Aspartam

BeschreibungAspartame is the most popular artificial sweetener in the United States. It is sold as sweeteners such as NutraSweet and Equal, but it is also incorporated into thousands of food products.

HistoryAspartame was discovered accidentally in 1965 during a search for drugs to treat gastric ulcers. James M. Schlatter, an organic chemist working for G. D. Searle & Company, was using aspartyl-phenylalanine methyl ester (aspartame) in a synthesis procedure and inadvertently got some of the compound on his hands.

VerwendenAspartame is a high-intensity sweetener that is a dipeptide, provid- ing 4 cal/g. it is synthesized by combining the methyl ester of phenylalanine with aspartic acid, forming the compound n-l-alpha- aspartyl-l-phenylalanine-1-methyl ester. it is approximately 200 times as sweet as sucrose and tastes similar to sugar. it is compara- tively sweeter at low usage levels and at room temperature. its mini- mum solubility is at ph 5.2, its isoelectric point. its maximum solubility is at ph 2.2. it has a solubility of 1% in water at 25°c. the solubility increases with temperature. aspartame has a certain insta- bility in liquid systems which results in a decrease in sweetness. it decomposes to aspartylphenylalanine or to diketropiperazine (dkp) and neither of these forms is sweet. the stability of aspartame is a function of time, temperature, ph, and water activity. maximum stability is at approximately ph 4.3. it is not usually used in baked goods because it breaks down at the high baking temperatures. it contains phenylalanine, which restricts its use for those afflicted with phenylketonuria, the inability to metabolize phenylalanine. uses include cold breakfast cereals, desserts, topping mixes, chew- ing gum, beverages, and frozen desserts. the usage level ranges from 0.01 to 0.02%.

synthetischeBy coupling the amino acids L-phenylalanine and L-aspartic acid, and the esterification of the carboxyl group of the phenylalanine moiety to produce the methyl ester. This esterification can occur before or after coupling. The crystallized slurry is centrifuged and the resulting “wet-cake” is washed to remove impurities.