TECHNOLOGY FOR EXTRACTING AND PREPARING HIGH-PURITY RAFFINOSE FROM DEFATTED WHEAT GERM

Abstract

The present invention discloses a process for preparing high-purity raffinose from defatted wheat germ comprising the steps of percolate extraction of raffinose from defatted wheat germ, decoloration by extraction from the abstraction liquid, electrodialysis desalination, impurity removal by simulated moving bed, concentration and crystallization, with the absolute purity of raffinose as high as 98% and the recovery up to 75%. The process is not only reliable and easy to operate, but also easy to realize industrial production and control the parameters.

Claims

1. A process for preparing high-purity raffinose from defatted wheat germ, the method comprising the follows steps: (1) conducting percolation extraction of the defatted wheat germ, and collecting percolate containing raffinose; (2) concentrating percolate of Step (1) to remove alcohol, dissolving solid substance followed by filtering to insoluble substance, extracting the filtrate with an organic solvent and concentrating the aqueous phase, obtaining a decolored solution; (3) processing the decolored solution of Step (2) with a microporous membrane of a drainage, diluting the solution with water to obtain a pretreatment liquid with 50150 mg/mL solid concentration, and desalinating the pretreatment liquid with electrodialysis to obtain a desalination solution; (4) separating the desalination solution of Step (3) with a simulated moving bed, and collecting flow containing raffinose, obtaining a supersaturated syrup by concentrating; and (5) crystallizing the supersaturated syrup and obtaining white crystallization raffinose after drying.

2. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 1, characterized in that the volume of solution with dissolving solid substance of step (2) is 20%35% of the percolate volume.

3. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 1, characterized in that organic solvent of Step (2) is n-butanol, iso-butanol, ethyl acetate, n-hexane and petroleum ether, and the volume is 0.51.5 times the number of filtrate volume.

4. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 1, characterized in that the electrodialysis desalination process of Step (3) comprises the steps of: the pretreatment liquid and pure water are taken as concentrated and dilute phase, with taking Na.sub.2SO.sub.4 as polar water; the pretreatment liquid, and pure water and polar water are cycled in the instrument; desalinating for 23 hours under constant voltage and velocity.

5. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 4, characterized in that the mass concentration of Na.sub.2SO.sub.4 of Step (3) is 3%8% and the volume ratio of the polar water, the pretreatment liquid and pure water is 0.25:1:(13).

6. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 4, characterized in that the desalination conditions: operating voltage is 1530 V and the liquid flow rate is 1030 L/h.

7. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 1, characterized in that the simulated moving bed equipment has four areas, containing 24 chromatogram column in each area, the fixed-bed adsorbent of chromatographic column is extreme acidic (Ca) ion exchange resin or (Na) ion exchange resin, with water as an eluent.

8. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 7, characterized in that crosslinking degree of an adsorbent is 2%8% and the size is 100400 mesh.

9. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 7, characterized in that the separate operation of the simulated moving bed equipment: the switching time is 3090 seconds, velocities of flow in area I, area II, area III and area IV are 0.670.86, 0.440.70, 0.470.79 and 0.410.60, respectively.

10. The process for preparing high-purity raffinose from defatted wheat germ, according to claim 1, characterized in that isothermal operation is used in the simulated moving bed equipment and the column temperature is 6080 C.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0043] FIG. 1 HPLC chromatogram of product raffinose of the present invention

[0044] FIG. 2 HPLC chromatogram of product sucrose of the present invention

[0045] FIG. 3 Sketch of simulated moving bed equipment with four areas

DETAILED DESCRIPTION OF THE INVENTION

[0046] The present invention is described in reference to the following specific embodiments, basing on the preparation methods and test results of high-purity raffinose.

Embodiment 1

[0047] (1) 200 g defatted wheat germ (wherein raffinose is 4.6% by mass) was packed in diacolation column ( 4.050 cm) by wet method. The accumulation volume is about 500 mL after loading evenly. The defatted wheat germ is immersed for 30 min and under constant temperature of 60 C., and full swelling of defatted wheat germ.

[0048] The 80% aqueous ethanol was added from top of adsorption column continuously after opening the outlet valve of diacolation column. The flow rate was controlled at 1820 mL/min, until the collected percolate volume of 1371 mL.

[0049] 230 g defatted wheat germ was packed in diacolation column by the wet method. The accumulation volume is about 592 mL. Other conditions are as above with the collected percolate volume of 1948 mL.

[0050] 150 g defatted wheat germ was packed in diacolation column by the wet method. The accumulation volume is about 355 mL. Other conditions are as above with the collected percolate volume of 1066 mL.

[0051] The percolates were combined, and used as a raw material liquid for subsequent operations. The solids concentration is 28.6 mg/mL after analysis, with purity of raffinose as 20.8% and the yield as 97.8%. (26 g raffinose)

(2) The 500 mL percolate was concentrated to thick status, and then added deionized water, to ensure that the total volume is less than 150 mL. The filtrate was diluted to 150 mL after filtered by cloth and membrane successively. 135 mL solution is extracted by equal numbers of n-butanol. With analysis of aqueous phase after extraction, the purity of raffinose is 28.9%, the solid concentration is 98.6 mg/mL, and the recovery of raffinose is 92%.

[0052] Aqueous phase was concentrated to remove alcohol. The solid concentration of 100 mg/mL is prepared by adding deionized water.

(3) Desalination: the decoloring solution was handled with 0.45 m microporous membrane of the drainage before adding electrodialysis with 5 wt % Na.sub.2SO.sub.4 as polar water. The electrodialysis conditions: voltage is 25 V, the flow of material was 20 L/h. The preferred volume ratio of polar water, the liquor, and pure water is 0.25:1:1. The electrical conductivity of desalting chamber was decreased from 979 S/cm to 85.7 S/cm after desalination for 2 hours. 481 mL liquor was collected containing 19.51 g arabinose, with purity up to 60%. And desalination rate was as high as 91% and the recovery of this step was 95%.
(4) SMB (simulated moving bed) adsorption: simulated moving bed equipment is composed of eight stainless (25 cm*0.46 cm) steel columns in series with packing with extreme (Na) ion exchange resin of 200400 mesh, 2% crosslinking degree. The desalted solution was added in simulated moving bed equipment from feed inlet with flow rate of 0.1 mL/min. The flow rate in every area is 0.75 in area I, 0.47 in area II, 0.51 in area III and 0.5 in area IV. The switching time is 60 seconds, and the separation temperature is 60 C. The raffinate containing raffinose was obtained from residue exit. After analysis by HPLC, the purity of raffinose is 93%, the solid concentration is 98.6 mg/mL, and the recovery of raffinose is 93%.
(5) Crystallization: the effluent was distillated reduced pressure to syrup before adding 85% ethanol solution, and with solid to liquid ratio was 1:6. The solution was refluxed for 20 minutes in a water bath of 90 C., and then cooled down to room temperature with adding a small amount of raffinose. The solution stayed in the refrigerator of 5 C. for 24 hours. The crystal was filtered and washed with little absolute ethanol. The product was dried in a vacuum oven at 30 C. for 6 hours. 2.02 g raffinose can be gotten with purity as 98.5%. The recovery of raffinose in whole process was 68% basing on the mass of raffinose in defatted wheat germ.
Mother liquor after crystallization could be cycled in the step of adsorption separation, so recovery was improved to 79.5% basing on recovery of crystallization as 100%.

Embodiment 2

[0053] The 500 mL extract of Step (1) was handled as the same operation of Step (2). The purity of raffinose is 28.7%, the solid concentration is 100.7 mg/mL.
(3) 5 wt % Na.sub.2SO.sub.4 was used as polar water. The electrodialysis conditions: voltage is 25 V, the flow of material was 15 L/h. The electrical conductivity of desalting chamber was decreased from 992 S/cm to 108 S/cm after desalination for 2.5 hours.
(4) SMB (simulated moving bed) adsorption: simulated moving bed equipment is composed of eight stainless steel columns (25 cm*0.46 cm) in series with packing with extreme (Na) ion exchange resin of 200400 mesh, 4% crosslinking degree. The desalted solution was added in simulated moving bed equipment from feed inlet with flow rate of 0.1 mL/min. The flow rate in every area is 0.75 in area I, 0.47 in area II, 0.51 in area III and 0.5 in area IV. The switching time is 60 seconds, and the separation temperature is 60 C. The raffinate containing raffinose was obtained from residue exit. After analysis by HPLC, the purity of raffinose is 92%, and the recovery of raffinose is 91%.
(5) Crystallization is added 85% ethanol solution for 12 hours, with solid to liquid ratio was 1:8. 1.94 g raffinose can be gotten with purity as 98.5%. The recovery of raffinose in whole process was 65.4% basing on the mass of raffinose in defatted wheat germ. Mother liquor after crystallization could be cycled in the step of adsorption separation, so recovery was improved to 76.1% basing on recovery of crystallization as 100%.

Embodiment 3

[0054] The operation of Step (1) and Step (2) is the same as Embodiment 1.
(3) 5 wt % Na.sub.2SO.sub.4 was used as polar water. The electrodialysis conditions: voltage is 25 V, the flow of material was 15 L/h. The electrical conductivity of desalting chamber was decreased from 1017 S/cm to 115 S/cm after desalination for 2.5 hours.
(4) SMB (simulated moving bed) adsorption: simulated moving bed equipment is composed of eight stainless steel columns (25 cm*0.46 cm) in series with packing with extreme (Ca) ion exchange resin of 200400 mesh, 2% crosslinking degree. The desalted solution was added in simulated moving bed equipment from feed inlet with flow rate of 0.1 mL/min. The flow rate in every area is 0.75 in area I, 0.47 in area II, 0.51 in area III and 0.5 in area IV. The switching time is 60 s, and the separation
temperature is 65 C. The raffinate containing raffinose was obtained from residue exit. After analysis by HPLC, the purity of raffinose is 91%, and the recovery of raffinose is 92%.
(5) Crystallization is added 80% methanol solution for 24 hours, with solid to liquid ratio was 1:8. 1.92 g raffinose can be gotten with purity as 98.2%. The recovery of raffinose in whole process was 64.7% basing on the mass of raffinose in defatted wheat germ. Mother liquor after crystallization could be cycled in the step of adsorption separation, so recovery was improved to 77% basing on recovery of crystallization as 100%.

Embodiment 4

[0055] The operation of Step (1), Step (2), Step (3) and Step (4) is the same as Embodiment 3.
(5) Crystallization is added 85% methanol solution for 24 h, with solid to liquid ratio was 1:8. 1.98 g raffinose can be gotten with purity as 98.5%. The recovery of raffinose in whole process was 67% basing on the mass of raffinose in defatted wheat germ. Mother liquor after crystallization could be cycled in the step of adsorption separation, so recovery was improved to 78% basing on recovery of crystallization as 100%.

Measurement Methods of Concentration of Raffinose and Sucrose

[0056] The concentration of raffinose and sucrose is measured by the following way in the above embodiment.
The analysis method of UHPLC is established by ultra performance liquid chromatograph of DIONEX D3000 and detector is corona charged aerosol detection (CAD). Chromatographic column: GRACE Prevail Carbohydrate ES (250 mm4.6 mm, 5 m); the liquid volume: 5 L; mobile phase: acetonitrile-water (80:20, v/v); flow velocity: 1 mL/min; column temperature: 30 C.
The concentration range of the monosaccharides:
Raffinose: 16 g/L; sucrose: 16 g/L
The standard curve of the monosaccharides:
Raffinose: y=2.1553*10.sup.4x.sub.2+0.02045x; sucrose: y=4.01*10.sup.4x.sup.2+0.01483x. Xpeak area, yconcentration.
Testing confirms that the retention times of raffinose and sucrose are 8.73 min (FIG. 1) and 6.22 min (FIG. 2), respectively.

[0057] The above embodiment are optimization of the present invention. To traditional technician, the improvement and polish also belong to the scope of protection of the invention, which base on the technology principle of the present invention.