New research conducted at the University of Bonn in Germany found that the sweet, stevia plant molecules remain unchanged throughout the stages of processing. The study supports stevia’s naturality and found all nine of the steviol glycoside molecules required by the specifications set by the Joint Expert Committee on Food Additives (JECFA), a committee jointly administered by the and Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO), were present and unchanged in the dried stevia leaf, through the commercial extraction and purification process and in the final stevia leaf extract product.
 
This research looked at three separate batches of stevia leaf that went through commercial production to final product, the 95% purity stevia leaf extract. The study samples were provided by PureCircle and each of the three, commercial batches included the dried stevia leaf, the first water extract and the final product from each of the three corresponding leaf samples. The research found that the stevia leaf extract end products were of 95% purity, which is required by JECFA. This is the first time a study has examined steviol glycosides from multiple commercial stevia leaf samples through different stages in the extraction and purification process, starting with the leaf and ending with the stevia sweetener end product.
 
This study used well-known analytical techniques such as high-performance liquid chromatography (HPLC) in combination with C18 and/or hydrophilic interaction liquid chromatography (HILIC) columns to separate, identify and quantify the individual steviol glycoside molecules.
 
“Finding the same nine steviol glycoside molecules unchanged in the stevia leaf, the water extract and in the final product confirms that the commercial extraction and purification process of high purity stevia leaf extract does not alter the sweet steviol glycoside molecules in the leaf,” said Dr. Ursula Wölwer-Rieck, the scientist at the University of Bonn, Germany who conducted the stevia research. “Showing that it is unchanged is important in this whole naturality debate because there are people who still call into question the naturality of high purity stevia leaf extract.”  
 
Dr. Wölwer-Rieck, a well-known stevia expert and a tenured academic Councilor in the Department of Nutrition and Food Sciences at the University of Bonn. Dr. Wölwer-Rieck is also a board member of the European Stevia Association (EUSTAS) and a member of the Advisory Board of the Global Stevia Institute. As a food chemist her academic research has focused on steviol glycosides and she has published papers on their analysis and stability in food.  
 
“For us, this study supports something that we have believed all along,” said Dr. Priscilla Samuel, director of the Global Stevia Institute. “That, the sweet molecules of high purity stevia leaf sweetener are the same sweet molecules in the leaf and have the ability to completely change the way we sweeten foods and beverages. So many people today want that zero-calorie sweetness from a natural source and this research supports its naturality from the leaves through the finished product.”
 
These research findings will be presented this weekend during the 15^th International Conference on Food Processing & Technology by Dr. Wölwer-Rieck.