Taste relationship

For more information including theories of structure-taste relationships see the symposium Sweeteners and Sweetness Theory m the August 99S ssue oi the Journal of Chemical Education pp 671-683... 

Aspartame (L-aspartyl-L-phenylalanine methyl ester [22839-47-0]) is about 200 times sweeter than sucrose. The Acceptable Daily Intake (ADI) has been estabUshed by JECFA as 40 mg/kg/day. Stmcture-taste relationship of peptides has been reviewed (223). Demand for L-phenylalanine and L-aspartic acid as the raw materials for the synthesis of aspartame has been increasing, d-Alanine is one component of a sweetener "Ahtame" (224). 

For more information, including theories of structure-taste relationships, see the symposium "Sweeteners and Sweetness Theory" in the August, 1995 issue of the Journal of Chemical Education, pp. 671-683. 

The evaluation of sweet compounds by taste panels is crucial to the development of worthwhile structure-taste relationships. Many structure-taste studies have employed dubious, taste-panel techniques. Therefore, a critical examination of structure-taste data in the light of this observation is relevant, as are recommendations for a consistent approach in utilizing taste techniques. ... 

Much of our present day knowledge of sweetness intensity, both at the threshold level, where taste begins, and above the threshold level, derives from the application of psychophysical techniques. It is now evident that the psychophysical procedure used measure separate aspects of sweetness perception. Hedonic responses cannot be predicted from intensity of discrimination data, and vice versa. The taste-panel evaluation of sweetness is of fundamental importance in the development of worthwhile structure-taste relationships. Therefore, it is vital that the appropriate psychophysical method and experimental procedure be adopted for a particular objective of investigation. Otherwise, false conclusions, or improper inferences, or both, result. This situation results from the failure to recognize that individual tests measure separate parameters of sensory behavior. It is not uncommon that the advocates of a specific method or procedure seldom... 

The influence of structural features of benzodioxepine and benzodithiepine derivatives on rat brain benzodiazepine receptors has been studied <1996MSR589>. A group at Givaudan has synthesized and studied the conception, characterization, and correlation of new marine odorants based on the benzo[A][l,4]dioxepinone system <2003EJO3735>. 1,4-Dithiapane was among a data set of 101 hetero sulfamate sodium salts that was tested as potential sweeteners in a structure-taste relationship study <2000J(P2)1369>. 

R. H. Mazur, J. M. Schlatter, and A. H. Goldkamp, Structure-taste relationships of some dipeptides,... 

Sweet and Bitter Compounds Structure and Taste Relationship... 

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. 

After the finding of a sweet taste in L-Asp-L-Phe-OMe (aspartame) by Mazur et at. (6), a number of aspartyl dipeptide esters were synthesized by several groups in order to deduce structure-taste relationships, and to obtain potent sweet peptides. In the case of the peptides, the configuration and the conformation of the molecule are important in connection with the space-filling properties. The preferred conformations of amino acids can be shown by application of the extended Hiickel theory calculation. However, projection of reasonable conformations for di- and tripeptide molecules is not easily accomplished. 

In the course of investigations of aspartyl dipeptide esters, we had to draw their chemical structures in a unified formula. In an attempt to find a convenient method for predicting the sweettasting property of new peptides and, in particular, to elucidate more definite structure-taste relationships for aspartyl dipeptide esters, we previously applied the Fischer projection technique in drawing sweet molecules in a unified formula 04). 

The structure-taste relationships will be discussed in detail. Dipeptide esters are closely related to amino acids in chemical structure and properties. Hence, we selected amino acids as the standard to which sweet peptides were related. The structural features of sweet-tasting amino acids have been best explained by Kaneko (12) as shown in Figure 2, in which an amino acid will taste sweet when R2 is H, CH3 or C2H5, whereas the size of Ri is not restricted if the amino acid is soluble in water. 

Spillane, W.J., McGlinchey, G, Muricheartaigh, I.O. and Benson, G.A. (1983). Structure-Activity Studies on Sulfamate Sweeteners. 3. Structure-Taste Relationships for Heterosulfamates. J.Pharm.Sci., 72, 934. 

Many sulfamic acid derivatives are sweet and much work has been carried out on structure-taste relationships. For example, research showed that sodium exo-2-norbornylsulfamate (89) was some five times sweeter than sodium cyclamate (88), although the corresponding endo-isomer (90) was tasteless (Figure 3). 

The sulfur derivative (87) is 1000 times as sweet as sugar and without the bitter after-taste of saccharin however, it was discovered that N-alkylation of (87) removed the sweetness. On the other hand, in the saccharins (88a)-(88e) containing substituents in the 4-position and 6-position, sweetness was retained after N-alkylation. Many sulfamic acid derivatives are sweet, and there have been numerous studies of structure-taste relationships which have highlighted the importance of molecular shape and stereochemistry (see Chapter 9, p. 162). Two sulfamates which are commercial, non-nutritive sweeteners are cyclamate (85) and acesulfame potassium (86) (Figure 11). Cyclamate (85) is manufactured by refluixing cyclohexylamine either with triethylamine-sulfur trioxide in dichloromethane or with sulfamic acid (see Chapter 9, p. 162). 

Spadaccini R, Trabucco F, Saviano G, Picone D, Crescenzi O, Tancredi T, Temussi PA (2003) The mechanism of interaction of sweet proteins with the T1R2-T1R3 receptor evidence from the solution structure of G16A-MNEI. J Mol Biol 328 683-692 Spillane WJ, Kelly DP, Curran PJ, Feeney BG (2006) Structure-taste relationships for disubsti-tuted phenylsulfamate tastants using classification and regression tree (CART) analysis. J Agric Food Chem 54 5996-6004... 

Acton, E.M., and Stone, H. (1976). Potential new artificial sweetener from study of structure-taste relationships. Science 193,584—586. 

TABLE 41.3 Empirical and Qualitative Structure-Taste Relationships ... 

Kelly, D.P., Spdlane, W.J. and Newell, J. (2005) Development of structure-taste relationships for monosubstituted phenylsulfamate sweeteners... 

A semi-quantitative structure-taste relationship has been derived97 and extended98 for carbosulphamates using Corey-Pauling-Koltun (CPK) space-filling models for measurements of parameters. Structure-taste relationships for heterosulphamates were developed... 

As in the previous section much of the work here has been motivated by the desire to establish new structure-taste relationships for sweeteners. 

The heterocyclic sulphamate 86 has been synthesized96. The sulphamates 87-92 were synthesized to help probe and extend the existing taste relationships in this field98. The mono- and di- sodium salts of antipyrine sulphamate (93) have been prepared by the reduction of nitrosopyrine with a sulphite-bisulphite mixture112. 

Table 39.2 Empirical and qualitative structure-taste relationships ...

Mazur, R.H., Goldkamp, A.H., James, P.A., Schlatter, J.M. Structure-taste relationships of aspartic acid amides. J. Med. Chem. 13,1217 (1970)... 

BeUtz, H.-D., Chen, W., Jugel H., Treleano, R., Wieser, H., Gasteiger, J., Marsili, M. Sweet and bitter compounds Structure and taste relationship, in Food taste chemistry (Ed. Boudreau, J.C.), ACS Symposium Series 115, p. 93, American Chemical Society Washington, D.C. 1979... 

Many other sulfamates are sweet and considerable studies have been made on structure-taste relationships in this group of chemicals (Chapter 6, ref 33). 

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