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Stevia & Rebaudioside A (non-caloric natural sweetener) by Paul Burns
Issue Date: April / May 2009
Stevia rebaudiana, an herb native to Central and South America, has been cultivated for decades for its sweet tasting leaves. Extracts and refined Steviol glycosides, derived from the leaves, have been used as a zero-calorie sugar substitutes since the early 1970’s. In the US, Stevia has been approved for use as a dietary supplement since the mid 1990’s.
One of the major compounds of Stevia is Rebaudioside A (Reb A). It is 200 – 400 times sweeter than sucrose, heat stable, pH stable, and non-fermentable. Recently the FDA issued no objection to GRAS (generally regarded as safe) status for Reb A for use as a general-purpose sweetener in foods. This status opens the doors for its use in a variety of products including: beverages, candies, yoghurts, ice creams and baked goods. It is estimated that Reb A will grow to 20-25% of the world sugar and sweetener market.
The FDA, in its response letter GRAS Notice No. GRN 000253, clarified that Reb A is a “highly purified” compound derived from the Stevia plant and goes on to state that this status did not necessarily apply to other Stevia products. This leaves us with a few very important questions.
- Identification: How can a highly purified raw material be judged as “naturally” derived from Stevia after the fact?
- Purity: At what purity will this GRAS classification be applicable and when will it not?
- What testing method is available?
Testing Stevia & Reb A with Eurofins:
1) Identification: (by HPLC) Concerns have been raised about verifying the claim that a Reb A raw material is derived from Stevia rebaudiana. Although no synthetic manufacturer of Reb A has stepped forward they may not be far behind. One approach is testing for the numerous other steviol glycosides that are present in Stevia extracts, including “highly purified” extracts, since they are unlikely to be created synthetically.
2) Purity: In the FDA response letter, the FDA noted Cargill provided specifications for Reb A and that they were comparable to the specifications suggested by the FAO/WHO Joint Expert Committee on Food Additives (JECFA) at their 68th meeting in June 2007.
Assay:
Rebaudisoide A > 97% dry weight
Limits:
Other steviol glycosides < 3% dry weight
Moisture - not more then (NMT) 6%
Residual solvents:
Methanol - NMT 200 ppm
Ethanol - NMT 5000 ppm
Using sources of Reb A with purities of less then what is stated in the GRAS notice may run afoul of the FDA’s GRAS determination so knowing/verifying the purity is important.
For more information on this service, please contact Paul Burns at 707-792-7300.
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