Where next for stevia? From designer glycoside blends to fermentation and enzyme modification

01-Mar-2017 - Last updated on 18-Mar-2017 at 02:20 GMT

If high purity Reb A used to be the only game in town when it comes to stevia, the game has become a lot more sophisticated in the past couple of years as suppliers compete to provide the best-tasting combinations of steviol glycosides, and products become more application-specific, says Sweet Green Fields chief science officer Mel Jackson PhD.

With added sugar now public enemy #1, soda taxes gaining traction, and added sugar labeling on the horizon, the pressure on manufacturers to reduce sugar is ratcheting up all the time, and manufacturers are looking for more tailored, but cost-effective, solutions, Dr Jackson told FoodNavigator-USA.

There is also an acceptance that aside from monk fruit, which remains expensive, there are not actually many options in the natural sweeteners space aside from stevia that are commercially viable right now, he added.

“There have been no huge step changes, all of the progress in the last couple of years has really been going beyond Reb A [the most abundant steviol glycoside – or sweetening component - in the stevia leaf] and looking at how the different glycosides work together to get a more sugar-like taste.”

Designer blends

At Sweet Green Fields, which merged with its long-time supplier Zhejiang Green World in 2015 to become one of the largest, privately held, fully-integrated stevia ingredient companies in the world, a lot of work has been devoted to engineering the extraction process such that it yields a specific combination of glycosides, rather than individually extracting glycosides, purifying them, and then recombining them, said Dr Jackson.

“We have been using technology that enables us to selectively enhance stevia extracts by engineering the extraction process to get to a desired combination of steviol glycosides straight from the extraction, rather than re-combining individual purified steviol glycosides. We are creating a designer blend, if you like.

“So our Intesse line produces a stevia that is very sugar-like without the typical bitter lingering you get with stevia extracts… A new line of products we are about to launch also reflects this technology and really tastes extraordinary.”

He added: “I think a lot of our competitors are re-combining individual purified steviol glycosides, which has some benefits, but there is a cost to that, and also differences in taste because our products contain minor glycosides that are not in their combinations.”

Enzymatic modification

But what about enzymatic modification, which appears in a growing number of stevia-related patent applications?

“Everyone is dong slightly different things,” explained Dr Jackson, “But using enzymes to create natural flavors from stevia has been going on for years, especially in Japan and Korea. Here, you can use enzymes to transfer glucose molecules from starches to steviol glycosides.

“In the US, FEMA [the Flavor and Extract Manufacturers Association] gives enzyme modified steviol glycosides their own category (FEMA GRAS 4728 - Glucosyl steviol glycosides). If you use them below a certain threshold, they can alter your perception of sweetness or enhance sweetness, but they are not acting as sweeteners, so you can call them ‘natural flavor’ on the label.

“And if you already have natural flavors on your ingredients label, you don’t have to add anything at all, which is obviously appealing as people look for shorter cleaner labels.”

If you go above that threshold and your enzyme-modified product is functioning as a sweetener, he said, “it would have to be described as enzyme modified steviol glycosides, or some equivalent, and it has to be FDA GRAS [generally recognized as safe], so there is a different path.

“Some companies have done that [for example, PureCircle has enzyme modified sweeteners - Glucosylated Stevia Leaf Extracts - in its 'Zeta' portfolio, while GLG Lifetech received a letter of no objection from the FDA to its GRAS determination for enzymatically modified stevia product EMS95 in October 2016], but the products are not always as potent.”

“Initially there were many many companies competing in the stevia space, while today there are a handful of major players such as Cargill, PureCircle and Sweet Green Fields who dominate most of the space in the US, but there are lots of small traders especially coming out of China that are selling low to mid-grade Reb A, so RA 50, RA 60, RA 80, but the popularity of these commodity products is declining.

“Other players such as Almendra are trying to differentiate themselves with high purity Reb A, while at Sweet Green Fields, our proprietary compositions are accounting for an increasing percentage of our sales.

Mel Jackson, PhD, chief science officer, Sweet Green Fields

Stevia... minus the leaf?

As for ‘fermented’ steviol glycosides such as EverSweet – in which a genetically engineered baker’s yeast converts sugars (from corn dextrose) into the best-tasting glycosides Reb D+M via a fermentation process – the technology is exciting, he said.

However, no products are on the market yet, and it is unclear how the market will respond, given that the primary reason that food and beverage manufacturers started experimenting with stevia in the first place was precisely due to its ‘natural’ credentials (it’s from a leaf), he observed.

In other words, if you take the stevia leaf out of the equation, you’re in something of a grey area in terms of food marketing, even if the final product is chemically identical to Reb D+M from a leaf.

While EverSweet could be labeled as Reb M and Reb D, steviol glycosides, or Rebaudioside M and Rebaudioside D, none of these are as consumer-friendly as ‘stevia leaf extract,’ he argued.

“Maybe some companies will list it as ‘steviol glycosides’ on the ingredients list and hope that consumers don’t really differentiate between that and stevia [from the leaf]; they may hope that there will be a halo effect from stevia and the leaf, but I don’t know. To many consumers, ‘steviol glycoside’ probably sounds like a chemical.”

Organic stevia

Asked about organic stevia, which is offered by Sweet Green Fields, he said: “Very few other players are offering what I would call truly organic stevia. The organic auditor/certifier must understand exactly what is going on at every stage of the process [crop growing, extraction, clarification, concentration, chromatography, crystallization etc] and we know that that is not always the case, and at times the organic auditor could be misled.”

For example, during the flocculation process, in which crude stevia extracts are clarified, he said, “many flocculants are not organic compliant. Solvents can also be an issue.”

Rapid growth for Sweet Green Fields

As a private company, Sweet Green Fields does not share revenues, but it is growing rapidly, claimed Dr Jackson.

“We are growing very quickly now. I think that finally the public and beverage companies have gone through the first stages of understanding the potential of stevia and now we are seeing that reflected in our sales.

"I would also urge all manufacturers that have tried stevia in the past to keep revisiting it, because in some applications, it really is indistinguishable from full sugar now.”