The most likely scenario is that U.S. sales of the sweetener -- formally known as rebaudioside A or Reb A -- will leap more than 50% within five years, from $455 million in 2008 (representing 35% of the global market of $1.3 billion) to $700 million, according to the report, "Stevia and the U.S. Market."

However, Reb A's performance could fall significantly above or below this projection, depending on several factors, Rabobank's researchers stress.

In a bullish scenario, Reb A has the potential to become "a mainstream sweetener with broad applications in the U.S. food and beverage industry," taking share away both from other high-intensity sweeteners (HIS) and high fructose corn syrup (HFCS), the dominant sweetener used in full-calorie carbonated soft drinks. In this case, it could grab as much as 15% of the HIS market and as much as 5% of the HFCS market, by volume, with annual usage reaching 5,600 tons and a value of $1.4 billion.

Currently, stevia sweeteners have a 1% share of the total U.S. HIS market, which is dominated by aspartame (43%) and sucralose (42%). Saccharine has just a 10% share.

In a pessimistic scenario in which Reb A fails to gain acceptance for mainstream beverage usage over the next five years, it would command no more than 5% of the HIS market by volume and have little effect on HFCS sales, say the researchers.

Cost and/or lack of sufficient uptake by consumers could swing the needle in the pessimistic direction. Cost-wise, Reb A is currently significantly more costly than sugar, and even more costly than HFCS. Soft drink makers have indicated that Reb A will be viable as a sweetener for mass products, such as soft drinks, only if its price drops by about half, to be equivalent to that of sugar, according to the report.

Cost depends on agricultural scale and efficiency and ability to keep up with demand. Most Reb A is currently produced by small farmers, and meeting demand in the U.S. and other regions quickly enough could pose a real challenge that drives costs even higher, at least in the short term, according to Rabobank. The good news for F&B makers using Reb A is that larger farmers are now gearing up for scalable production, two leading refiners, PureCircle and GLG, are investing in genetic development methods and, in the short term, PureCircle has offered to supply Reb A at sugar-equivalent prices.

However, until or unless the costs can be brought down to HFCS levels, F&B marketers' cost concerns will "not be fully resolved," the researchers point out.

As for taste, Reb A has the taste closest to sugar among HIS's, but "consistency of taste can vary substantially, and some consumers still claim to detect a bitter or licorice aftertaste that they find objectionable," says the report. In addition, Reb A isn't sweet enough on its own for carbonated soft drinks, but combining it with other non-caloric sweeteners makes it untenable to use the "all natural" claim that is such a big attraction for consumers and a driving force behind marketers' stevia push.

Therefore, many of the beverages being marketed -- PepsiCo's successful Trop 50 being a good example -- are combining Reb A and sugar, to enable keeping the all-natural claim while covering any potential aftertaste, Rabobank notes.

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