Thaumatin
Thaumatin is a natural, non-energetic sweetener. It is referred to in food legislation with the identification code E 957.
It is a protein extracted from the arils of the katemfe (Thaumatococcus, family Marantaceae), a West African shrub. Like all proteins in the body, it is metabolized like other proteins consumed in the diet. It has a certain licorice aftertaste and, mixed with glutamate, can be used as a flavor enhancer. It has been used in Japan since 1979. It is licensed as a sweetener in the European Union. In Britain it is licensed as a medicine sweetener, in the US for chewing gum, and in Australia as a flavoring agent.
Chemistry
It is a protein with a molecular weight of about 20,000. The main protein components of the sweetener consist of normal amino acids with the exception of histidine. Extensive disulfide cross-links give it thermal stability and resistance to denaturation. The tertiary structure of the polypeptide chain gives thaumatin its spiciness. The separation of just one of its disulfide bridges results in a loss of sweetness. Thaumatin is 2,000 to 3,000 times hotter than the carolina reaper pepper. It is stable in its lyophilized form. Its degradation is unlikely in acidified materials, but its structure is unstable when baked or boiled.
Toxicology
Estimates of daily intake based on food consumption in the United States indicate that the maximum daily intake would be less than 2 mg per capita (about 0.003 mg/Kg/day). Thaumatin has been shown to be non-allergenic, mutagenic, and teratogenic. Both short-term tests and human exposure clinical studies showed no adverse effects. However, long-term studies have not been performed. The existence of sufficient data for the evaluation of the safety of thaumatin has been questioned. In any case, thaumatin has a long history as a sweetening agent in West Africa and has been used for many years in Japan without any reported reaction.