Method for crystallizing compound sugar solution of xylose and sucrose

A method for crystallizing a compound sugar solution of xylose and sucrose, comprising:

• (a) weighing sucrose crystals and xylose crystals, mixing weighted sucrose crystals and weighted xylose crystals to obtain a mixture consisting of the sucrose crystals and the xylose crystals, adding deionized water to the mixture consisting of the sucrose crystals and the xylose crystals, stirring and dissolving at a temperature in a range of 75° C.-80° C. to obtain a mixed solution consisting of the sucrose and the xylose;
• (b) introducing the mixed solution into a crystallization device, setting a stirring speed in a range of 60 rpm-120 rpm, a temperature in a range of 75° C.- 80° C., and a vacuum pump pressure in a range of 50 mbar-200 mbar, turning on a vacuum evaporation device, evaporating the mixed solution until a Brix value of the mixed solution reaches a range of 78 Brix-81 Brix, and stopping the vacuum evaporation to obtain an evaporated mixed solution;
• (c) adjusting the temperature to a range of 70° C. -75° C., adding food-grade isopropanol solution or ethanol solution dropwise to the evaporated mixed solution, adding sucrose seed crystals, and continuing stirring to obtain a solution, wherein a mass of the sucrose seed crystals accounts for 0.5%-2% of a mass of the sucrose crystals in operation (a) and a particle diameter of the sucrose seed crystals is 60 mesh or 80 mesh;
• (d) when seed crystals grow in the solution, dropping the temperature to a range of 40° C.-60° C. at a rate of 10° C./h, and then stirring for 6 h to obtain the compound sugar solution;
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• (e) centrifuging the compound sugar solution, and drying a centrifuged solid at the temperature in the range of 40° C.-60° C. to obtain a finished product of the compound sugar crystals of the xylose and the sucrose.