A process development for the bundling crystallization of aspartame

It is known that rod-like crystals of aspartame, in which several needle crystals appear to be bundled together (bundle-like crystals), have remarkably improved physical properties compared to the crystals obtained from a conventional stirred crystallizer. A crystallization process for obtaining bundle-like crystals has been developed for manufacturing practice. The conditions to obtain the bundle-like crystals are that crystallization must be carried out without stirring, with a high initial concentration of aspartame so that the amount of precipitated solid after cooling is about 10 g litre−1 or more, and with rapid cooling to produce high supersaturation. A new type of crystallizer was developed for large-scale crystallization under these conditions. The pilot plant work was carried out in a 400-litre crystallizer, and it has been demonstrated that the crystallization process is technically possible and economically successful in the large-scale manufacturing of aspartame.