The physical and chemical properties of aspartame

Aspartame is commonly known as aspartame, and its chemical formula is C14H18N2O5. It exists as a white powder at room temperature. It is a natural functional oligosaccharide with high sweetness, not easy to deliquesce, and does not cause dental caries. Diabetic patients can edible. Because of its extremely low calories and high sweetness, aspartame can be added to beverages, pharmaceutical products or sugar-free chewing gum as a sugar substitute. 1 g of aspartame can release about 4186 kJ/kg of calories, and 2.8 mg/dl of aspartame can make people feel sweet, so the calories produced by a small amount of aspartame can be ignored.

stability

The ester bond of aspartame aqueous solution can be hydrolyzed to produce aspartyl phenylalanine and methanol under certain temperature and acidic pH conditions. Under neutral, alkaline (pH>7) or heated conditions, or through cyclization to eliminate methanol to form cyclic aspartyl phenylalanine. Eventually, aspartyl phenylalanine will continue to be hydrolyzed to produce two separate amino acids-aspartic acid and phenylalanine.

Aspartame has a half-life of up to 300 days and is most stable in an environment with a pH of 3 to 5; when the pH is 7, the half-life is only a few days. The sweetness of aspartame is different from that of sucrose. It has a more lasting sweetness than sucrose, and it will not have a bitter aftertaste or metallic peculiar smell after consumption. Moreover, aspartame can be rapidly metabolized and decomposed into the sky in the human body. Aspartic acid, phenylalanine and methyl ester, the methyl ester content is extremely low, and the metabolism is fast, which can be quickly absorbed by the human body and is not easy to detect.

Stability in food and beverage

In dry products such as solid powder beverages and mixed snacks, aspartame has good stability, and the overall stability is similar to pure aspartame. Aspartame will undergo hydrolysis and cyclization in a high temperature environment, which limits its application in baking and frying foods that require high temperature and long-term processing. But if handled properly, aspartame can also be used in foods that require a certain degree of heat treatment, such as foods that require high temperature and short-term sterilization (132-138°C, 1 min). Under other extreme conditions, such as frozen or quick-frozen food, the amount of aspartame that changes directly is very small. To

Due to the combined effects of moisture, pH and temperature, the decomposition of aspartame will cause the gradual loss of sweetness. But this will not produce a strange smell, because the transformants are all tasteless.

Solubility

The solubility of aspartame is an important parameter, which must be taken into consideration when applied to liquid foods. As for aspartame itself, its solubility is a function of pH and temperature. When preparing table sweeteners, beverages and sweet assorted snacks, the combined influence of these factors must be fully considered.

Aspartame has the smallest solubility in water with its isoelectric point (pH 5.2), and its solubility increases with increasing temperature. At the isoelectric point, there is a linear relationship between temperature and solubility. The tendency to form a salt solution below the isoelectric point of aspartame helps to improve the dissolution rate and degree of dissolution. This can be done by first dissolving an edible acid (citric acid, malic acid, etc.) in the system, and then It can be achieved by adding aspartame, or by adding both at the same time.