Could It Taste as Sweet?
New compounds that realign perceptions of sweetness and bitterness are nearing the marketplace.
As basic research into taste perception continues, scientists are exploring practical uses for expanding knowledge in the field. In two papers in the March 2010 Proceedings of the National Academy of Sciences, researchers from Senomyx—founded in 1998 by Charles Zuker, a neuroscientist at Columbia University who was then at the University of California, San Diego; future Nobel Laureate Roger Y. Tsien, also at UCSD; and Stanford University neurobiologist Lubert Stryer—described how they developed two sweet taste enhancers.
The Senomyx scientists focused on the extracellular extension of a sweet receptor protein that functions like a Venus flytrap with a hinge mechanism. When a sucrose molecule binds to the receptor, the hinge closes around the sucrose and activates the receptor, which triggers a nerve impulse to send a signal of sweetness to the brain.
But sucrose binds to the receptor rather halfheartedly, and the signal to the brain is weak, says Donald S. Karanewsky, Senomyx’s chief scientific officer. So Senomyx designed a molecule that enhances the affinity of the sucrose molecule to the receptor. That sends a stronger sweet signal to the brain; as a result, half as much sucrose tastes just as sweet. The company applied the same approach to make an enhancer of sucralose, the artificial sweetener in Splenda, that reduces the amount of sucralose needed by 75% and softens any aftertaste.
At Givaudan Flavors in Cincinnati, researchers have produced a bitter taste blocker to reduce the aftertaste some people experience with the artificial sweetener saccharin. Givaudan reported at a March 2011 meeting of the American Chemical Society that its scientists had found a compound that prevented saccharin from activating a bitter taste receptor. After vetting it for safety, they gave it to human taste testers, then tweaked the molecule to make it 10 times more potent.
These and other flavor companies are working on additional compounds. Some enhancers and blockers have already made their way into products on grocery shelves. Many others are nearing production.