New research published in the International Journal of Food Science and Technology found steviol glycosides, the sweet components present in the leaves of the stevia plant, are not altered during the extraction and purification process to make high purity stevia extract. The study, published on June 19, 2017, was conducted at the University of Bonn in Germany, and provides further evidence for the naturality of stevia, a zero-calorie, plant-based sweetener.
 
To date, more than 40 different steviol glycosides have been identified in the stevia plant. All 40 plus steviol glycosides have U.S. GRAS (Generally Recognized as Safe) status, have been approved by Health Canada, Food Standards Australia New Zealand (FSANZ), and most recently by the Joint Expert Committee on Food Additives (JECFA). While the European Food Safety Authority (EFSA) is evaluating the approval of all 40 plus, they currently specify the use of 11 steviol glycosides in high purity stevia leaf extracts.  
 
This is the first study to systematically determine whether steviol glycosides are modified by the typical commercial extraction and purification processes used to obtain high-purity steviol glycoside sweeteners.  The study investigated whether commercial-scale extracted and purified steviol glycosides contain the same steviol glycoside pattern that is found in untreated leaves and the first water extract of stevia leaves, focusing on the nine steviol glycosides in the original JECFA specification (JECFA, 2010).
 
Samples of three independent commercial-scale batches of stevia leaf, provided by PureCircle, Ltd., were examined in the study. Each batch contained the original dried stevia leaf, the first water extract, and a final 95%  purity stevia leaf extract end product.
 
The samples were analyzed using ultra-violet high-performance liquid chromatography (UV-HPLC), and high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) to separate, identify and quantify the individual steviol glycoside molecules.  
 
“Our results show that the commercial powders of extracted steviol glycosides provided by PureCircle, Ltd., contain the same nine steviol glycosides analyzed as the dried stevia leaves and their hot water extracts. Our results also show a similar distribution pattern from the three very different stages of the process, clearly demonstrating that the nine steviol glycosides examined are not modified by the extraction or purification process,” said lead researcher Dr. Ursula Wölwer-Rieck, a food chemist in the Department of Nutritional and Food Sciences at the University of Bonn, Germany.  “These findings are significant because the natural authenticity of stevia sweetener has been questioned due to the purification process it undergoes. The fact that there is no change of the nine steviol glycosides in the provided samples from the original plant to extracted sweetener provides support for the natural authenticity of stevia sweeteners.”
 
Stevia is extracted and purified from the stevia plant into a powdered sweetener form. The extraction process involves steeping the dried leaves of the plant, like a tea, and then separating and purifying the best tasting sweet compounds, the steviol glycosides.  
 
High purity stevia leaf extract is approved in more than 150 countries, and over 200 studies support stevia’s science and safety. Since 2008, more than 10,000 products have launched globally with stevia. In 2016 alone, close to 3,000 products launched globally with stevia, with the beverage category growing by 20% and the food category growing by 9%.
 
“Given the growing global concerns about obesity and diabetes, as well as the new U.S. labeling regulations which require ‘Added Sugars’ to be listed on food labels in the near future, stevia is poised to help food and beverage companies reduce sugar and calories in their products,” said Dr. Priscilla Samuel, director of the Global Stevia Institute. “Consumers’ desire for a natural-origin, plant-based, zero calorie sweetener and ‘clean’ labels have contributed to the growth of stevia.  The research of the university of Bonn clearly supports the naturality of the steviol glycosides tested.”