Monellin

Monellin is a sweet-tasting protein discovered in 1969 in the fruit of the serendipity berry, Dioscoreophyllum cumminsii, a shrub native to West Africa; it was named in 1972 after the Monell Chemical Senses Center in Philadelphia, where it was isolated and characterized. It is remarkably potent, measuring roughly eight hundred to two thousand times sweeter than sucrose depending on the concentration compared, though its sweetness has a slow onset and a lingering aftertaste, its flavor is pH dependent, and it is unstable at high temperatures, limiting its use in processed food. Monellin is also difficult to extract from its plant source, which is itself hard to cultivate commercially; it is not legally approved as a sweetener in the European Union or United States, though Japan recognizes it as an approved food additive.