Sweeteners, artificial aspartame

The —CO—NH - link shown in the red box is called a peptide bond, and each monomer used to form a peptide is called a residue. A typical protein is a polypeptide chain of more than a hundred residues joined through peptide bonds and arranged in a strict order. When only a few amino acid residues are present, we call the molecule an oligopeptide. The artificial sweetening agent aspartame is a type of oligopeptide called a dipeptide because it has two residues. 

This technique has been established for many years particularly for water, soil and feeding-stuff analysis, where a large number of analyses are required for quality control or monitoring purposes. A number of applications have been published for food additives including aspartame (Fatibello et al., 1999), citric acid (Prodromidis et al., 1997), chloride, nitrite and nitrate (Ferreira et al., 1996), cyclamates (Cabero et al., 1999), sulphites (Huang et al., 1999 AOAC Int, 2000), and carbonate, sulphite and acetate (Shi et al., 1996). Yebra-Biumm (2000) reviewed the determination of artificial sweeteners (saccharin, aspartame and cyclamate) by flow injection. 

A child with white-blond hair, blue eyes, and pale complexion is on a special diet in which one of the essential amino acids is severely restricted. He has been told to avoid foods artificially sweetened with aspartame. 

Phenylketonuria was among the first inheritable metabolic defects discovered in humans. When this condition is recognized early in infancy, mental retardation can largely be prevented by rigid dietary control. The diet must supply only enough phenylalanine and tyrosine to meet the needs for protein synthesis. Consumption of protein-rich foods must be curtailed. Natural proteins, such as casein of milk, must first be hydrolyzed and much of the phenylalanine removed to provide an appropriate diet, at least through childhood. Because the artificial sweetener aspartame is a dipeptide of aspartate and the methyl ester of phenylalanine (see Fig. l-23b), foods sweetened with aspartame bear warnings addressed to individuals on phenylalanine-controlled diets. 

The sweeteners used in soft drinks can be divided into two main categories. These are the natural sweeteners, such as sucrose, invert syrups, corn-derived syrups and honey, and the high-intensity sweeteners (artificial sweeteners) such as saccharin, aspartame and acesulfame K. In most fruit juices and many soft drinks, except diet vaiieties, sugars are a major component of the product. 

Sweet hazard. Why should phenylketonurics avoid using aspartame, an artificial sweetener (Hint Aspartame is 1-aspartyl-l-phenylalanine methyl ester.)... 

Aspartame (NutraSweet), which has replaced saccharin as the principal artificial sweetener, is used in more than 3000 products and accounts for 75% of the one-hiUion-dollar worldwide artificial sweetener market. It is a dipeptide derivative made from aspartic acid and the methyl ester of phenylalanine. Aspartame can he digested, and its caloric value is approximately equal to that of proteins. However, since much smaller amounts of aspartame than of table sugar are needed for sweetness, many fewer calories are consumed in the sweetened food. Aspartame is not stable at cooking temperatures, which limits its use as a sugar substitute to cold foods and soft drinks. 

Perhaps the most successful and widely used artificial sweetener is aspartame, the methyl ester of a dipeptide formed from phenylalanine and aspartic acid. Aspartame is roughly 100 times as sweet as sucrose. It undergoes slow hydrolysis in solution, however, which limits its shelf life in products such as soft drinks. It also cannot be used for baking because it decomposes with heat. Furthermore, people with a genetic condition known as phenylketonuria cannot use aspartame because their metabolism causes a buildup of phenylpyruvic acid derived from aspartame. Accumulation of phenylpyruvic acid is harmful, especially to infants. Alitame, on the other hand, is a compound related to aspartame, but with improved properties. It is more... 

Sucralose is a trichloro derivative of sucrose that is an artificial sweetener. Like aspartame, it is also approved for use by the U.S. Food and Drug Administration (FDA). Sucralose is 600 times sweeter than sucrose and has many properties desirable in an artificial sweetener. Sucralose looks and tastes like sugar, is stable at the temperatures used for cooking and baking, and it does not cause tooth decay or provide calories. 

Some artificial sweeteners contain aspartame, which is an ester of a dipeptide. 

There are thousands of breweries worldwide. However, the number of companies using fermentation to produce therapeutic substances and/or fine chemicals number well over 150, and those that grow microorganisms for food and feed number nearly 100. Lists of representative fermentation products produced commercially and the corresponding companies are available (1). Numerous other companies practice fermentation in some small capacity because it is often the only route to synthesize biochemical intermediates, enzymes, and many fine chemicals used in minor quantities. The large volume of L-phenylalanine is mainly used in the manufacture of the artificial dipeptide sweetener known as aspartame [22389-47-0]. Prior to the early 1980s there was httle demand for L-phenyl alanine, most of which was obtained by extraction from human hair and other nonmicrobiological sources. 

Fumaric acid and malic acid [6915-15-7] are produced from maleic anhydride. The primary use for fumaric acid is in the manufacture of paper siting products (see Papermaking additives). Fumaric acid is also used to acidify food as is malic acid. Malic acid is a particularly desirable acidulant in certain beverage selections, specifically those sweetened with the artificial sweetener aspartame [22839-47-0]. 

There are numerous further appHcations for which maleic anhydride serves as a raw material. These appHcations prove the versatiHty of this molecule. The popular artificial sweetener aspartame [22839-47-0] is a dipeptide with one amino acid (l-aspartic acid [56-84-8]) which is produced from maleic anhydride as the starting material. Processes have been reported for production of poly(aspartic acid) [26063-13-8] (184—186) with appHcations for this biodegradable polymer aimed at detergent builders, water treatment, and poly(acryHc acid) [9003-01-4] replacement (184,187,188) (see Detergency). 

Aspartame is the market leader among artificial sweeteners. It is a methyl ester of a dipeptide, unrelated to any carbohydrate. It was discovered in the course of research directed toward developing drugs to relieve indigestion. 

Examine the structures oisucrose, the natural sweetener, and saccharin, sodium cyclamate and aspartame (Nutrasweet), three of the most common artificial sweeteners. What, if any, structural features do these molecules have in common Compare electrostatic potential maps for the different sweeteners. Are there any significant features in common Based on yom findings, do you think it is likely that entirely different artifical sweeteners might be discovered Explain. 

Different optical enantiomers of amino acids also have different properties. L-asparagine, for example, tastes bitter while D-asparagine tastes sweet (see Figure 8.3). L-Phenylalanine is a constituent of the artificial sweetener aspartame (Figure 8.3). When one uses D-phenylalanine the same compound tastes bitter. These examples clearly demonstrate the importance of the use of homochiral compounds. 

Odier dragp are taken 1 hour before or 4 to 6 hours after cholestyramine Cholestyramine is available combined widi die artificial sweetener, aspartame (Questran Light), for patients widi diabetes or diose who are concerned with weight gain. 

Neotame is an artificial sweetener designed to overcome some of the problems with aspartame. The dimethylbutyl part of the molecule was added to block the action of peptidases, enzymes that break the peptide bond between the two amino acids aspartic acid and phenylalanine. This reduces the availability of phenylalanine, eliminating the need for a warning on labels directed at people who cannot properly metabolize phenylalanine. 

The artificial sweetener aspartame is the low-calorie sweetener of choice at the time of this writing, having replaced cycla-... 

F.4 What is the mass percentage composition of aspartame, CI4H 8N205, an artificial sweetener sold as NutraSweet ... 

H.16 Aspartame, C14H gN205, is a solid used as an artificial sweetener. Write the balanced equation for its combustion to carbon dioxide gas, liquid water, and nitrogen gas. 

C13-0115. The artificial sweetener aspartame (NutraSweet) is Ihe methyl ester of Ihe following dipeptide ... 

Another advantage of biocatalysis is that chemo-, regio-, and stereoselectivities are attainable that are difficult or impossible to achieve by chemical means. A pertinent example is the production of the artificial sweetener, aspartame, which has become somewhat of an industrial commodity. The enzymatic process (Fig. 2.31), operated by the Holland Sweetener Company (a joint venture of DSM and Tosoh), is completely regio- and enantiospecific (Oyama, 1992). 

The artificial sweeteners erythritol, sodium saccharin, and aspartame (Fig. 25) were also studied. Figure 26 shows potential oscillation in the presence of these artificial sweeteners [22]. The oscillation modes of these substances differed considerably. For erythritol above 10 mM, Fa.sds slightly shifted to more negative potentials. and Fb.sds were essentially unaffected by this sweetener. Erythritol thus induces change in the oscillation mode in much the same way as sugars. At 1 mM-1 M sodium saccharin, E and Fa.sds shifted to more negative values with increase in its concentration. For aspartame at less than 10 mM, there was no change in potential. 

Aspartame, a dipeptide (aspartic acid + phenylalanine) artificial sweetener marketed under the trade name Nutrasweet... 

Chen et al. (1997a) analysed sodium saccharin in soft drinks, orange juice and lemon tea after filtration by injection into an ion-exclusion column with detection at 202 nm. Recoveries of 98-104% were obtained. They reported that common organic acids like citric and malic and other sweeteners did not interfere. Qu et al. (1999) determined aspartame in fruit juices, after degassing and dilution in water, by IC-PAD. The decomposition products of aspartame, aspartic acid and phenylanaline were separated and other sweeteners did not interfere. The recoveries of added aspartame were 77-94%. Chen et al. (1997b) separated and determined four artificial sweeteners and citric acid. 

That derivatization may increase rather than decrease peptidase-catalyzed degradation is illustrated with aspartame (6.79, R = MeO), the C-terminal methyl ester of the dipeptide Asp-Phe. The metabolism of this artificial sweetener was compared to that of the underivatized dipeptide (6.79, R = H) and of the corresponding amide Asp-Phe-NH2 (6.79, R = NH2) in microvillar membranes obtained from human duodenum, jejunum, and ileum [189]. The activities monitored were clearly those of peptidases as shown by the effects of inhibitors. Whereas the peptide bond in Asp-Phe and Asp-Phe-NH2 was hydrolyzed at a comparable rate, that in aspartame was hydrolyzed approximately twice as fast. This is an interesting and favorable situation, given that aspartame is expected to be degraded once it has elicited its effect in the buccal cavity. 

Abstract Aspartame (Apt), Acesulfame-K (Ace-K) low-calorie, high-potency artificial sweeteners ate cnnently nsed in beverages and dietary food and drinks. Their increased application in food and drink prodncts has given a new impetus to develop fast and accurate methods for their determination. Absorption spectra of Asp, Caf, Ace-K and BA strongly overlap. Therefore a direct determination of these analytes in quaternary mixture is impossible without a separation step. In order to overcome this difficulty partial least squares (PLS) method has been proposed. 

In this present work, an alternative PLS-2 method was investigated and applied to the determination of sodium benzoate (itsed for preservatives) artificial sweeteners Aspartame, Acesitlfame-K and caffeine in diet cola drinks. 

Phenylalanine (Phe or F) (2-amino-3-phenyl-propanoic acid) is a neutral, aromatic amino acid with the formula HOOCCH(NH2)CH2C6H5. It is classified as nonpolar because of the hydrophobic nature of the benzyl side chain. Tyr and Phe play a significant role not only in protein structure but also as important precursors for thyroid and adrenocortical hormones as well as in the synthesis of neurotransmitters such as dopamine and noradrenaline. The genetic disorder phenylketonuria (PKU) is the inability to metabolize Phe. This is caused by a deficiency of phenylalanine hydroxylase with the result that there is an accumulation of Phe in body fluids. Individuals with this disorder are known as phenylketonurics and must abstain from consumption of Phe. A nonfood source of Phe is the artificial sweetener aspartame (L-aspartyl-L-phenylalanine methyl ester), which is metabolized by the body into several by-products including Phe. The side chain of Phe is immune from side reactions, but during catalytic hydrogenations the aromatic ring can be saturated and converted into a hexahydrophenylalanine residue. ... 

Infants with classic phenylketonuria (PKU) are normal at birth but if untreated show slow development, severe mental retardation, autistic symptoms, and loss of motor control. Children may have pale skin and white-blonde hair. The neurotoxic effects relate to high levels of phenylalanine and not to the phenylketones from which the name of the disease derives. Infants are routinely screened a few days after birth for blood phenylalanine level. Treatment consists of a life-long semisynthetic diet restricted in phenylalanine (smalt quantities are necessary because it is an essential amino acid). Aspartame (N-aspartyl-phenylalanine methyl ester), which is widely used as an artificial sweetener, must be strictly avoided by phenyiketonurics. 

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