How do you secure a consistent source of stevia and the right bulk sweeteners to pair with it?26 April 2012
The EU approval of stevia – Europe’s first naturally derived high intensity sweetener – last November was hailed as a massive regulatory milestone with the potential to change the way food and beverage products are sweetened in Europe.
This may be true but stevia is not going to achieve market domination overnight. The road to developing stevia-sweetened products is long and wrought with regulatory and technical hurdles.
Steviol glycosides are high-intensity sweeteners meaning they are hundreds of times as effective as sugar on a weight basis. All high-intensity sweeteners are only used in tiny amounts because they are so potently sweet. In this respect stevia presents a similar challenge to synthetic high-intensity sweeteners like aspartame, acesulfame K and sucralose – that of replacing the bulk provided by sugars.
“In the case of steviol glycosides the solutions – where required – are similar to those for other high potency sweeteners, except that there is obviously a preference for natural bulking agents,” says John Fry, director of Connect Consulting and principal consultant to Cargill Health & Nutrition, supplier of stevia under the Truvia brand.
According to Cargill’s arch rival PureCircle, stevia works well with polyols and other oligosaccharides which replace sugar’s bulking quality.
In the US the zero-calorie sugar alcohol erythritol has proved to be one of the most popular polyol partners for stevia. Cargill’s table-top sweetener Truvia, which commands 13% of the US sugar substitute market, is a combination of erythritol and stevia.
“In the US erythritol is considered natural and this polyol is an ideal blending agent for steviol glycosides. Erythritol not only has zero calories but displays qualitative synergy with steviol glycosides, improving the taste profile markedly. It is a bulk sweet-ener, so can also contribute to bulk replacement,” explains Fry.
Jungbunzlauer has developed an erythritol and stevia blend branded Erylite. A spokesperson for the company explains why erythritol and stevia make such a good team.
“The blend of Erylite and rebaudioside A is highly synergistic. Rebaudioside A brings an off taste along with the sweetness and has no bulk. Erythritol in turn has a sweetness level of 50% compared to sugar but is a bulk sweetener and has a strong taste enhancing effect, as well as eliminating the off taste and lingering sweetness,” says the spokesperson.
Jungbunzlauer says the advantage of using Erylite Stevia rather than the two individual sweeteners is that it is easier to use and ensures accurate dosing – one of the main problems with high-intensity sweeteners.
Erythritol also offers an advantage over other polyols in that it is the only sugar alcohol that is classed as zero calorie in the EU.
“All other polyols have a minimum of 2.4kcal/g, allowing a maximum reduction of 40% sugar calories when used as a sugar replacer. In addition, erythritol is much more tolerable to the human digestive system – no laxative effects are observed at typical consumption levels,” says the spokesperson.
As to whether the natural status enjoyed by erythritol-stevia blends in the US also applies in the EU, Jungbunzlauer believes it does.
“After a thorough review we are convinced that a natural labelling is acceptable for Erylite Stevia. This is based on the fact that Erylite Erythritol is obtained by yeast fermentation and that stevia extracts are a plant based product,” says the spokesperson.
So far, Jungbunzlauer reports success with Erylite Stevia in table-top sweeteners, yoghurts and confectionery.
Isomalt meets its match
Isomalt is another polyol that is emerging as a good match with stevia particularly in confectionery products.
“Isomalt is derived from sugar beet, which means it has a sugar-like sensorial profile, but it delivers a milder sweetness than sucrose – around 50%,” says Dr Thomas Walter, head of new business development at Beneo. “The sweetness gap is filled with stevia so you end up with a very sugar-like taste profile, no bitterness and no off tastes, and the bulk gap is filled with isomalt, which provides mouthfeel and texture that stevia alone does not offer.”
Combining stevia and isomalt results in technical, as well as sensorial benefits, according to Dr Walter. “Isomalt is non-hygroscopic, which prevents stickiness and ensures shelf-life stability for confectionery and chewing gum products.”
Furthermore, he points out that isomalt enables manufacturers to adopt a tooth-friendly positioning.
Dr Walter says that development activity involving isomalt-stevia systems started a long time before EU approval of stevia was granted. It is not surprising, therefore, that several manufacturers have already launched products sweetened with stevia and isomalt.
For example, at the start of 2012 the sugar-free variant of Pulmoll, the German hard-boiled candy, was relaunched with a new recipe. Pulmoll is now sweetened with stevia rather than acesulfame K and aspartame which has enabled it to change its slogan to ‘Naturally Pulmoll – the soothing little helpers’. Isomalt and stevia are also being used to sweeten Villars, the sugar-reduced chocolate from Switzerland.
There are, however, some limitations to the use of stevia in conjunction with polyols like isomalt and erythritol, the main one being EU legislation that prevents the inclusion of polyols in beverages. This means that options for soft drinks are limited to using stevia either as a single sweetener, in combination with artificial high-intensity sweeteners, or with sugars.
Stand alone stevia?
According to Fry, in the US, a number of drinks companies are successfully using stevia as a single sweetener. However, he concedes that this only really works for drinks that require a low level of sweetness, such as vitamin waters and flavoured waters, as for most soft drinks the amount you would need to use would exceed the acceptable daily intake.
“Consequently blending steviol glycosides together with reduced amounts of sugar may become the norm,” he says. “This is advantageous as steviol glycosides blend particularly well with other sweeteners, and careful formulation can achieve sugar reductions of 30-50% that consumers like just as much as full-sugar versions.
“This approach has been successful in the USA where juice-based drinks sweetened with a combination of fruit juice and stevia are a real hit.”
Here again, though, manufacturers must be careful to take into account regulatory considerations – in the EU the use of stevia in combination with sugars is only permitted if it results in a calorie reduction of at least 30%.
Besides promoting a calorie reduction, beverage manufacturers may also be able to make a tooth-friendly claim if they opt for Beneo’s ‘next generation carbohydrate’ Palatinose (isomaltulose) – the first sugar to have tooth-friendly credentials.
Derived from beet sugar, it is a white, crystalline powder which gives the same energy as sugar and a similar sweetness. Beneo says it has trialled Palatinose in conjunction with stevia in tooth-friendly iced tea drinks (both ready-to-drink and powder formats) and found it to deliver a masking effect and good mouthfeel.
Taking the fruit route
Another alternative to conventional sugars that lends itself to combination with stevia is the natural fruit extract Fruit UP from Wild.
“Fruit UP is entirely extracted from fruit in a physical production process that uses no additives, chemical or otherwise,” explains Silke Ortmann, product manager at Wild. “In contrast to the production methods of other sweetening options, the manufacture of Fruit UP involves no enzymatic treatment at all. As such the product satisfies consumer requirements and is the ideal sweetener for clean label products.”
She says possible applications include fruit-containing beverages, smoothies, lemonades, sports drinks, near water beverages and herbal or tea drinks. In addition it can be used in dairy, bakery and confectionery applications.
Wild has also developed ‘Taste Optimisation Technology’ which it says eliminates the characteristic liquorice nuance and partly bitter aftertaste of stevia.
While Fry maintains that the real blending opportunity for stevia is with sugars, unlikely as it might sound, he says some manufacturers are looking to blend stevia with synthetic sweeteners.
“There is some demand to remove aspartame, despite its safety and efficacy,” he says. “This could result in blends of stevia with acesulfame K or saccharin being considered.”
In some cases, he says it is the other way round, with manufacturers seeking to replace one or both of the latter sweeteners with a combination of stevia and aspartame.
“There is certainly pronounced quantitative and qualitative synergy between reb A and several synthetic sweeteners, such as aspartame, that makes such blends attractive.”
Of course developing good tasting stevia sweetened products isn’t just about finding the right blending partners to provide bulk and mask off flavours – it is also about selecting the right steviol glycosides in the first place.
“Significantly, the quality of the extract and the amount of individual steviol glycosides used can have a major effect on the flavour of the end product: depending on the formula, this can result in a liquorice nuance and slightly bitter aftertaste,” says Wild’s Ortmann.
Her observations are backed up by John Fry, who notes “the degree to which steviol glycosides exhibit non-sweet side tastes depends on the glycoside and the amount used.”
The EU requires that steviol glycosides supplied as food ingredients are a minimum of 95% steviol glycosides and that the glycosides comprise at least 75% of reb A and stevioside (either or both) – the two main glycosides in the leaf. Within those limits any variation is possible and in practice, Fry says, products range from virtually pure reb A (95% or more) to those high in stevioside.
He says reb A is widely considered to be the best tasting of the major glycosides in the leaf, and high reb A content is associated with the best taste performance.
However, he argues that in fact, consistency of supply is a more important criterion.
“The EU has quite complex rules controlling the maximum amount of steviol glycoside allowed in any particular product and the calculations depend on the exact composition of the ingredient. Once you have set your formulation you don’t want lot-to-lot variation in glycoside composition to jeopardise either the taste or legality of your product.”
PureCircle’s VP global marketing and innovation, Jason Hecker, also highlights variability as a potential issue with stevia. “As stevia is a naturally derived ingredient, this variability can begin with the plant and continue through to the finished product. Manufacturers must evaluate several factors to ensure a stevia supply with consistent quality, quantity and taste.”
He says PureCircle has a vertically integrated supply chain from plant breeding to finished product for a scalable, reliable and safe supply of high-quality stevia products.
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