Aspartame

• BPAspartame
• Ph. Eur.Aspartame
• USP–NFAspartame

Aspartamum; L-α-aspartyl-L-phenylalanine methyl ester; Canderel; Equal; NutraSweet; E951

Methyl L-α-aspartyl-L-phenylalaninate · [22839-47-0]

UNII Z0H242BBR1 · PubChem CID 134601

C14H18N2O5 · 294.30

Sweetening agent

Typical concentrations: — · Dosage forms: Solid, Liquid

An intense sweetener used in chewable tablets, powder mixes, sachets, effervescent products, oral liquids and many foods and beverages. It enhances some flavours and is often blended with acesulfame potassium. Levels are chosen to taste and are usually small fractions of a per cent of the formulation.

A white, almost odourless, crystalline powder with an intensely sweet taste.

Sweetness

about 180–200 times that of sucrose

Solubility

sparingly soluble in water (about 1% at room temperature; higher in acidic solution and when warm); slightly soluble in ethanol

pH of maximum stability

≈ 4.3

Isoelectric point

≈ 5.2

Energy value

4 kcal/g, but negligible at sweetening levels

Stable in dry conditions. In solution, and in moist solids, it hydrolyses to aspartylphenylalanine and cyclises to a diketopiperazine, with loss of sweetness; degradation is slowest at about pH 4.3 and increases with temperature, so it is unsuitable for products that are heated for long periods. Store in a well-closed container in a cool, dry place.

Reported to degrade in contact with dibasic calcium phosphate and, in the presence of moisture, with magnesium stearate. It can react with reducing sugars and with aldehyde-containing flavours, and is incompatible with strong oxidising agents.

Made by coupling L-aspartic acid (with the amino group protected) and L-phenylalanine methyl ester by chemical or enzymatic methods, followed by deprotection and purification.

Metabolised to aspartic acid, phenylalanine and methanol, in amounts comparable to those from ordinary foods. It must be avoided by people with phenylketonuria, and products containing it must carry a phenylalanine warning. JECFA and EFSA have set an ADI of 40 mg/kg body weight; in 2023 IARC classified aspartame as 'possibly carcinogenic' (Group 2B), while JECFA concluded there was no reason to change the ADI.

Observe normal precautions for the quantity handled. Avoid generating dust; eye protection and gloves are recommended.

Approved by the FDA as a food additive (sweetener). Accepted as a food additive in Europe (E951), with mandatory labelling that the product contains a source of phenylalanine. Included in the FDA Inactive Ingredient Database (oral preparations) and in non-parenteral medicines licensed in Europe.

Acesulfame potassium; alitame; neotame; saccharin; sucralose; aspartame–acesulfame salt.

In liquid medicines the shelf-life sweetness can fall noticeably unless the pH is kept close to 4–5; in solid dosage forms the main risk is degradation in moist blends with reactive excipients. The phenylalanine content per dose should be stated in the product information.