2017 Science of Ingredients: Healthco
Stevia FSE: Enzyme-modified Stevia for a Superior Aftertaste Profile
Over the last several years, stevia (Stevia rebaudiana Bertoni) leaf extract has become a popular non-caloric sweetener alternative. Several types of stevia ingredients described as whole leaf powders, as well as standardized single-compound extracts obtained GRAS (generally recognized as safe) status and are now used in food products. The types of food items utilizing stevia range from baked goods and cereals to yogurt and beverages. However, formulating with this popular ingredient often presents a challenge due to the inherent bitterness of steviol glycosides, the class of compounds responsible for the distinctive organoleptic profile of stevia extracts. Stevia FSE, an innovative enzyme-modified steviol glycosides food ingredient, has been created with this problem in mind.
The advantage of Stevia FSE, also known as Better Stevia, is that it significantly reduces lingering bitter aftertaste of conventional stevia-containing food recipes. The process of producing Stevia FSE starts with high-quality whole leaf, subject to the extraction process where the only solvent used is food-grade ethanol. Next, the stevia extract undergoes the step of controlled enzymatic glycosylation. During this phase, steviol glycosides are “extended” to incorporate additional sugar-type molecules. Next, the material containing glycosylated steviol glycosides is filtered and spray dried to produce a fine powder.
The chemical structure of the enzyme-modified steviol glycosides in Stevia FSE has been thoroughly studied. For example, rebaudioside A (Reb A), the primary steviol glycoside found in stevia, contains four glucose units (attached to two different carbon atoms). The research demonstrated that the enzymatic glycosylation treatment augments this compound to have one to three additional glucose units, thus creating mono-, di- and tri-glycosyl Reb A found exclusively in Stevia FSE.1-3 This augmentation is believed to be responsible for the modification of the organoleptic profile.
Overall sweetness intensity of Stevia FSE relative to sucrose has been evaluated in volunteers using a set of blind-labeled samples. In aqueous solution, 0.055 g of Stevia FSE was shown to exhibit the same level of sweetness as 6 g of sucrose, which indicates that at the given concentration, it is about 100 times sweeter than sucrose.4 Metabolism of Stevia FSE has also been studied in detail.5 The research shows that in the body, enzymatically modified steviol glycosides are hydrolyzed to steviol by intestinal microflora through the same mechanism responsible for metabolism of non-enzymatically treated stevia.6 Following hydrolysis, steviol from Stevia FSE can be absorbed and then excreted in urine and bile as a glucuronide, or it is deconjugated and excreted with feces.7 Stevia FSE has an excellent safety profile and is established as GRAS.4
It has been well recognized that the taste profile of individual steviol glycosides depends on the number of glucose units attached to steviol. For example, Reb A, a tetraglycoside, has been shown to be less bitter than stevioside which contains only three glucose units.5 By utilizing controlled enzymatic process and lengthening the glucose chain of steviol glycosides, the bitter aftertaste in Stevia FSE is reduced even further. It is also worth mentioning that the glucose chains in the native steviol glycosides are in the form of β-glycosides, whereas the controlled enzymatic glycosylation adds α-glycosides to its structure. It has been suggested that the addition of different glucose stereoisomers might have significant impact on the properties of steviol glycosides, including attaining a more favorable overall taste and reducing the bitter lingering effect often attributed to conventional stevia extracts. From a practical prospective, Stevia FSE makes it easier to create more desirable, more palatable and ultimately more consumer-friendly food recipes.
1 Waszkuc T, Berkman, S., Emmel, K., Mohammed, F. High Performance Liquid Chromatography (HPLC) Characterization of the Enzymatic Glycosylation of Stevia rebaudiana: A Comparison of Enzyme Treated and Non-Enzyme Treated Stevia Extracts. Poster presented at the 38th Great Lakes Regional ACS Meeting (May 13-16), Lincolnshire, Il.2009.
2 Emmel K, Waszkuc, T., Kraemer-Berkman, S., Szczesniewski, A., D’Antonio, S. High-Resolution TOF LC/MS Characterization of the Enzymatic GLycosylation of Stevia rebaudiana: A Comparison of Natural and Enzyme-Treated Stevia Extracts Poster presented at the 57th ASMS Conference on Mass Spectrometry and Allied Topics (May 31-June 4), Philadelphia, PA.; 2009.
3 Waszkuc T, Berkman, S., Emmel, K., Jordan, S., Mohammed, F. . High Performance Thin Layer Chromatography (HPTLC) Characterization of the Enzymatic Glycosylation of Stevia rebaudiana: A Comparison of Enzyme Treated and Non-Enzyme Treated Stevia Poster presented at the 2009 AOAC Int. Annual Meeting (September 13-16), Philadelphia, PA.2009.
4 FDA. Agency Response Letter GRAS Notice No. GRN 000337. 2011; www.fda.gov/food/foodingredientspackaging/generallyrecognizedassafegras/graslistings/ucm262289.htm. Accessed Feb 19, 2013.
5 NOW Foods U. GRAS Assessment. Glycosylated Enzyme Treated Stevia. 2009.
6 Koyama E, Kitazawa K, Ohori Y, et al. In vitro metabolism of the glycosidic sweeteners, stevia mixture and enzymatically modified stevia in human intestinal microflora. Food Chem Toxicol. Mar 2003;41(3):359-374.
7 Wheeler A, Boileau AC, Winkler PC, et al. Pharmacokinetics of rebaudioside A and stevioside after single oral doses in healthy men. Food Chem Toxicol. Jul 2008;46 Suppl 7:S54-60.