From "The search for sweet", Burkhard Bilger,
The New Yorker 22 May 2006:
Taste potentiators, as they're called, are not entirely new to the food industry. The ingredient list on a can of soup or a hunk of processed cheese sometimes includes a substance called IMP, a few entries below MSG, or sodium glutamate. MSG is to umami what sugar is to sweet: the taste [of protein] in its purest, most familiar form. IMP's singular virtue is its synergy with MSG. Like the sweet receptor, the umami receptor has multiple binding sites. IMP attaches to one spot, MSG to another; together, they fit so snugly that their effect is multiplied. Add a little IMP to a soup with MSG in it, and the umami taste will increase roughly tenfold. "It's like a hearing aid," Zoller told me. It turns up the volume.
Senomyx has found four new umami potentiators in the course of its chemical trawling, all of them more effective than IMP, all recently declared safe by the FDA. (The first products containing them should appear later this year. The company's two sweet potentiators aren't quite as far along. The best one is known as Substance 951. If you add only a few parts per million of it to a soda, you can take out forty percent of the sugar and the soda will taste as sweet. But Senomyx is still working on making it stronger and on improving or eliminating its taste. (I wasn't allowed to try it.) Zoller says that the compound should be on the market by next year, but most consumers won't be aware of it. Like the new umami potentiators, Substance 951 will be used in such tiny quantities that it won1t have to be listed on labels. Instead, it will join all the other "natural and artificial flavors" that float through our foods, ignored by all but the most obsessive ingredient-watchers, and quietly do the work that sugar once did.
The article seems to be unavailable online, but it's worth tracking down just for the description of the testing:
... artificial taste buds: human cells, with a single taste receptor, engineered with a fluorescent dye that lights up only when the receptor is triggered. The cells are placed in clear plastic trays divided into three hundred and eighty-four wells ...
Another food diary today, much better than this one: OrangeClouds115's
VMD: Roundup Ready Edition. Long, but worth the read. Print it if that eases your eyeballs.