In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. A glucoside is a glycoside that is derived from glucose.
Steviol is the central core of all steviol glycosides, or called the aglycone part (where R1 = OH, and R2 = H).
Glucose or glucose-combinations are bound to the R1 and R2 ends of the aglycone to form the different steviol glycosides.
1) Carakostas, M., Prakash, I., Kinghorn, A. D., Wu, C. D., and Soejarto, D. D. 2012. Steviol Glycosides. In Lyn O’Brien Nabors (2012). Alternative Sweeteners. 4th ed. CRC Press. 548p. ISBN 978-1-4398-4615-5.
2) Brandle, J. E., and Telmer, P. G. 2007. Steviol glycoside biosynthesis. Phytochemistry 68:1855–1863.
Steviol glycosides are molecules that contain two parts, aglycone and glucose components. When a glycoside meets the taste receptors in the tongue, the different receptors react to aglycone and glucose components, respectively. Sweet receptors react to glucose components and give the sweet taste. While bitter receptors react to the aglycone and give the bitter taste.
Stevioside and rebaudioside A exhibit clean sweetness at low sweetness potency (SE) levels, but have other negative taste attributes (e.g., bitterness and black licorice) at higher SE levels. Stevioside exhibits much more bitterness than rebaudioside A.
Sweetness Temporal Profile
Sweetness temporal profiles demonstrate changes in perception of sweetness over time. Every sweetener exhibits a characteristic Appearance Time (AT) and Extinction Time (ET). All high-potency sweeteners, in contrast to carbohydrate sweeteners, display prolonged ETs. The AT maximum was shortest for sucrose, slightly longer for aspartame and longest for rebaudioside A. The ET was longest for rebaudioside A, followed by aspartame and then sucrose, with the ET of rebaudioside A being significantly longer than sucrose.