| 摘要 |
1456260 Crystallizing fructose SUOMEN SOKERI OSAKEYHTIO 9 Dec 1974 [28 Jan 1974] 53056/74 Heading B1G [Also in Division C2] Fructose crystals having a crystal size of 200 to 600 Ám are obtained by crystallizing fructose from an aqueous solution thereof, containing at least 90% by weight of dry substance of which dry substance at least 90 percent by weight is fructose, in a process which comprises (a) providing such a fructose solution (b) adjusting the pH of said solution to 4.0-6.0, preferably 4.5-5.5, (c) bringing the aqueous fructose solution to a temperature at which it is saturated with respect to fructose, (a) adding fructose seed crystals to the solution, (e) lowering the temperature of the resulting mass at a controlled rate to cause the mass to be supersaturated with respect to fructose and to bring about an increase in the crystal size of the seed crystals without substantial formation of new fructose crystals and (f) separating the fructose crystals from the mass when the crystal size is 200-600 Ám. The process may be carried out continuously using as seed crystals, crystals taken from a previous crystallization and recrystallization may be accelerated by blowing warm dry air on to the surface of the mass to evaporate water therefrom during crystallisation. The rate of crystallisation of fructose may be increased by the addition to the solution of 2-4% by weight, based on the sugar solids, of methanol, ethanol, and/or isopropanol. |
