Sweetness inhibitors

In these cases, masking flavours can be used together with a rebalancing of the flavour profile to cover the changes in perception. The use of sweet inhibitors such as lactisol (6, Fig. 21.3) can help to reduce the lingering aftertaste in some cases. 

Dammarane glycosides Hooenia chick (Chinese raisin tree) Sweetness inhibitors... 

There are only a few sweetness inhibitors known. This article will focus on three sodium dodecyl sulfate (SDS), the gymnemic acids (GA) and the ziziphins (ZJ). Each of these substances has the ability to diminish or eliminate the ability to recognize sweetness. The intensity and duration of the effect varies with the inhibitor. 

The best-known sweetness inhibitor is sodium dodecyl sulfate (SDS), also known as sodium lauryl sulfate. This substance is a twelve carbon surfactant that is quite commonly used as a detergent in toothpaste. The observation is often made that after brushing one s teeth, the taste of orange juice is unusually bitter. This has been ascribed to the presence of SDS in the dentifrice (6 ). 

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. 

Table 2. Sweetness Inhibitors from Plants (continued)...

Subsequent to the isolation of the dammarane-type triterpenoid glycosides jujuboside B (112), hodulosides I-V (113-117), hovenoside I, and saponins C2, E, and H (122-125) as sweetness inhibitors from the leaves of Hovenia dulcis Thunb. var. tomentella Makino [139], hodulosides VII-X (118-121) were isolated as sweetness-inhibitory agents [140]. Hodulosides I (113) and II (114) have hovenolactone (151) as their aglycone which is the same compoimd as in saponins E (124) and H (125). Hodulosides Ill-V and VII-X (115-121) are based on two different danunarane-type aglycone structures, however [139,140]. The sweetness-inhibitory potencies of hodulosides are shown in Table 2. The sweetness-inhibitory potency of hoduloside X (121) was not determined [140]. 

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). 

At least 10 of jujube s saponins (e.g. ziziphin, jujubasaponins, and jujuboside B) are sweetness inhibitors that reduce the sensation of sweet taste (elevate the sweetness threshold) of glucose, fructose, aspartame, and other sweetening agents. No taste modifying effect was observed with bitter, salty, or sour flavors. 

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