Be Wary Of New Natural Sweeteners

LAS VEGAS — Stevia and monk fruit are making inroads in product development, but other natural sweeteners tend to have significant defects, perhaps significant enough to keep them from ever reaching a commercial stage and becoming tools for sugar reduction, said John C. Fry, Ph.D, director of Connect Consulting.


“Not perhaps the cheery news you all were expecting,” he said in a June 27 presentation in Las Vegas at IFT17, the Institute of Food Technologists’ annual meeting and exposition. “Essentially we’re stuck with stevia and monk fruit for the time being.”

Dr. Fry has directed Connect Consulting, a technical resource for sweetener manufacturers and users, since 1997. In his IFT17 presentation he mentioned monatin and brazzein as two sweeteners facing obstacles.

“Monatin has an outstanding sweetness profile,” Dr. Fry said. “It really is on the same sort of quality as aspartame and sucralose, and it also has a very high potency. Its problem is, there are issues with safety, which means it is unlikely in my view that monatin will ever be a commercial sweetener.”

Monatin is derived from root bark in a spiky plant that grows wild, he said. It is not possible to cultivate the plant, which means monatin’s only commercial route as a sweetener would be through fermentation. 

Brazzein, sourced from an African shrub, has a decent sweetness potency and quality sweetness, although it is not in the same class as monatin, Dr. Fry said.

“It has atrocious dynamics, by which I mean the way the sweetness is perceived in terms of onset and linger,” Dr. Fry said. “In the case of brazzein, the onset is remarkably long. You’re talking about maybe 4 or 5 seconds for it to achieve peak sweetness.”

Brazzein, because of the onset problem, has no future as a standalone sweetener and only would work in sweetener blends, he said.

“Given its lack of a future as a standalone sweetener, one must wonder if brazzein is ever going to attract the level of funding necessary to do the safety tests on it,” Dr. Fry said. 

Besides monatin and brazzein, other natural high-potency sweeteners exist.

“The general tenor of many of these reports (on the sweeteners) is, ‘This thing is potently sweet. It’s natural. It must therefore have a glowing commercial future,’” Dr. Fry said. “And that, of course, is not the case, and, if you examine many of these compounds, you will find that they have significant defects.”

In contrast, stevia and monk fruit are finding commercial success despite facing their own obstacles. Recent research has focused on two steviol glycosides, Rebaudioside D and Rebaudioside M, in the stevia leaf. Reb D and Reb M outperform Reb A in sweetness intensity, but they both have low concentrations in the stevia leaf, Dr. Fry said.

“Particularly in the case of Reb M, it’s currently hardly economically feasible to isolate Reb M as a commercial ingredient from the leaf,” he said. 

Attempts to make Reb M and Reb D more commercially feasible fall into three types, he said. One, plant breeding, seeks to create stevia plants with higher yields of Reb M and Reb D, but this effort could be 8 to 10 years away from any success, Dr. Fry said. Fermentation, a second type, involves transferring genes from Reb M into yeast. The third type, bioconversion, involves taking a low value steviol glycoside such as stevioside and using specific enzymes to convert it into Reb M.

“Of those, fermentation is almost certainly going to be the lowest cost route,” he said.

Although they offer a high sweetness intensity, Reb D and Reb M each have their own defects.

“Reb D has a significantly delayed onset, and Reb M is one of the worst steviol glycosides for a prolonged sweet taste,” Dr. Fry said. 

Blending the two steviol glycosides may solve problems.

“The effect of mixing Reb M and Reb D is to enhance the general potency while actually significantly reducing the (off) taste,” Dr. Fry said.

Synergistic blends involving steviol glycosides such as Reb A, Reb M, Reb D and stevioside are leading to greater sugar reductions in foods and beverages.

“The synergistic blends of steviol glycosides owe their origins to greatly increased understanding of the interactions between steviol glycosides capable of producing benefits, by which I mean enhanced sweetness and reduced, unwanted side effects, typically acute bitterness and acute licorice,” Dr. Fry said. “Surprisingly perhaps, blends of steviol glycosides are capable of outperforming high-purity glycosides such as Rebaudioside A.” 

He said Reb A in a lemon lime carbonated soft drink created an acceptable taste with 50% sugar reduction, but a synergistic blend of steviol glycosides led to an acceptable taste with 75% sugar reduction.

The sweetness of monk fruit comes from compounds called mogrosides inside the fruit. Mogroside 5 tastes like Reb M, Dr. Fry said. The mogrosides, however, are pH-sensitive, which means monk fruit works better in neutral pH applications.

“The principal issue with mogrosides is that it is a costly sweetener,” Dr. Fry said. “It is significantly more expensive than stevia.” 

Stevia and monk fruit often are blended in a ratio of two parts stevia to one part monk fruit, he said.

“That is said to improve the taste quality of steviol glycosides while mitigating the cost effect of monk fruit,” he said.