| 摘要 |
Production of anhydrous crystalline fructose from an aqueous solution thereof wherein an aqueous solution of fructose with a pH of 3.5 to 8, preferably 5 to 6.5, and a fructose content of at least 95% referred to the dry material is concentrated in a vacuum to a water content of 2 to 5%, preferably 2.5 to 3.5%; cooled to 60 DEG to 85 DEG C. until a kneadable crystalline mass is formed; the kneadable crystalline mass is allowed to solidify slowly; is comminuted and is subsequently dried at a temperature below 65 DEG C., preferably 40 DEG to 60 DEG C. The seeding may be carried out using about 10% of a seed material such as anhydrous crystalline fructose, e.g. obtained by crystallization from methanol or ethanol, or with a non-dried crystalline mass of kneadable fructose. The process may be carried out continuously by dosing the concentrated fructose solution into a seed bed and removing well-crystallized material at the same rate. In a preferred continuous process the fructose solution is continuously concentrated in a vacuum, dosed into the seed bed, the kneadable crystalline mass obtained is fed to a kneading screw conveyer which may be heated or cooled, and the "ripened" crystaline mass is continuously removed from the screw conveyer, comminuted and subsequently dried. |
