Presentation Transcript

1. The Sweet Alternative Stevia rebaudianaBertoni Chris Stothart

2. Stevia rebaudiana Outline • Overview • Historical Perspective • Botany • Ethnobotany • Chemistry • Extraction & Commercial Uses • Nutrition • Regulation • Controversies • References

3. Stevia rebaudiana Overview • Common names include: stevia, sweet leaf, sweet herb of Paraguay, honey leaf, & sugar leaf • Increasing popularity of artificial sweeteners over the past 20 years • Demand for “natural” & “healthier” alternatives • Perfect social, political, & economic climate • Widespread use as a non-nutritive sweetener due to sweet leaves • Much debate over its use & health implications

4. Stevia rebaudiana Historical Perspective • Used extensively by native cultures of South America for centuries • First introduced to Europe by Spanish conquistadores in 16th century • Reintroduced in early 20th century to scientific community by Italian-Swiss botanist Dr. Moisés S. Bertoni • 1905 – Bertoni classified & described stevia

5. Stevia rebaudiana Historical Perspective cont. • Since 1905 – Stevia has been widely studied • Throughout 20th century sweet compounds in leaves have been isolated, purified, patented, & used in commercial products • 1970s – Japan began using stevia in replace of artificial sweeteners & sugar • Largest consumers: Japan, South Korea, Brazil, & South America

6. Stevia rebaudiana Botany Tropical perennial & herbaceous shrub Native to Central & South America Member of Asteraceae (Sunflower Family) Grows 65-80 cm tall Typically found in semi-dry mountainous environments & grasslands Prefers well-drained non-saline soil with pH 6.5-7.5

7. Stevia rebaudiana Botany cont. Simple, opposite green sessile leaves Stem, branches, & leaves are all green & are covered with short, fine whitish hairs All green parts taste sweet Inflorescences are tiny white & purple disk florets Develop achene fruits

8. Stevia rebaudiana Commercialcultivation Paraguay, Brazil, Japan, China, Korea, Mexico, USA, Indonesia, Tanzania, & Canada

9. Stevia rebaudiana Ethnobotany • Guarani natives (Paraguay) credited with first using the dried leaves to sweeten yerba mate (Ilex paraguariensis) & chewed the fresh leaves • Natives used orally delivered concoctions as a contraceptive, to manage diabetes, and to treat stomach aches • Caáhê-é or Kaàheè, which in Guaraní, a local dialect, translates into “sweet herb” • Lack of cultural & written records of stevia

10. Stevia rebaudiana Ethnobotanycont. Figure 4: Paraguayans harvest stevia. 3 explanations for limited historical record 1. Sweet-tasting properties were known since the beginning of time, but kept a secret 2. Natives shared plant with Spaniards, but the knowledge was disregarded or overlooked 3. Stevia’s potential as a sweetener was not discovered by natives until only a short time before European contact

11. Stevia rebaudiana Chemistry • Active compounds: group of diterpene (steviol) glycosides • dulcoside A, rebaudiosides A-E , steviolbioside, & stevioside • Rebaudioside A (3.8%) and stevioside (9.1%) are the sweetest, most abundant, & most important commercially • Highest yield of these compounds in leaves just before the plant begins to flower,

12. Stevia rebaudiana Chemical structures Chemical structure of stevioside (left) and rebaudioside A (right)

13. Stevia rebaudiana Extraction & Commercial Uses • Processing of dried leaves from Stevia produces a powdery white substance (stevioside), which is three hundred times sweeter, by weight, than sucrose derived from sugar cane • Water extraction process followed by crystallization techniques to isolate the steviol glycosides • NRC has patent on nanofiltration techniques commercially available stevia products: stevioside and rebaudioside A include Truvia, Fructevia, Krisda, & PureVia.

14. Stevia rebaudiana Commercial products

15. Stevia rebaudiana Nutrition • The dried leaves are 30 to 45 times as sweet as sucrose • Non-nutritive, three hundred times sweeter than sugar, heat stable, non-fermentable, as well as an anti-plaque and anti-carie • More studies must be conducted on bulking agents to make it easy to replace it for sugar

16. Stevia rebaudiana Regulation • Traditionally, North America & EU have only permitted use of highly purified extracts for sale in health food stores & pharmacies • Leaves classified as a dietary supplement, but not as a sweetener (Health Canada 2011) • FDA & Health Canada has approved use of stevia derivatives as a sweetener in some products (FDA 2011; Health Canada 2011) • Marketed as medicinal, non-medicinal ingredients & for personal culinary use

17. Stevia rebaudiana Controversies • Few conclusive results verifying negative health claims • Investigated effect of stevia on energy & carbohydrate metabolism, on the cardiovascular & renal systems, & reproduction • Diabetes mellitus: helps with proper blood glucose control, as antihyperglycemic by stimulating the release of insulin, & to help prevent insulin intolerance in diabetic patients • Need for further clinical trials to ensure safety of stevia for widespread human consumption

18. Stevia rebaudiana Questions

19. Stevia rebaudiana References Goyal, S. K., Samsher, and Goyal, R.K. 2010. Stevia (Stevia rebaudiana) a bio-sweetener: a review. Intl. J. Food Sci. and Nutr. 61(1): 1-10. Guens, J. C. 2003. Stevioside. Phytochemistry. 64(5): 913-921. Health Canada. 2011. Frequently Asked Questions "FAQs" on Stevia [online]. Available from http://www.hc-sc.gc.ca/. [accessed 10 March 20111]. Huxtable, R. J. 2002. Pharmacology and toxicology of stevioside, rebaudioside A, and steviol. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp. 160-177. Jeppesen, P. B., Gregersen, S., Rolfsen, S. E. D., Jepsen, M., Colombo, M., Agger, A., Xiaso, J., Kruh, M., and Hermansen K. 2003. Antihyperglycemic and blood pressure-reducing effects of stevioside in the diabetic Goto-Kakizaki rat. Metabolism. 52: 372-378. Kinghorn, A. D. 2002. Overview. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp. 1-17. Krisda Canada. Product Information [online]. Available from http://www.krisda.ca/. [accessed 10 March 2011]. Lewis, W. H. 1992. Early uses of Stevia rebaudiana (Asteraceae) leaves as a sweetener in Paraguay. Econ. Bot. 46: 336-340. Madan, S., Ahmad, S., Singh, G. N., Kohli, K., Kumar, Y., Singh, R., and Gard, M. 2010. Steviarebaudiana (Bert.) Bertoni – A Review. Ind. J. Nat. Prod. 1(3): 267-286. Rolfes, S. R., Pinna, K., and Whitney, E. 2009. Understanding Normal and Clinical Nutrition (8th ed.). Wadsworth, Cengage Learning, CA, USA. pp. 136. Samuelsson, G. 1992. Drugs of Natural origin. Swedish Pharmaceutical Press, Origin Stockholm Sweden. Shi Qiu, Z., Ashwani, K., and Oleh, K. 2000. Membrane-based separation scheme for processing sweeteners from stevia leaves. Food Res. Int. 33: 617-620. Soejartoa, D. D. 2002. Botany of Stevia and Stevia rebaudiana. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp. 18-39. Soejartob, D. D. 2002. Ethnobotany of Stevia and Stevia rebaudiana. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp. 40-67. Strauss, S. 1995. The perfect sweetner? Technol. Rev. 98: 18-20. Sumida, T. 1980. Studies on Stevia rebaudianaBertoni M, introduced from Brazil as a new sweetness resource in Japan. J. Cent. Agric. Exp. Stn.31: 1-71. The National Geographic Society. 2008. Edible: An Illustrated Guide to the World’s Foods Plants. Global Book Publishing, Washington, DC. pp. 333. United States Food and Drug Administration (FDA). 2011. What refined Stevia preparations have been approved by FDA to be used as a sweetener? [online]. Available from http://www.fda.gov. [accessed 10 March 2011]. United States Patent and Trademark Office. 1998. United States Patent: 5,972,120 Extraction of sweet compounds from Stevia rebaudianaBertoni [online]. Available from http://patft.uspto.gov/. [accessed 10 March, 2011] Wheeler, A., Boileau, A. C., Winkler, P. C., Compton, J. C., Prakash, I., Jiang, X., and Mandarino, D. A. 2008. Pharmacokinetics of rebaudioside A and stevioside after single oral doses in healthy men. Food Chem. Toxi. 46: 54-60.