an effect remaining until the taste buds perceive a neutral pH. Sweeteners are perceived by the human sweet taste receptor, hT1R2-hT1R3, which belongs to G protein-coupled receptors, modified by the two histidine residues (i.e. His30 and His60) which participate in the taste-modifying behavior. One site maintains the attachment of the protein to the membranes while the other (with attached xylose or arabinose) activates the sweet receptor membrane in acid solutions. As a sweetener As miraculin is a readily soluble protein and relatively heat stable, it is a potential sweetener in acidic food (e.g. soft drinks). While attempts to express it in yeast and tobacco plants have failed, researchers have succeeded in preparing genetically modified E. coli bacteria, lettuce and tomatoes that express miraculin. The scientists' crops resulted in 40 micrograms of miraculin per gram of lettuce leaves, with two grams of lettuce leaves producing roughly the same amount of miraculin as in one miracle fruit berry. The use of miraculin as a food additive was forbidden in 1974 by the United States Food and Drug Administration, in circumstances that have been interpreted as suggesting influence by competing commercial interests. Since 2011, The FDA has imposed a ban on importing Synsepalum dulcificum (specifying 'miraculin') from its origin in Taiwan, declaring it as an "illegal undeclared sweetener". Although this ban does not apply to fresh and freeze-dried miracle fruit, the fresh or normally-frozen berry deteriorates rapidly. The ban also does not apply to sale as a dietary supplement. There is informed opinion that the FDA ban could be overturned given sufficient funding for the required safety studies. Miraculin has a novel food status in the European Union. It is approved in Japan as a safe food additive, according to the List of Existing Food Additives published by the Ministry of Health and Welfare (published by JETRO). See also Brazzein Curculin Monellin Thaumatin Pentadin Cynarin Stevia References Taste modifiers Sugar substitutes Food science Biomolecules Chemopreventive agents