To Market, To Market

As stevia suppliers introduce different types of Reb M and Reb D sweeteners, in the end, formulators-and, possibly, well-informed end-use customers-will determine which type is right for them. Each has its advantages.

For instance, Sweet Green Fields’ Francis says, “In the long term, it is likely that stevia sweeteners produced by fermentation and/or bioconversion may be lower cost versus traditional stevia extracts.” However, he says, “although bioconversion starts with the stevia leaf and converts to a targeted glycoside, fermentation is a completely different process” and that “to produce a stevia glycoside from fermentation does not even use stevia leaf whatsoever.”

Meanwhile, Kennedy says that EverSweet gives formulators who may have had trouble sourcing Reb M and Reb D another option. “What we’d been hearing from formulators is, ‘I really want to get my hands on Reb M or Reb D, but I can’t track any down from leaf,” Kennedy said at Natural Products Expo West. These formulators might now try EverSweet instead.

Companies also have another option for improving stevia-sweetener taste, which is to formulate with a blend of glycosides, both major and minor. As Layn’s Yu says, “Today, we are seeing more and more CPG companies combining multiple steviol glycosides because the combination provides a better customized sweet solution.”

Many stevia suppliers agree that blends are a good answer. This includes blends with various glycosides as well as with other kinds of sweeteners.

At Natural Products Expo West, for instance, Kennedy said that while EverSweet can serve as the sole sweetener in some product applications, “I think we’re going to see combinations with EverSweet”-such as those marrying EverSweet and leaf-derived stevia ingredients. Products containing both could be labeled as containing both “stevia leaf extract” and “steviol glycosides” (from EverSweet), she said.

“We have research that shows that when you combine stevia leaf extract with steviol glycosides on a label, there’s an overall improvement in purchase intent and the overall halo of healthfulness,” she added. Other Cargill sweetening ingredients, such as chicory root fiber, can also pair with stevia.

GLG/ADM point out that their high–Reb M ingredient “blends well with other sweeteners, such as monk fruit and sugar alcohols, to create balanced sweetness.”

As for PureCircle, Son says, “Through all of our research at the application level, we’ve found that a combination approach-blends of glycosides-is often what is most successful.”

She continues: “We have learned there is tremendous advantages to using the entirety of the stevia leaf in formulations. When blends of the individual stevia ingredients come together, they produce certain taste synergies, which can result in improved taste performance and negate the need for masking agents.”

Blends are also likely necessary, frankly, while suppliers work on optimizing Reb M and Reb D’s production and cost in use. Son says, “As we scale, these ingredients are going to become more readily available for use by companies operating globally or on a smaller scale.” In the meantime, she emphasizes, “We believe it is important to look at how combinations of various steviol glycosides can provide synergies and the most sugar-like taste within various applications. Often, it is blends of stevia ingredients which yield superior taste performance compared to single-ingredient solutions.”

And, lest we forget: applications expertise is also key. A supplier’s ability to pair the right type of glycoside and sweetener blend with the right type of product application in order to maximize efficacy as a sugar replacer is invaluable. Stevia suppliers with expertise offering specific sweetening solutions tailored to specific types of products, whether it be dairy products, beverages, or others, will find themselves a step ahead of the competition.

From Minor to Major

Within the stevia leaf is a world of sweetening possibilities waiting to be discovered. As stevia suppliers tap into the leaf’s next generation of steviol glycosides, they will continue teasing out better-tasting glycosides and figuring out ways to produce these glycosides at commercial scale. In short, one day, these minor glycosides could be major.

Son describes PureCircle’s dreams for the future stevia market, and it sounds like the dreams of many a stevia supplier. “Our vision has always been to create a global mass market for a natural-origin sweetener, and to make it affordable for global brands. The key to doing this is to increase the global supply of the very best-tasting stevia ingredients.”

If suppliers can figure out how to scale up supply of these glycosides in a way that’s successful in the market, there’s no telling how far stevia can go.


Also read:

How to Create a Reb A Stevia Ingredient That Is Still Affordable and Tastes Good

New Stevia Plus Allulose Ingredient Is Blood Sugar Friendly

Why Is Organic Stevia So Difficult to Achieve?

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