Sweet-tasting compounds

Fig. 1. Sweet-tasting compounds of various chemical classes and their common (ah-b) unit, (a) P-D-fmctose (b) saccharin (c) chloroform (d) unsaturated...

Oertly and Myers Auxogluc and Glucophore Components of Sweet-tasting Compounds... 

By identifying the most acidic proton in a number of sweet-tasting compounds, Shallenberger and Acree proposed possible locations for the AH,B systems of these compounds (see Fig. 5). 

Stevioside is the most abundant sweet-tasting compound in the leaves. Bridel and Lavielle isolated the crystalline glycoside, stevioside from an alcoholic extract of S. rebaudiana and found it to be 300 times sweeter than... 

The current accepted theory suggests that a bitter compound and a sweet compound bind independently at specitic receptors. This situation will be referred to as "independent" in this report. The data to follow will demonstrate that a bitter compound and a sweet compound bind at the same receptor in a competitive manner. Therefore, this situation will be referred to as "competitive" in this report. Which theory was the functioning mechanism of taste reception should be determinable when one measured the taste intensities of mixed solutions of bitter and sweet tasting compounds. In this experiment the mechanism could be predicted to elicit a considerable difference in taste intensity and response that was varying based on the final concentration of each component. The "independent" receptor mechanism would be expected to yield data in which the intensities of bitter and sweet would be unaffected by mixing the two tastes, no matter what the concentration. On the other hand, with the "competitive" receptor mechanism one would expect both flavors to become altered, i.e., one stronger and the other weaker, as component concentrations varied the latter would occur because of competition of the substances for the same site. 

It is known that sweet-tasting compounds are quite common and their chemical structures vary widely. In order to establish a structure-taste relationship, a large number of compounds have been tested, and several molecular theories of sweet taste have been proposed by different groups. At present, the phenomenon of sweet taste seems best explained by the tripartite functioning of the postulated AH, B (proton donor-acceptor) system and hydro-phobic site X (1, 2, J3, 4 5). Sweet-tasting compounds possess the AH-B-X system in the molecules, and the receptor site seems to be also a trifunctional unit similar to the AH-B-X system of the sweet compounds. Sweet taste results from interaction between the receptor site and the sweet unit of the compounds. Space-filling properties are also important as well as the charge and hydro-phobic properties. The hydrophile-hydrophobe balance in a molecule seems to be another important factor. 

Many investigators have attempted to relate the chemical structure of sweet tasting compounds to the taste effect, and a series of theories have been proposed (Shallenberger 1971). Shallenbeiger and Acree (1967, 1969) pro-... 

In this section, the presently known highly sweet substances of natural origin are described. Sweet-tasting compounds are listed in Table 1, with information published subsequent to an earlier chapter [16] then discussed in more detail. The structures of the compounds mentioned will be interspersed in the text, with the following abbreviations used to designate the sugar units of glycosides api = D-apiofuranosyl ara = L-... 

In order to analyze for sweet taste compounds in beef bouillon, the low molecular weight fraction was further separated by gel permeation... 

In order to study the influence of the pH value on the sweetness enhancing effect of the novel Maillard reaction product, binary mixtures of the tasteless alapyridaine and the sweet tasting compounds glucose, saccharose, or L-alanine were sensorially evaluated in a triangle test using water with pH 5.0, 7.0 and 9.0, and the sweet detection thresholds determined were compared to the threshold concentrations of aqueous solutions containing the sweet tastants alone (Table I). 

Table I. Effect of Alapyridaine on the Detection Thresholds of Sweet Tasting Compounds...

The sweet-tasting compounds from Abrus fruticulosus and A. precatorius (Fabaceae) also are a mixture of triterpene glycosides related to cycloartenol (Choi et al., 1989 Fullas et al., 1990). Abrusosides A-D (19-22) are 30-100 times sweeter than a 2% solution of sucrose. 

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