Aspartame function

The efficiency of this method was demonstrated by the elegant two-step synthesis of aspartame [87], Protection of the a-amino group and activation of the a-carboxylic group are accomplished in only one step Deprotection of the amino functionality occurs during aminolysis, such as with methyl phenylalaninate (H-Phe-OMe in equation 15)... 

Aspartame, N-a-L-aspartyl-L-phenylalanine methyl ester, trade names NutraSweet , and Aspartil , is a dipeptide derivative. Like dipeptides aspartame is metabolised into the constituents, i.e. amino acids and methanol. Therefore studies into the metabolic behaviour and the fate of metabolites were carried out. Levels of blood aspartate and glutamate were measured after intake of high aspartame doses. Changes were transient and allegations of influences of high aspartame levels on brain function could never be verified. 

N and O function into the molecule and has been used to prepare hydroxyarginines (136,137), hydroxyornithines (136-138), p-lysine, p-leucine, and p-phenyl-p-alanine (139,140), the low-calorie sweetener aspartame (141) and the antitumor antibiotic acivicin (142-144). 

Invertcd-Aspartame-Type Sweetener, Ac-Phe-Lys-OH, was synthesized in one step in the organic-aqueous solvent media. Maximum yield was 10%. But considering collection of enzyme and raw materials, we think that this synthesis is able to be industrialized. We also think that this modified technique can be applied to the preparation of another modified enzyme. There are a few small problems in these two methods. But we hope that these two methods will be made full use as synthetic strategies of flavor peptides or the other functional peptides. 

No generalizations can be made about the molecular weights of biologically active peptides and proteins in relation to their functions. Naturally occurring peptides range in length from two to many thousands of amino acid residues. Even the smallest peptides can have biologically important effects. Consider the commercially synthesized dipeptide L-aspartyl-L-phenylalanine methyl ester, the artificial sweetener better known as aspartame or NutraSweet. 

Figure 4.2 Managing pH for shelf-life Aspartame stability as a function of pH range 1-7. Source Ajinomoto Aspartame Technical Bulletin (2003).

Neotame is an amino acid derivative and is, therefore, hydrolysed under conditions of low or high pH. Its stability will be a function of pH, temperature and time. The optimum pH range is similar to that for aspartame pH 3.2 1.5. In dry form neotame is stable. Products containing neotame and processed by high-temperature short-time (HTST) do not show significant losses to degradation of neotame (The NutraSweet Company, 2003). 

Identify the functional groups in phenylalanine (an amino acid and component of aspartame and proteins) and vanillin (vanilla scent) ... 

In three non-obese individuals (two women and one man), it was suspected that heavy use of aspartame was causally related to symptoms of carpal tunnel syndrome (20). All three reported moderate pain and tingling in the hands, especially at night, using a self-administered questionnaire for the assessment of severity of symptoms and functional status (21). Given the ubiquity of aspartame— one manufacturer has stated that it is used in 5000 products—physicians may want to inquire about its use in patients who report symptoms of carpal tunnel syndrome. 

Although aspartame has been reported to cause hyperactivity and behavioral problems in children, a double-blind controlled trial of 48 preschool-age children fed diets containing a daily intake of 38 13 mg/kg body-weight of aspartame for 3 weeks showed no adverse effects attributable to aspartame, or dietary sucrose, on children s behavior or cognitive function. ... 

Rate constants for aspartame degradation as a function of distance from Tg. ( ) = 0.33, (o)... 

The chemical structure of the artificial sweetener aspartame is below. Identify all of the organic functional groups that it contains. 

Similar concerns have been voiced regarding the safety of the acidic amino acid Asp in the artificial sweetener aspartame (L-aspartyl-L-phenylalanine methylester). As with MSG, however, the homeostatic mechanisms regulating plasma Asp levels following Asp consumption do not allow for large increases in plasma Asp that could alter CNS function. In fact, the concern regarding the safety of aspartame results from the other amino acid phenylalanine, which much more readily crosses the blood-brain barrier and can alter CNS function. This is especially important for people who unknowingly are heterozygous for phenylketonuria (2). 

Thaumatin is a group of intensely sweet basic proteins isolated from the fruit of Thaumatococcus danielli (West African Katemfe fruit). It consists essentially of the proteins Thaumatin I and Thaumatin II. Thaumatin is a taste-modifying protein that functions as natural sweetener or flavor enhancer. Thaumatin is stable in aqueous solutions between pH 2.0 and 10 at room temperature. As occurs with aspartame it is nutritive, containing 4kcalg , but due to its intense sweetness, the amounts used are small enough for thaumatin to be considered and classified as a nonnutritive sweetener. Thaumatin is approved for a number of uses in UK, Japan, Australia, the EU, and in many other countries. In the USA, it is approved as a flavor enhancer. 

FIG. 14 Partial (a) DSC (rate of heat flow as a function of temperature) and (b) DTG curves (dehydration peaks only) showing the difference between commercial (Nutrasweet) aspartame (curves 1) and aspartame recrystallized from water/isooctane/AOT microemulsions (APM ni, curves 2). In diagram (a) the enthalpy changes, AW, associated with dehydration were calculated by integration of the respective peak area. Scanning rate 10°C/ min. (Adapted from Ref. 107.)... 

Many familiar substances are oiganic compounds. Some examples include aspartame, the artificial sweetener in the sugar substitute Equal and in many diet sodas salicylic acid, found in some acne medicines and wart-removal treatments and amphetamine, a stimulant used to treat narcolepsy. attentiMi-defidt hyperactivity disorder (ADHD), and obesity. Identify the functional groupfs) in each molecule ... 

Fig. 8.5. Relative sweetening strength of some sweeteners as a function of the saccharose concentration ( neo-hesperidin dihydrochalcone, A saccharin, o aspartame, acesulfame K) (according to Bar et al, 1990)...

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