In patent application #13605644, which you can read here (filed in Sept 2012, published in March 2013), PepsiCo describes a series of cola-type beverages and concentrates sweetened with Reb-D with a purity of 93-99%, used on its own or in combination with other high intensity or/and bulk sweeteners.
Reb-D exhibits ‘significantly lower bitterness than Reb-A’ in diet carbonated cola drinks
In the book ‘Stevia: the genus stevia’ edited by A. Douglas Kinghorn, Reb-D was described as being around 10% less sweet than the best-known steviol glycoside Reb-A.
However, it has since been “unexpectedly discovered that rebaudioside D in an aqueous solution, an acidic aqueous solution, and an acidic aqueous carbonated solution, provides the same or significantly higher sweetness than the same concentration of rebaudioside A in otherwise identical formulations”, says PepsiCo.
“This is in surprising in view of the teaching of Kinghorn that rebaudioside D provides a lower sweetness than rebaudioside A.”
Meanwhile, it has also been “unexpectedly discovered that rebaudioside D in an aqueous solution, an acidic aqueous solution, and an acidic aqueous carbonated solution provides significantly lower bitterness than the same concentration of rebaudioside A in otherwise identical formulations”, adds PepsiCo.
Off-tastes of Reb-A ‘tend to be more perceptible in diet carbonated cola soft drinks’
While Reb-A is typically present in the stevia leaf in higher quantities (2-4% by dry weight) than other glycosides, it creates “off-tastes in many beverage formulations, especially… carbonated cola flavored beverages, for example slow on-set of sweetness, bitter aftertaste, licorice taste, and/or lingering aftertaste”, says PepsiCo.
And these off-tastes “tend to be more perceptible in diet carbonated cola soft drinks sweetened with Reb A than in other beverage formulations”, adds the soft drinks and snacks giant, which uses stevia in combination with other sweeteners in its Pepsi Next reduced sugar cola in Australia (but not in the US version).
However, it has not - yet - launched a zero calorie 'diet' cola with stevia.
Reb-D has a more desirable taste profile than Reb A
Reb-D, meanwhile, “has a sweetness intensity similar to Reb A, but has been found to possess a more desirable taste profile than Reb A and many of the other steviol glycosides in cola beverage products” and is in general “more organoleptically pleasing”, it says.
Diet colas sweetened with Reb-D also have a “sweetness more like that provided by sucrose than do beverage products sweetened with Reb-A” it adds.
PureCircle: Reb-D has "generated interest among a number of customers"
According to stevia supplier PureCircle, which has developed proprietary varieties of stevia plants containing high levels of Reb D, it has "one of the best sweetness profiles of any steviol glycoside”.
The firm, which has also secured process, method and application patents to protect its Reb D extracts, including a suite of more than 25 patents and patent applications for the ingredient, recently submitted a GRAS (Generally Recognized As Safe) notification for its high-purity Reb D to the FDA for review after an independent panel of experts deemed it to be safe.
Substantial investments are focused on scaling this new technology
Vice president global marketing & innovation Jason Hecker told FoodNavigator-USA that PureCircle's Reb-D had "generated interest among a number of customers" although he was not able to name names.
He added: "Given its clean profile, PureCircle Reb D will be particularly important in enabling customers to develop naturally sweetened formulations with very low to no calories, particularly in food and beverages with higher sweetness levels, like carbonated soft drinks."
PureCircle is now "collaborating with several customers on product development, with primary focus on initial introductions in the United States”, says the firm.
“Substantial investments are focused on scaling this new technology.”
Asked whether Reb-D is approved in Europe, Hecker said: "Reb D is included among the steviol glycoside recognized as part of the current European approval, however at this time it not approved for sale as a standalone food ingredient."
Click here to read more about Reb-D.