Sweetness inducers

Enhancers and Inducers. A sweetness enhancer is defined as a compound that imparts no taste per se, but when combined with a sweetener in small quantities, increases sweetness intensity. A tme sweetness enhancer has yet to be found. However, a good sweetness inducer, miraculin [143403-94-5] or [125267-18-7] (124), is known. Miraculin is a glycoprotein found in the fmit (called Miracle Fmit) of a West African shmb, chardella dulcifica. By itself, miraculin imparts no sweetness. When activated in the mouth by acidic substances, however, a sucrose-like sweetness is perceived. Thus, sour lemon, lime, grapefmit, rhubarb, and strawberry taste sweet when combined with miraculin. The taste conversion effect can last an hour or longer. 

In 1974, a petition for affiimation of the GRAS status of miracle fmit was submitted by the Miralin Company, mainly based on the fact that miracle fmits have been consumed by humans since before 1958. In 1977, the petition was denied by the FDA. However, miraculin remains a research curiosity. Its stmcture was elucidated in 1989 (125). Another protein, curculin [151404-13-6] (126), has also been reported to exert a sweet-inducing activity similar to miraculin. 

Brouwer JN, van der Wei H, Francke A, Henning GJ, MiracuHn, the sweetness-inducing protein from miracle fruit. Nature 220 373—374, 1968. 

Besides the naturally occurring saccharides and polyols, there are a number of plant-derived highly sweet compounds, which are mostly terpenoids, flavonoids, and proteins [16-18]. Several of these sweet substances are used commercially as sucrose substitutes, as will be described in the next section. In addition, a number of plant substituents are known to mediate the sweet-taste response, either by inducing or inhibiting the perception of sweemess [19]. Thus far, all of the known natural product sweet-tasting substances and sweetness modifiers have been obtained from green plants [16-19]. In the remaining sections of this chapter, plant-derived sweet compounds with commercial use will be described, followed by a section on recent theories on the sweet taste phenomenon, and then individual descriptions of potent sweeteners, sweetness inducers, and sweetness inhibitors from plants will be presented in turn. The literature has been surveyed for this chapter until the end of 1999. 

Kurihara, Y. (1992). Characteristics of antisweet substances, sweet proteins, and sweetness-inducing proteins. Crit. Rev. Food Sci. Nutr. 32, 231-252. 

Several natural products are known to modify the sense of sweet taste. Such compounds can be either sweetness inhibitors or sweetness inducers/enhancers. A review of Suttisri et al., 1995 summarizes data on phytochemistry and biological activity of more than 40 triterpenoid sweetness inhibitors based on the oleanane and dammarane skeletons. These saponins were isolated from the leaves of Gymnema sylvestre, Zizyphus jujuba and Hovenia dulcis [224]. Recently, antisweet oleanane-type saponins were isolated from Stephanotis lutchuensis vm. japonic a [225]. 

A number of non-proteinaceous substances of plant origin are known that induce or inhibit the sensation of sweetness. Sweetness inducers and enhancers from plants include cynarin, chlorogenic acid, caffeic acid, and arabinogalactin (larch gum) (33). A synthetic compound, 2-(4-methoxyphenoxy)propanoic acid, which is also a constituent of roasted coffee beans, is currently on the market as a sweetness inhibitor (33). Several oleanane-type triterpene esters with sweetness-inhibitory activity occur in Gynmema sylvestre leaves (33,116,117), with dammarane-type saponins with similar effects having been reported recently from the leaves of Hovenia dulcis Thunb. (Rhamnaceae) (118) and Ziziphusjujuba Mill. (Rhamnaceae) (33,119,120). 

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