CN100385016C - Method for producing crystalline fructose from cornstarch - Google Patents

Abstract

The invention discloses a method for producing crystalline fructose from cornstarch, which relates to the field of sugar production technology. The process uses corn as raw material, after concentration, isomerization chromatographic separation, evaporation, crystallization and other processes, by controlling the parameters in the crystallization and other steps, it not only solves the defect of difficult fructose crystallization, but also reduces the energy consumption per unit product.

Description

Method for producing crystalline fructose from cornstarch

Technical field:

The invention relates to the field of sugar production methods, in particular to a method for producing crystalline fructose from cornstarch.

Background technique:

In the prior art, the production of crystalline fructose mainly includes the following methods in terms of raw materials: using sucrose as raw material, hydrolysis to obtain a mixture of fructose and glucose, and separation by adsorption to obtain high-purity fructose and glucose, and crystallization and separation of high-purity fructose , crystalline fructose can be obtained, but the yield of this method is low. Under the action of mannitol isomerase, mannitol is produced into a fructose solution, which can be recrystallized to obtain fructose, but the source of mannitol is problematic, so it is not advisable. The hydrolysis of inulin can be 100% converted into fructose, but the industrial production of inulin sources is difficult and not advisable.

my country is a large agricultural country. Corn is the main food crop in my country, and its total output is second only to rice and wheat, ranking second in the world. Corn has the advantages of fast maturity, high yield, wide planting area, high starch content in grain, many varieties of by-products, high value, easy transportation and storage, and can be processed and produced throughout the year.

However, the process of producing crystalline fructose from corn is very difficult, especially the crystallization difficulty in the fructose crystallization step has always been an insurmountable obstacle.

Invention content:

Aiming at the defects existing in the prior art, the present invention solves the crystallization difficulty in converting glucose into crystalline fructose by controlling the process parameters in the process of chromatographic separation, evaporation concentration, crystallization, etc., and provides a method for producing fructose with cornstarch as raw material. crystallization method.

Technical scheme of the present invention comprises the steps of following order:

a. Corn is used as raw material, soaked, degermed, finely ground, sieved to remove fiber and protein, and then washed many times to obtain refined starch milk;

b. Continuous jet liquefaction, saccharification and other processes are used to obtain saccharified liquid from refined starch milk, and the obtained saccharified liquid is evaporated and concentrated into glucose concentrate by multi-effect falling film evaporator;

c the glucose in the glucose concentrate is partially converted into fructose through an isomerization reaction;

Pass the concentrated glucose solution through an immobilized isomerase column to obtain F42 fructose syrup. The parameters controlled during the isomerization process are: the dry matter of the feed sugar solution is 40% to 50%, the purity is 94% to 96%, and the pH is 7 .5 ~ 8.2, isomerization temperature 55 ~ 65 ℃, isomerization time 0.5 ~ 4h, control the calcium ion less than 1ppm, add magnesium sulfate during the isomerization process, so that the magnesium ion content reaches more than 36ppm for the activation of isomerase agent;

D above-mentioned F 42 type fructose syrup is separated by chromatographic separation, obtains high-purity fructose aqueous solution;

Use simulated moving bed for chromatographic adsorption separation to achieve the purpose of separating fructose and glucose; simulated moving bed, in which the parameters for chromatographic separation control are: feed total sugar concentration 0.10~0.45g/mL, feed flow rate: 8~40mL /min; when the feed liquid is full, open the flushing valve, the flushing liquid flow rate: 60-120mL/min; during the flushing process, the liquid phase flow rate in the bed: 2-5mL/min, and the liquid flow rate is controlled at 3-4mL/min ; During the separation process, we must pay attention to the change of temperature. Low temperature cannot achieve the separation effect, and high temperature is not easy to operate. The temperature is generally controlled between 65 ° C and 70 ° C;

After the separation operation of the simulated moving bed, the fructose content in the obtained product reaches more than 90%, which is refined and concentrated into a high-purity fructose aqueous solution for the production of crystalline fructose;

e evaporation concentration

First, use a multi-effect falling film evaporator to evaporate and concentrate the high-purity fructose aqueous solution obtained from the above separation to 70% to 75% of dry matter. The multi-effect falling film evaporator can use a five-effect falling film evaporator or a four-effect falling film evaporator;

Then use the vacuum scraper evaporator to continue to evaporate the dry matter to between 90% and 95%;

When the fructose liquid obtained after separation is evaporated to between 70% and 75% of the dry matter by a multi-effect falling film evaporator, it is difficult to increase the dry matter by using a multi-effect evaporator at this time, and it is easy to cause an increase in color and easy sugar liquid Stick to the wall of the container, so use a vacuum scraper evaporator to achieve dry matter and continue to evaporate to between 90% and 95%;

crystallization

Pass the above-mentioned concentrated fructose concentrate through a crystallizer, stir and cool. During the crystallization process, the seed crystal dosage is 8-12%, and the crystallization time is 25-30 hours. During the crystallization process, the pH is controlled at 3.5-5.0, and the temperature is 45-65°C , the degree of supersaturation is 1.1~1.25, the temperature difference between the cooling unit of the crystallizer and the feed liquid unit is less than 10°C, the cooling gradient of the feed liquid is 0.5~2°C/h, and the cooling area of the cooling system is 4~6m ² /m ³ ;

The above-mentioned degree of saturation is preferably 1.1 to 1.2;

In the above-mentioned crystallization process, the pH is preferably controlled at 3.7 to 4.3;

The cooling gradient of the above feed liquid is preferably 0.5 to 1.5;

g separation, drying

Separation with a centrifugal separator, and then drying the crystalline fructose by airflow drying method, during the drying process, the temperature is controlled between 55°C and 60°C, and the time is 2 to 5 minutes, so that the water content of fructose is less than 0.1%;

Adopt the energy consumption of the unit product of the method of the present invention to reduce, and overcome the defect that fructose crystallization is difficult under the prior art, by controlling the parameter of simulated moving bed, can obtain high-purity fructose aqueous solution; The crystallization parameter that the present invention chooses all has Conducive to the crystallization of fructose.

Detailed ways:

Example 1

Technical scheme of the present invention comprises the steps of following sequence:

a. Corn is used as raw material, soaked, degermed, finely ground, sieved to remove fiber and protein, and then washed many times to obtain refined starch milk;

b. Continuous jet liquefaction, saccharification and other processes are used to obtain saccharified liquid from refined starch milk, and the obtained saccharified liquid is evaporated and concentrated into glucose concentrate by multi-effect falling film evaporator;

c Partially convert the glucose in the glucose concentrate into fructose through the isomerization reaction:

Pass the concentrated glucose solution through the immobilized isomerase column to obtain F 42 fructose syrup. The parameters controlled in the isomerization process are: feed sugar solution dry matter at 45%, purity 95%, pH7.8, isomerization The temperature is 60°C, the isomerization time is 3 hours, and the calcium ion is controlled to be less than 1ppm. During the isomerization process, magnesium sulfate is added to make the magnesium ion content greater than 36ppm as an activator for isomerase;

d. Separate the above-mentioned F42 fructose syrup by chromatographic separation to obtain a high-purity fructose aqueous solution;

Use simulated moving bed for chromatographic adsorption separation to achieve the purpose of separating fructose and glucose; simulated moving bed, wherein the parameters of chromatographic separation control are: feed total sugar concentration 0.3g/mL, feed flow rate: 25mL/min; After the feed liquid is full, open the flushing valve, the flushing liquid flow rate: 90mL/min; during the flushing process, the liquid phase flow rate in the bed: 3mL/min, and the liquid flow rate is controlled at 3.5mL/min; during the separation process, attention must be paid to the temperature Change, low temperature can not achieve the effect of separation, high temperature is not easy to operate, the temperature is generally controlled between 67 ℃;

After the separation operation of the simulated moving bed, the fructose content in the obtained product reaches more than 90%, which is refined and concentrated into a high-purity fructose aqueous solution for the production of crystalline fructose;

e evaporation concentration

First, use a multi-effect falling film evaporator to evaporate and concentrate the high-purity fructose aqueous solution obtained from the above separation to 75% of dry matter. The multi-effect falling film evaporator can use a five-effect falling film evaporator or a four-effect falling film evaporator;

Then continue to evaporate the dry matter to 95% with a vacuum scraper evaporator;

crystallization

Pass the above-mentioned concentrated fructose concentrate through a crystallizer to stir and cool it. During the crystallization process, the seed crystal dosage is 10%, and the crystallization time is 26 hours. The temperature difference between the cooling unit and the feed liquid is less than 10°C, the cooling gradient of the feed liquid is 1.0°C/h, and the cooling area of the cooling system is 6m ² /m ³ ;

g separation, drying

The crystalline fructose is separated by a centrifuge, and then dried by an airflow drying method. During the drying process, the temperature is controlled at about 56°C, and the time is 3m, so that the water content of the fructose is less than 0.1%.

Example 2

Technical scheme of the present invention comprises the steps of following sequence:

a. Corn is used as raw material, soaked, degermed, finely ground, sieved to remove fiber and protein, and then washed many times to obtain refined starch milk;

b. Continuous jet liquefaction, saccharification and other processes are used to obtain saccharified liquid from refined starch milk, and the obtained saccharified liquid is evaporated and concentrated into glucose concentrate by multi-effect falling film evaporator;

c Partially convert the glucose in the glucose concentrate into fructose through the isomerization reaction:

Pass the concentrated glucose solution through the immobilized isomerase column to obtain F 42 type fructose syrup. The parameters controlled in the isomerization process are: feed sugar solution dry matter at 40%, purity 94%, pH7.5, isomerization The temperature is 55°C, the isomerization time is 0.6h, and the calcium ion is controlled to be less than 1ppm. During the isomerization process, magnesium sulfate is added to make the magnesium ion content greater than 36ppm as an activator for isomerase;

D above-mentioned F 42 type fructose syrup is separated by chromatographic separation, obtains high-purity fructose aqueous solution;

Using simulated moving bed for chromatographic adsorption separation to achieve the purpose of separating fructose and glucose; multiple simulated moving beds, in which the parameters of chromatographic separation control are: total sugar concentration of feed: 0.2g/mL, feed flow: 9mL/min; When the feed liquid is full, open the flushing valve, the flow rate of the flushing liquid: 60mL/min; during the flushing process, the liquid phase flow rate in the bed: 2mL/min, and the liquid flow rate is controlled at 3mL/min; during the separation process, attention must be paid to the temperature Changes, low temperature can not achieve the effect of separation, high temperature is not easy to operate, the temperature is generally controlled at about 66 ° C;

After the separation operation of the simulated moving bed, the fructose content in the obtained product reaches more than 90%, which is refined and concentrated into a high-purity fructose aqueous solution for the production of crystalline fructose;

e evaporation concentration

First, use a multi-effect falling film evaporator to evaporate and concentrate the high-purity fructose aqueous solution obtained from the above separation to 75% of dry matter. The multi-effect falling film evaporator can use a five-effect falling film evaporator or a four-effect falling film evaporator;

Then continue to evaporate the dry matter to 90% with a vacuum scraper evaporator;

crystallization

Pass the above-mentioned concentrated fructose concentrate through a crystallizer to stir and cool it. During the crystallization process, the seed crystal dosage is 9%, the crystallization time is 30h, and the pH is controlled at 3.8 during the crystallization process. The temperature difference between the cooling unit and the feed liquid is less than 10°C, the cooling gradient of the feed liquid is 1.5°C/h, and the cooling area of the cooling system is 6m ² /m ³ ;

g separation, drying

The crystalline fructose is separated by a centrifuge, and then dried by an airflow drying method. During the drying process, the temperature is controlled at about 56°C, and the time is 3m, so that the water content of the fructose is less than 0.1%.

Example 3

Technical scheme of the present invention comprises the steps of following order:

a. Corn is used as raw material, soaked, degermed, finely ground, sieved to remove fiber and protein, and then washed many times to obtain refined starch milk;

b. Continuous jet liquefaction, saccharification and other processes are used to obtain saccharified liquid from refined starch milk, and the obtained saccharified liquid is evaporated and concentrated into glucose concentrate by multi-effect falling film evaporator;

c Partially convert the glucose in the glucose concentrate into fructose through the isomerization reaction:

Pass the concentrated glucose solution through an immobilized isomerase column to obtain F 42 fructose syrup. The parameters controlled in the isomerization process are: feed sugar solution dry matter at 50%, purity 95%, pH78.2, isomerization The temperature is 62°C, the isomerization time is 4 hours, and the calcium ion is controlled to be less than 1ppm. Magnesium sulfate is added during the isomerization process to make the magnesium ion content greater than 36ppm as an activator for isomerase;

D above-mentioned F 42 type fructose syrup is separated by chromatographic separation, obtains high-purity fructose aqueous solution;

Using a simulated moving bed for chromatographic adsorption separation to achieve the purpose of separating fructose and glucose; simulated moving bed, wherein the parameters of chromatographic separation control are: the total sugar concentration of the feed is 0.45g/mL, and the feed flow: 38mL/min; After the feed liquid is full, open the flushing valve, the flushing liquid flow rate: 110mL/min; during the flushing process, the liquid phase flow rate in the bed: 5mL/min, and the liquid flow rate is controlled at 4mL/min; during the separation process, we must pay attention to the temperature change , low temperature can not achieve the effect of separation, high temperature is not easy to operate, the temperature is generally controlled between 70 ℃;

After the separation operation of the simulated moving bed, the fructose content in the obtained product reaches more than 90%, which is refined and concentrated into a high-purity fructose aqueous solution for the production of crystalline fructose;

e evaporation concentration

First, use a multi-effect falling film evaporator to evaporate and concentrate the high-purity fructose aqueous solution obtained from the above separation to 75% of dry matter. The multi-effect falling film evaporator can use a five-effect falling film evaporator or a four-effect falling film evaporator;

Then continue to evaporate the dry matter to 95% with a vacuum scraper evaporator;

crystallization

Pass the above-mentioned concentrated fructose concentrate through a crystallizer for stirring and cooling. During the crystallization process, the seed crystal dosage is 12%, and the crystallization time is 25 hours. The temperature difference between the cooling unit and the feed liquid is less than 10°C, the cooling gradient of the feed liquid is 1.5°C/h, and the cooling area of the cooling system is 5m ² /m ³ ;

g separation, drying

The crystalline fructose is separated by a centrifuge, and then dried by an airflow drying method. During the drying process, the temperature is controlled at about 56°C, and the time is 3m, so that the water content of the fructose is less than 0.1%.

Claims (7)

1. W-Gum is produced the method for crystal diabetin, it is characterized in that, comprises the step of following order:

A is that raw material obtains starch milk with the corn;

B is with starch milk simmer down to glucose concentrated solution;

C partly is converted into fructose with the glucose in the glucose concentrated solution by isomerization reaction, obtains high fructose syrup;

D adopts the simulation moving-bed chromatographic adsorption that carries out to separate the high fructose syrup of above-mentioned gains, obtains highly purified fructose water solution;

The e evaporation concentration at first adopts the multiple-effect falling film vaporizer that above-mentioned separation is obtained high purity fructose water solution, and evaporation concentration arrives dry 70～75%, and then continues to steam dry between to 90% to 95% with the vacuum scraper evaporator;

The f Crystallization Procedure, the above-mentioned fructose concentrated solution well that concentrates is passed through crystallizer, crystal seed injected volume 8～12% in its crystallisation process, crystallization time 25～30h, PH be 3.5～5.0,45～65 ℃ of temperature, degree of supersaturation 1.1～1.25, the cooling unit of crystallizer and the feed liquid temperature difference are less than 10 ℃, and the cooling gradient of feed liquid is 0.5～2 ℃/h, cooling system cooling area 4～6m ²/ m ³

G reaches fructose moisture less than 0.1% by separating centrifuge separation, drying.

2. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, it is characterized in that saturation ratio described in the step f is 1.1～1.2.

3. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, it is characterized in that controlling PH in the crystallisation process described in the step f is 3.7～4.3.

4. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, and the cooling gradient that it is characterized in that feed liquid described in the step f is 0.5～1.5.

5. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, the parameter that it is characterized in that immobilized isomerase post control in its isomerization process of step c is: charging sugar soln dry is 40%～50%, purity 94%～96%, PH7.5～8.2,55～65 ℃ of isomerisation temperature, isomerization time 0.5～4h.

6. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, it is characterized in that the parameter of simulation moving-bed control in the steps d is: charging total sugar concentration 0.10～0.45g/mL; Feed rate 8～40mL/min; Washing fluid flow 60～120mL/min; Liquid phase flow rate 2～5mL/min in the bed in the flushing process; The fluid flow rate control is at 3～4mL/min; Between 65 ℃～70 ℃ of the temperature.

7. W-Gum as claimed in claim 1 is produced the method for crystal diabetin, it is characterized in that the multiple-effect falling film vaporizer adopts five to imitate falling-film evaporator or quadruple effect falling-film evaporator among the step e.