R&D: Stevia Sweeteners: Quality Matters -- November 2009

Rebaudioside-A (Reb-A), a new sweetener extracted from the stevia plant, is taking the food industry by storm. It offers the first natural, zero-calorie, high-intensity sweetener that is stable to a wide range of temperatures and pHs. While the stevia plant contains 11 glycosides, GRAS status requires purity of only Reb-A, one of the sweetest and best-tasting steviol glycosides, at a minimum of 95%. As a natural product, the other 5% of the extract is variable and includes different amounts of glycosides, with differing levels of sweetness and bitterness. The composition of the remaining 5% of the Reb-A extract may adversely affect the flavor in finished products. For example, Reb-B and Reb-C are glycosides known to contribute bitterness; this can be an issue with some stevia products on the market.

It is for this reason that consistent quality of Reb-A is extremely important. According to Sidd Purkayastha, technical director at PureCircle, “The product developers we work with recognize the right level of purity of Reb-A is essential, but consistency is of equal importance.” At PureCircle, scientists have developed a process to ensure Reb-A purity levels of greater than 97%, a level that their sensory analysis has shown provides excellent flavor, while keeping bitterness at bay.

Consistent Quality
Extracting product of a consistent quality at a standard purity level might seem like a fairly easy task. However, given the natural compositional variation in stevia extract, producing consistent quality in large batches is a key challenge in the industry. In small batches on a bench top or in a pilot plant, it is much easier to control product quality, because the variation in a small batch is inherently lower. But, once there is the necessary scale-up to larger batches, this is not the case.

“Customers expect us to be able to deliver to tight quality specifications with every batch,” explains Jason Hecker, marketing director at PureCircle. “Time and again, we must be able to deliver very high quality Reb-A. The product must be produced not only to our own specifications, but also to independently verifiable standard levels.”

To achieve these quality standard levels, PureCircle is involved in every step of the supply chain, working directly with farmers--educating them on growing methods, while developing proprietary strains of stevia. Having control, from leaf to final product, ensures consistent quality. “As a result, we can produce in very large, 5 MT quantities,” says Hecker. “A batch of Reb-A this large is enough to assure that nearly 26 million cans of soda could come from the same production run.”

In the end, it is important for food and beverage manufacturers to remember, when sourcing a stevia-based sweetener, to check not only the percentage of purity (95% or above), but also whether the supplier can produce consistent quality on a large scale. Otherwise, there may be uncontrollable variability in the end-product. pf

--Elizabeth Mannie, Contributing Editor

For more information:
PureCircle USA Inc. • Oak Brook, Ill.
Jason Hecker • Jason.Hecker@purecircle.com