| This paper took the corn starch as raw material. Different kinds of enzyme for the liquefication, the saccharification and the isomerization of starch been used. The fructose and glucose been separated by the ion exchange resin chromatograph. The high-purity crystallization fructose got from the solvent crystallization . The best technological conditions of each steps were ascertained. The results as below:(1) The best technological conditions of liquefication and saccharification for the starch were ascertained. The best technological conditions of single factor experiments were: in liquefication liquefication time 30min, the thermostable a-amylase diluted 100 times 0.08mL/g starch and the starch solution concentration 36%; in saccharification: the Dextrozyme diluted 100 times 0.2mL/g starch, saccharification time 51.5h. Through the orthogonal experiments, the best technological condition was: liquefication time 40min, the thermostable a-amylase diluted 100 times 0.08mL/g starch, saccharification time 52h, the Dextrozyme diluted 100 times 0.19mL/g starch, the starch solution concentration 39%. Through the best technological condition glucose syrup with DE value 99.63 was obtained.(2) The resin group composed of 701 strong acid styrene series cation exchange resin and the D311 weak basic acrylic series anion exchange resin was used to purify the glucose syrup. After the purification the glucose syrup conductivity was 2μΩ-1 cm-1,pH was 7.0, the color value was 0, DE value was 99.51. The glucose syrup was colorless, the conductivity was very low, the quality of syrup was not affected nearly.(3) The best technological conditions of isomerization for the glucose syrup were ascertained. The best technological conditions of single factor experiments were: the flow velocity 2.35mL/min the glucose syrup concentration 45%, the dosages of Sweetzyme 0.4mL/mL glucose syrup, Through the orthogonal experiments, the best technological condition was: the flow velocity of glucose syrup 2.35mL/min, glucose syrup concentration 40%, dosages of Sweetzyme 0.6mL/mL glucose syrup.Through the best technological condition fructose glucose syrup with fructose concentration 43.27% was obtained. (4) The resin group composed of 701 strong acid styrene series cation exchange resin and the D311 weak basic acrylic series anion exchange resin was used to purify the glucose syrup. After the purification the syrup conductivity was 11.1μΩ-1 cm-1, pH was 7.0, the color value was 0, The sugar fluid was colorless, the conductivity was very low. Pigment and ion were removed from syrup clearly.(5) The best technological conditions of separation for fructose and glucose were ascertained. The best technological conditions of single factor experiments were: the best separation temperature 60℃, the syrup concentration 30%, the flow velocity 0.35BV/h, the quantity of syrup 0.017BV. Through the orthogonal experiments, the best technological condition was: the separation temperature 70℃, the syrup concentration 20%, the flow velocity of syrup 0.55BV/h, the quantity of syrup 0.017BV. Through the best technological condition fructose syrup with fructose concentration 94.5%, the conductivity 15.2μΩ-1 cm-1, pH 6.2 and the color value 6.8 was obtained.(6) The best technological conditions of crystallization for fructose were ascertained. The best technological conditions of single factor experiments were: the best solid-liquid ratio was 1:12, the syrup concentration 80%, the temperature difference 65—5℃, the crystallization time 72h. Through the orthogonal experiments, the best technological condition for fructose purity was: the solid-liquid ratio 1:14, the syrup concentration 80%. temperature difference 65—5℃, crystallization time 84h. Through the best technological condition the fructose with purity 95.97% was obtained. Through the orthogonal experiments, the best technological condition for fructose extraction rate was: the solid-liquid ratio 1:14, the syrup concentration 80%. temperature difference 60—5℃, crystallization time 84h. Through the best technological condition the fructose with extraction rate 86.83% was obtained. The overall evaluation, optimum technological condition for fructose crystallization was: the solid-liquid ratio 1:14, the syrup concentration 80%, temperature difference 60—5℃crystallization time 84h.In conclusion: (1) the processing of high purity crystalline Fructose was: corn starch→liquefication→saccharification→purification of glucose syrup→glucose syrup isomerization→purification of fructose glucose syrup→separation of fructose and glucose→fructose crystallization→high purity crystalline fructose . (2)The best condition of high purity crystalline fructose was: in liquefication: liquefied time 40min, the dosages of a-amylase 0.08mL/g, the starch solution concentration 39%; in saccharification: saccharification time 52h, the dosages of Dextrozyme 0.19mL/g; in isomerization: the flow velocity of glucose syrup 2.35mL/min, glucose syrup concentration 40%, dosages of Sweetzyme 0.6mL/mL glucose syrup; in crystallization: the solid-liquid ratio1:14, the syrup concentration 80%, temperature difference 60—5℃, crystallization time 84h. (3) According to the best condition, three amplied experiments had been done(every time 2kg com starch had been used). The average purity of crystalline fructose was 95.8%.
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