The use of Stevia (EU) as a natural high-intensity sweetener is expanding as consumers look for naturally sweetened products with less calories from sugar, while still expecting a high-quality taste experience. Mintel reported new Stevia product launches have grown globally over the last few years. With some formulation work, Stevia may enable your product to join the ranks of “reduced sugar” with high consumer acceptability.
What is this natural sweetener?
Steviol glycosides (EU) are a group of 10 compounds, commonly called Stevia, which are extracted from the leaves of Stevia rebaudiana Bertoni (EU), a native plant found along the border of Paraguay and Brazil. Roughly 200 times sweeter than sucrose and non-caloric, Stevia performs best at a pH between 4-8, and appears stable with light exposure, through high-temperature, short-time processing, and in many product categories over shelf life.
Every sweetener has an “appearance time” and “extinction time.” In studies comparing the sweetness temporal profile (sweetness intensity over time) of rebaudioside A (EU) with sucrose (EU). Sucrose has a faster appearance time, but rebaudioside A has a longer extinction time, which would be beneficial for products requiring prolonged sweetness.
Comparison of Steviol Glycosides and Sweetness Potency (Sucrose= 1)
Nabors, L (2012) Alternative Sweeteners, 4th Ed. Boca Raton: CRC Press.
While Stevia plants have sweetened foods in South America for centuries, and countries like Japan have used Stevia for decades, steviol glycosides only received regulatory approval in the EU in November 2011 and in Canada in November 2012. Within the US, the CFR does not include Stevia products within approved food additives, and Stevia leaves and low-purity Stevia extracts are not considered GRAS and are prohibited from use in food. However, since 2008, GRAS Notices have been submitted without questions back from the FDA for high purity (95% min) steviol glycosides like Stevioside (EU), Rebaudioside A, Rebaudioside D (EU) or other mixtures of pure steviol glycosides. An Adequate Daily Intake (ADI), set by both JECFA and EFSA, is 0 – 4 mg/kg body weight (expressed as steviol).
Strategies to minimize bitter notes
Within food systems, Stevia is often associated with bitter and/or black licorice off notes. Stevia is a relatively new ingredient and within the last 45 years, the ingredient has undergone a lot of research and refinement. So, if you have previously tried Stevia extracts without success, with some of the newer research and next generation Stevia extracts on the market, you may find Stevia will work for your product system now.
An explanation of sucrose equivalents (SE) in The Sweetener Book by D. Eric Walters states that “coffee is typically sweetened to about the level of 5% sucrose. Soft drinks are usually about as sweet as 10% sucrose.” When using Stevia to replace sucrose in a food system, usage levels under 6% SE results in a sweet profile without noticeable off notes. However, using Stevia above 6% SE can result in bitter and/or licorice off notes.
One solution is to use Stevia in combination with other sweeteners to achieve an SE above 6%. Non-caloric combinations that have shown potential include: erythritol (EU), aspartame (EU), acesulfame potassium (EU), saccharin salts (EU), or sucralose (EU). However, blending Stevia with a small amount of carbohydrate sweeteners like sucrose can enable a product with calorie reduction and a sweet temporal profile nearly matching sucrose without off notes.
Another solution is to choose pure extractions of rebaudioside A, because it is inherently less bitter and can be used at a lower level to achieve the same sweetness when compared to Stevioside. However, ingredient suppliers also have created next generation Stevia ingredients with a composition of pure steviol glycosides with less bitter results. There are also some manufacturers using enzyme technology to reduce the bitter compounds of Stevia. As research continues on the different compounds and human bitter response, future Stevia extractions will continue to improve.
Lastly, in growing Stevia plants, farmers and horticulture researchers are using selective breeding to increase the sweet and reduce bitter compounds to enable Stevia manufacturers to produce a better raw material for the food industry. Rebaudioside D, for example, offers a sweet profile without bitter compounds but it currently only makes up a small percentage of the Stevia plant, so it is not a commercially viable option as a pure isolation.
In the world of clean labels and increasing consumer preference for low calorie products, Stevia can offer a natural sweetness solution. And with development of next generation ingredients and a continued research focus, Stevia may be used successfully to naturally sweeten your product without the historically prevalent bitter off-notes.
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