KSU plant biochemical geneticist Raj Nagarajan describes the properties of Thaumatin, Monellin and Brazzein, all found in west African plants that are generally considered safe for consumption; each is a protein, and they are, respectively, 1,000x, 2000x, and 3000x sweeter than sugar.
Thaumatin and Monellin have been approved as sweeteners in Japan and for some purposes in the EU and US, while Brazzein awaits regulatory approval. They contain "negligible" calories, and no known negative metabolic effect — no experimental effects on blood sugar or body weight.
There are challenges to the large-scale use of these proteins. Monellin breaks down under high temperatures, making it unsuited to baking, for example — though Brazzein is very stable and promising, and can be expressed in GMO corn.
Scientists are just beginning to solve the mysteries of these sweet proteins and how they induce the sweetness on our tongues. All these studies promise to help us understand why we crave sugary substances and why some people want sugar more than others. Customer demand will lead to new types of foods that do not contain as much sugar and that would ultimately help people reduce their consumption of it. Therefore, sweet proteins might play a pivotal role both in food and taste research in the future. And since it has been shown that too much sugar is detrimental to one’s health, they might be a viable substitution for sugar in foods. But, you may say, we just learned about the existence of sweet proteins; how nice it will be to taste a brazzein- or monellin- supplemented diet ice cream. Yes, you are right—variety is the spice of life, and innovation to reduce the amount of sugar in food, while maintaining product integrity, is an absolute necessity for good health. You can have your cake and eat it too!