Application of Sweetener Neotame in Food

Neotame is a new type of dipeptide strong sweetener, a derivative of aspartame (APM), known as the second generation dipeptide sweetener, its sweetness is about 7000 of sucrose-- 13,000 times, which is 30 to 60 times that of aspartame. The stability of neotame is better than that of aspartame, and the cost of use is also much lower than that of aspartame.

Physicochemical properties of neotame

Neotame, the chemical name is: N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine-1-methyl ester, is a white crystalline powder , containing about 4.5% crystal water, is a functional sweetener.

It has a pure sweetness, and a sweet synergy, very close to aspartame, without the bitterness and metallic taste that other strong sweeteners often bring. The sweetness is 7000 to 13000 times sweeter than sucrose and 30 to 60 times sweeter than aspartame. The energy value is almost zero.

It can remain stable under the condition of instantaneous high temperature. In cake production, 85% of neotame still exists after baking at a high temperature of 450 °C.

The solubility of NTM in water at 25°C is 12.6 g/L, which is similar to that of APM, but the solubility in pure ethanol is 950 g/L, which is much higher than that of APM under the same conditions.

The most stable pH value of neotame was 4.5, and the main degradation products were DMB-Asp-Phe and methanol. The NTM structure contains carboxyl and imino groups and is an amphoteric compound with pKa values of 3.03 and 8.08, respectively, and an isoelectric point of 5.5.

Therefore, NTM can form both acid and base salts, and can form complexes with metals, thereby improving its stability and other properties.

Method for improving the solubility of neotame in water

Although neotame has many excellent properties, its solubility in water is not high and the dissolution rate is relatively small, which limits the application of neotame in food production to a certain extent.

Under normal circumstances, it takes 5 to 7 minutes for 0.05 to 0.19 neotame to be completely dissolved in 100 mL of water (observation with the naked eye). 100mL of water takes about 45min.

Since neotame often needs to be used in aqueous solutions and beverages, improving the solubility and dissolution rate of neotame in water is of great significance for expanding the application range of neotame in industry and increasing its economic value. Several methods to improve the solubility of neotame in water are described below.

1) Neotame and hydrochloric acid compound

Take a certain amount of Neotame and add it to the water, stir fully until it becomes a slurry, and then slowly add the same amount of hydrochloric acid to it. After about 10 minutes, all the solids are dissolved, and then the clear solution can be obtained by freeze-drying White solid in 99.7% yield. Compared with the starting material neotame, the product exhibits great water solubility, and it only takes 70s for 1 g of the product to be completely dissolved in 100 mL of water.

2) Neotame and phosphoric acid complex

Take a certain amount of neotame and dissolve it in water, stir to make it into a slurry, then add an equimolar 85% phosphoric acid solution, after all solids are dissolved, the solution is freeze-dried, the resulting product is a white solid with a yield of 98% . The water solubility of the product has been greatly improved, and 0.1 g of the product can be completely dissolved in 100 mL of water in less than 30s (observation with the naked eye).

3) Neotame and citric acid complex

Dissolve a certain amount of neotame in acetone, slowly add an equimolar citric acid aqueous solution, and then add an appropriate amount of acetone to form a clear colorless solution, stir the solution for 1 hour, and then distill the acetone under reduced pressure. The product was freeze-dried to obtain a white solid. 0.1 g of this white solid was dissolved in 100 mL of water within 90 s (visual observation).

4) Neotame and sodium bicarbonate complex

Dissolve a certain amount of sodium bicarbonate in water, add equimolar neotame, and stir the obtained slurry liquid for 24 hours to obtain a clear solution, and freeze-dry to obtain a white solid, which is the target product. 0.1 g of white solid can be completely dissolved in 100 mL of water in an instant (observation with the naked eye).

Outlook and Outlook

Neotame's low cost and high sweetness make it highly competitive in the market. It well meets the 5 benchmarks for commercial success of non-nutritive sweeteners, namely sweetness profile, solubility, stability, safety and cost. Therefore, its application prospect is very broad.