Aspartame sweet taste

Alitame (trade name Adame) is a water-soluble, crystalline powder of high sweetness potency (2000X, 10% sucrose solution sweetness equivalence). The sweet taste is clean, and the time—intensity profile is similar to that of aspartame. Because it is a stericaHy hindered amide rather than an ester, ahtame is expected to be more stable than aspartame. At pH 2 to 4, the half-life of aUtame in solution is reported to be twice that of aspartame. The main decomposition pathways (Fig. 6) include conversion to the unsweet P-aspartic isomer (17) and hydrolysis to aspartic acid and alanine amide (96). No cyclization to diketopiperazine or hydrolysis of the alanine amide bond has been reported. AUtame-sweetened beverages, particularly colas, that have a pH below 4.0 can develop an off-flavor which can be avoided or minimized by the addition of edetic acid (EDTA) [60-00-4] (97). 

Lactisole [13794-15-5] the sodium salt of racemic 2(4-methoxyphenoxy)propionic acid, is a sweet-taste inhibitor marketed by Domino Sugar. It was affirmed as a GRAS flavor (FEMA no. 3773). At a concentration of 100 to 150 ppm, lactisole strongly reduces or eliminates the sweet taste of a 10% sugar solution. This inhibition appears to be receptor-related because lactisole also inhibits the sweet taste of aspartame. The 5 -( —)-enantiomer [4276-74-8] (38), isolated from roasted coffee beans, is the active isomer the i -(+)-enantiomer is inert (127). 

During work on a series of aspartyl dipeptides containing ACC 71 (vide supra, Eq. (28), Sect. 4) at the carboxyl terminus, it was reported that dispartame Asp-ACC-OMe had a distinct sweet taste [302] and that the corresponding n-propyl ester had 250-300 times the sweetness of sucrose [303]. However, replacement of phenylalanine by 2,3-methanophenylalanine gave tasteless analogues of aspartame [293, 304], and some dimethyl-ACC 214 (methanovaline) and tri-methyl-ACC 215 aspartame analogues [Asp-(Me)n-ACC-OMe] have a bitter taste. These taste properties, which depend on the number and position of the methyl substituents, have been explained on the basis of topochemical models thus, a L-shaped conformation of the dipeptide is necessary for sweet taste, Eq. (86) [3051. 

Sweet Taste. The mechanism of sweetness perception has been extensively studied because of its commercial importance. Many substances that vary in chemical structure have been discovered which are similar to the taste of sucrose. Commercial sweeteners include sucralose, acesulfame-K, saccharin, aspartame, cyclamate (Canada) and the protein thaumatin 4), Each sweetener is unique in its perceived sensation because of the time to the onset of sweetness and to maximum sweetness, ability to mask other sensations, persistence, aftertaste and intensity relative to sucrose [TABLE IT. For example, the saccharides, sorbitol and... 

Aspartame, discovered by Mazur in 1969 (5), is 200 times sweeter than sucrose. Aspartame has a large commercial market as an artificial sweetening agent. It is apparent that the sweetness exhibited by aspartame requires amino (AH, electropositive) and carboxyl (B, electronegative) groups of aspartic acid moiety and the hydrophobic side chain (X) of the phenylalanine moiety (4). The sweetness of aspartame is exhibited by the trifunctional units AH, B, and X. It is thought that when the trifunctional units of aspartame, X, AH, and B, fit the corresponding receptor sites, a sweet taste is produced. 

Aspartame, sweetness production, 28-30 Aspartic acid, as food material, 138-147 Aspartic acid dipeptides, taste, 141-142r Astringpncy, sensation based on generalized membrane responses, 16-18 Automated data analysis and pattern recognition tool kit, 102... 

Aspartame. Aspartame [22839-47-0] [53906-69-1] (APM, L-aspartyl-L-phenylalanine methyl ester) (1), also known under the trade names of NutraSweet and EQUAL, is the most widely used nonnutritive sweetener worldwide. This dipeptide ester was synthesized as an intermediate for an antiulcer peptide at G. D. Searle in 1965. Although this compound was known in the literature, its sweet taste was serendipitously discovered when a chemist licked his finger which was contaminated with it. Many analogues, especially the more stable esters, were made (6) and their taste qualities and potencies determined. It was the first compound to be chosen for commercial development. Following the purchase of G. D. Searle by Monsanto, the aspartame business was split off to become a separate Monsanto subsidiary called the NutraSweet Company. 

Other peptides, such as L-aspartyl-L-phenylalanine methyl ester (aspartame), have a sweet taste. Several studies have been carried out to relate the structure and taste of analogs of this dipeptide (25). Tsang et al. (26) reported that the analogs at the lower end of the L-aspartyl-a-aminocycloalkanecarboxylic acid methyl ester series were sweet, the dipeptides containing a-... 

Aspartame is an intense sweetener first discovered in 1965 by J. Schlatter it is available under the brand names of Nutrasweet , Equal , and Canderel . Chemically, aspartame is N-L-a-aspartyl-L-phenylalanine methyl ester (Fig. 1), withamolecularformulaofC14H 805N2 (MW = 294.30). It is a white, odorless, crystalline powder. It is slightly soluble in water and sparingly soluble in alcohol. The solubility increases as the pH is lowered (2,6,57). It has 100-200 times the sweetness of sucrose and exhibits a sweet, clean taste and a sweetness profile similar to that of sucrose, without bitter or metallic aftertaste (Table 1). However, it displays a slow onset of sweetness coupled with lingering sweet taste. It extends and intensifies tastes and enhances fruit flavors. Aspartame exhibits synergism, a superior taste profile, and improved stability when used with other sweeteners (1,4,14,55,75). 

Alitame [L- -aspartyl-/V-(2,2,4,4-tetramethyl-3-thioethanyl)-D-alaninamide] is an amino acid-based sweetener developed by Pfizer from L-aspartic acid, D-alanine, and an amine 2,2,4,4-tetraethylthioethanyl amine (Fig. 1). Its formula is CI4H2504N3S with a molecular weight of 331.06. It is produced under the brand name Aclame . It is a crystalline, odorless, nonhygro-scopic powder that is soluble in water (130 g/L at pH 5.6) and alcohol and significantly more stable than aspartame (Table 1). Alitame is 2000 times as sweet as sucrose and has a clean, sweet taste, with no unpleasant aftertaste. It blends with other sweeteners, such as acesulfame-K, saccharin, and cyclamate, to maximize the quality of sweetness (3,7-9). 

James M. Schlatter, American chemist, combines two amino acids and obtains a sweet-tasting substance. This chemical is about 200 times sweeter than sugar and is named aspartame. In 1983, it is approved for use in carbonated beverages. It becomes the most widely used artificial sweetener. 

Aspartame exists as colorless needles (recrystallized from water) [7], It is an off-white, almost odorless crystalline powder with an intensely sweet taste [5],... 

The low energy sweetening properties of aspartame have been discussed on the basis of structural relationships [1, 83] within the context of the three point contact model of the sweet taste receptor. This model involves a hydrogen bond donor, a hydrogen bond acceptor, and a hydrophobic region with specific geometric relationships. The model accounts for the fact that only one of the four diastereomers of aspartylphenylalanyl methyl ester is sweet. 

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. 

Because of this difficulty in predicting what features are necessary for a compound to taste sweet, most of the discoveries of artificial sweeteners have been serendipitous. In fact, many of the early discoveries resulted from dangerous laboratory practices that we would not condone today. For example, the sweetness of saccharin was discovered in 1879 by a chemist who spilled some of the compound on his hand. Later, while eating lunch in the laboratory, he noticed the extremely sweet taste. The sweetness of cy-clamate was discovered in 1937 by a chemist who tasted it on a cigarette that he had set on the lab bench. And aspartame was found to be sweet by a chemist who got some on his hand and later licked his Finger before picking up a piece of paper. This resulted in a billion-dollar-per-year product ... 

Aspartame (Nutrasweet ) is a remarkably sweet-tasting dipeptide ester. Complete hydrolysis of aspartame gives phenyl alanine, aspartic acid, and methanol. Mild incubation with carboxypeptidase has no effect on aspartame. Treatment of aspartame with phenyl isothiocyanate, followed by mild hydrolysis, gives the phenylthiohydantoin of aspartic acid. 

In nature, the amino acids are combined to give proteins with hundreds or even thousands of amino acids in each one. Small assemblies of amino acids are known as peptides and die amide bond that links them is called a peptide bond. One important dipeptide is the sweetening agent aspartame, whose synthesis was discussed in Chapter 25. It is composed (and made) of the amino acid aspartic acid (Asp) and the methyl ester of phenylalanine. Only this enantiomer has a sweet taste and it is very sweet indeed—about 160 times as sweet as sucrose. 

This intense sweetener (8) is quoted as having the same effective sweetness as aspartame, but unlike aspartame it is sufficiently heat stable that it can be added at the beginning of the boil in high-boiled products. If a product with the same amount of acesulfame K is compared with one based on aspartame the taste will be different. In practice acesulfame K is not normally used on its own but is sometimes used with aspartame. Chemically, acesulfame K is the potassium salt of 6-methyl-l,2,3-oxathiazine-4(3//)-one-2,2 dioxide or 3,4-dihydro-6-methyl-l,2,3-oxathiazine-4-one 2,2-dioxide. It can be regarded as a derivative of acetoacetic acid. The empirical formula is C4H4N04KS and its molecular weight is 201.2. 

The sweet peptide, aspartame (L-Asp-L-Phe-OMe) which has a sweet taste 180 times that of sucrose, was discovered by Mazur al. (2) Aspartame is stable at pH 4 and unstable at pH 1 or 7-8. It is also unstable at high temperatures. Under these unstable conditions, the... 

Interestingly, the human TAS1R2/TAS1R3, but not its mouse counterpart, are sensitive to the sweet proteins monellin, thaumatin, and brazzein, and to the artificial sweeteners neo-tame, cyclamate, and aspartame (9-11). This difference provides a molecular explanation for the previous observation that these compounds are sweet for humans but not attractive to rodents (9). The species difference also applies to the inhibitor lactisole that blocks the sweet taste in humans but not in rats, and only inhibits the response of human TAS1R2/TAS1R3 to sweet stimuli (9). 

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