Kantha Shelke, PhD, takes on stevia

4 Min Read
Kantha Shelke, PhD, takes on stevia

FI: In the evolution of stevia, the early pioneers worked mostly with the refined whole leaf (steviosides), today there is a constant retooling of RebA. Can you talk about the differences between the various forms of RebA and the early forms of stevia?

KS: Stevia, the South American ethnobotanical Stevia rebaudiana (Bertoni) regarded as a counter-culture herbal ingredient in the US and Europe until late last year, may be found in the US market in a number of avatars including naturally water extracted, hexane extracted, and enzymatically produced formats.

Stevia is the common name of the plant and has come to refer to the sweetener as well. Stevioside is another name for these sweeteners and includes Reb-A, B, C, D and E; dulcoside A; and steviolbioside. Steviol glycoside is a more precise term and includes steviosides and rebaudioside A (Reb-A).

In the 1970s and 1980s the stevia that appeared in herbal and "health-food" stores in North America and Europe was mostly as crushed leaves. The US FDA repeatedly rejected requests to market stevia as a food additive. The Dietary Supplement Health and Education Act (DSHEA) in 1994 (USFDA, 1995) allowed the marketing of leaves or leaf extracts but only as a dietary supplement. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) established temporary specifications and a temporary ADI for steviol glycosides of 0— 2 mg/kg bw/day expressed as steviol using a safety factor of 200.

Legally, in the US, only those preparations of Reb-A supported by GRAS status — self-affirmed or notified — may be marketed in foods and beverages. Formulators can look forward to a number of Reb-A enhancers in the near future.

There is RP44 — a natural sweetness enhancer which in combination with Reb-A can reduce up to 50% of the caloric content of sugar-sweetened products without losing the taste quality of the fully sweetened product. Evaluation is underway at major ingredient suppliers and food and beverage companies of RP44 in different taste systems. RP44 maker, Redpoint Bio, is actively seeking a commercial partner even as it is testing the economics and commercial viability of RP44 and of course, safety testing for the GRAS determination/notification process.

Also in the pipeline is S6973, a novel sweetener enhancer for Reb-A from Senomyx in collaboration with Firmenich. Firmenich expects to conclude its commercial feasibility testing of S6793 in early 2010.

FI: In 2009, the race for stevia was dominated by the tabletop market. For 2010, it is believed that beverage manufacturers such as Coke and Pepsi will begin introducing new stevia sweetened beverages in the US market. How will this affect supply (ie, is there enough to go around)?

KS: The tough economy may have been a blessing and deterred the flippant flooding of the market by poorly thought out products containing rebaudioside-A (Reb-A). Many even bet their last dollar and shirt on the second coming of sugar in the form of stevia.

In fact, confidence was so high that Reb-A would be granted Generally Recognized As Safe (GRAS) status that Cargill launched Truvia even before the FDA officially blessed Reb-A with a GRAS status for tabletop applications. Several GRAS petitions later, the US tabletop market is now fraught with choices for 'naturally' sweetening tea and coffee. Even McNeil Nutritionals, the co-developer of Splenda, got in on the act with Sun Crystals All-Natural Sweetener, a Reb-A, sugar blend. While the US retail market boasts at least 20 different brands of Reb-A tabletop sweeteners the restaurant and food-service industry has not embraced it.

The greater opportunity is obviously in beverages, but whether the current supply can meet the demands alone is questionable.

Coca Cola and Pepsi, supported by vertical integration with Reb-A suppliers PureCircle and GLG Life Tech, launched several new beverages including Trop50, Vitaminwater Zero, Sprite Green, All Sport Zero, Aquafina Plus Vitamins 10 Cal and SoBe Lifewater. Conspicuously, there is no Reb-A Coke or Pepsi or even Cherry Coke or Mountain Dew in this line-up. For good reason — marketers need more assurance that consumers will embrace the new sweetener! Other major beverage brands lacking vertical alignment are rightly cautious launches.

Reb-A begins with a stevia leaf, its supply is contingent upon the strength and yield of the crop. It will be some time before the crop can adequately spread the sweetness around.

FI: What about adulteration of Reb-A?

KS: "None of us likes to be swindled, particularly when all we were trying to do was buy something nice to eat," to quote Bee Wilson in her book Swindled: The dark history of food fraud, from poisoned candy to counterfeit coffee.

The wholly disagreeable feeling of mortification mingled with fury is regrettably one of the universal human experiences that is bound to be experienced repeatedly in the near future by companies attempting to formulate with Reb-A. Given the popularity, cost and paucity of quality Reb-A, caution demands that one be prepared for industrial-scale adulterations. The situation will likely worsen with increasingly sophisticated scams in step with the increasing scientific ability to detect and combat adulterations — especially in the event of inclement weather conditions in the stevia growing regions. I suggest what Kevin Li, chief technology officer, GLG Life Tech Corp, says: "All companies independently test all ingredients."

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