METHOD FOR PREPARING ORYZANOL FROM ORYZANOL-CONTAINING SOAPSTOCK SERVING AS RAW MATERIAL

Abstract

A method for preparing oryzanol from oryzanol-containing soapstock as a raw material includes the following steps: 1) alkali-alcohol thermal dissolution; 2) heat-preserved fine filtration; 3) heat-preserved ultrafiltration membrane separation; 4) heat-preserved decolorization; 5) acid neutralization and filtration; 6) washing; and 7) drying. The temperatures of the step 1) to the step 4) are controlled at 50-60° C. The method has a heat preservation operation at 50-60° C., membrane separation, decolorization and washing, to finally prepare a white powdered product. The purity of product oryzanol is greater than 98% and the yield is greater than 73%. The method does not use toxic or combustible or explosive organic solvents such as methanol, ether, hexane and solvent oil, so that the product use safety is improved; the production process is simple, has low requirements on production equipment, is easy to operate and realize, and is low in production cost and suitable for industrial production.

Claims

1. A method for preparing oryzanol from oryzanol-containing soapstock serving as a raw material, comprising the following steps: 1), alkali-alcohol thermal dissolution: adding ethanol into the raw material, heating to 50-60° C., adjusting the system to alkalescence, and dissolving the raw material to obtain a solution; 2), heat-preserved fine filtration: maintaining the temperature in the step 1), and using a precision filter to filter the solution; 3), heat-preserved ultrafiltration membrane separation: carrying out membrane separation on the filtrate by a high temperature resistant ultrafiltration membrane under a condition of 50-60° C., and collecting membrane separation liquid in a molecular weight range of 1000-5000; 4), heat-preserved decolorization: adding an inorganic decolorizer into the membrane separation liquid, and fully stirring and filtering the liquid to obtain decolorized liquid; 5), acid neutralization and filtration: neutralizing the decolorized liquid with dilute acid, cooling the liquid, standing the liquid to completely separate out precipitates, carrying out centrifugation, and collecting the centrifugated precipitates; 6), washing: adding ethyl acetate, high-concentration ethanol and warm water in sequence into the centrifugated precipitates for washing, wherein the washing is to add a washing liquid of the above solvent or solution into the centrifugated precipitates, stir and mix the product thoroughly, and centrifugate the mixture to obtain centrifugated precipitates for next step of washing; and 7), drying: drying the precipitates to obtain a finished oryzanol product.

2. The method according to claim 1, wherein the system in the step 1) to the step 4) is maintained at a temperature of 50-60° C.

3. The method according to claim 1, wherein at the step 1), the ethanol refers to ethanol at a concentration greater than 80%, preferably ethanol at a concentration greater than 85%, and more preferably, ethanol at a concentration greater than 85% is used; the adding amount of the ethanol is 5-10 times the weight of an oryzanol-containing soap base; the heating refers to heating till the temperature is 50-60° C.; the adjustment to alkalescence refers to use of an alkaline hydroxide, such as sodium hydroxide, and the hydroxide to adjust the pH to 8.5-9.5.

4. The method according to claim 1, wherein at the step 2), the filtration temperature is controlled at 50° C.-60° C.; for filtration, a precision filter with a folding filter element is used; the filter element has a pore size of 0.45 μm and an operating pressure of 0.2-0.4 MPa.

5. The method according to claim 1, wherein at the step 3), the high temperature resistant ultrafiltration membrane is made of polyether sulfone, and is capable of withstanding a temperature of 80° C.

6. The method according to claim 1, wherein at the step 3), the molecular weight cut-off of the membrane is set to be 1000-5000, and a membrane operating pressure is 1.0-2.0 MPa.

7. The method according to claim 6, wherein the order of the membrane separation is: firstly, the solution is filtered with an ultrafiltration membrane with a molecular weight cut-off of 5000; membrane downstream liquid, i.e., permeated liquid, is then collected; the permeated liquid is filtered with an ultrafiltration membrane with a molecular weight cut-off of 1000; and membrane upstream liquid, i.e., cut-off liquid, is collected.

8. The method according to claim 1, wherein at the step 4), the decolorizer is at least one of activated clay and activated carbon, and the adding amount of the decolorizer is 3-6% of the weight of the oryzanol-containing soapstock raw material; and preferably, the decolorizer is a compound of activated clay and activated carbon according to a mass ratio of 1-2:1-2.

9. The method according to claim 1, wherein at the step 6), in the washing step using the high-concentration ethanol and/or warm water, 50-70% high-concentration ethanol/or warm water is added to the centrifugated precipitates of the previous step, and is fully stirred, uniformly mixed and centrifugated; and the remaining high-concentration ethanol/or warm water is added into a centrifuge in batches.

10. The method according to claim 1, wherein the mass of the centrifugated precipitates and the volume of the washing liquid, i.e., the ethyl acetate, the high-concentration ethanol and the warm water, at the step 6) are in accordance with a mass-volume ratio (kg/L) of 1-2:2-5:2-5:3-6, preferably, the mass of the centrifugated precipitates and the volumes of the ethyl acetate, the high-concentration ethanol and the warm water are in accordance with a mass-volume ratio (kg/L) of 1-1.3:2-3:3-4:3.5-5.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The method of an extraction process of the present disclosure will be further described below in combination with embodiments.

[0055] A raw material used in the embodiment of the present disclosure is oryzanol-containing soapstock which is purchased from Hunan Dongxiang Oil Co., Ltd., and the content of oryzanol is 13.65%. The purity of edible ethanol used in the embodiment of the present disclosure is 95%, and the edible ethanol is diluted with deionized water to a required concentration when needed; and the purity of ethyl acetate is 99.5% (food grade). Chemical reagents and raw and auxiliary materials used in the embodiment of the present disclosure are all obtained through conventional commercial channels, unless otherwise specified.

[0056] The content of oryzanol in a product is detected by ultraviolet-visible spectroscopic absorption chromatography (UV).

Embodiment 1

[0057] 1. Alkali-alcohol thermal dissolution: 2000 L of edible ethanol at a concentration of 89% is first added into a 6 m.sup.3 extraction tank, and the tank is turned on for stirring; 600 kg of oryzanol-containing soapstock is fed into the extraction tank in constant stirring; and 2200 L of edible ethanol at the concentration of 89% is continued to be added. A cover is closed to continuously carry out stirring; cooling water is turned on, and steam is fed for heating. When the temperature is 54° C., 4wt % of a sodium hydroxide aqueous solution metered is added into the extraction tank to adjust the pH of the system to be 9.0. A sample is taken to observe dissolution of the solution; the raw material is completely dissolved after 20 min, and a few of oil residues remain; and 4500 L of solution is obtained.

[0058] 2. Heat-preserved fine filtration: the temperature is maintained at 54° C.; a precision filter with a folding filter element having a pore size of 0.45 um is configured; the solution is filtered by the precision filter; an operating pressure is maintained at 0.3 MPa, and a clear filtrate is obtained.

[0059] 3. Heat-preserved ultrafiltration membrane separation: the temperature is maintained at 54° C.; two groups of ultrafiltration membrane tubes are pre-assembled with high temperature resistant membranes (GE membranes of Duratherm HWS UF series) which are made of polyether sulfone and can withstand the highest temperature of 70° C., and respectively have molecular weight cut-off of 5000 (FLD-UF001) and 1000 (FLD-UF005); a membrane operating pressure is maintained at 1.5 MPa; the solution is firstly filtered with the ultrafiltration membrane with the molecular weight cut-off of 5000, and membrane downstream liquid is then collected; 100 L of edible ethanol at the concentration of 89% is added to clean membrane residues, and feeding permeated liquid and cleaning permeated liquid are combined to obtain permeated liquid; the permeated liquid is filtered with the ultrafiltration membrane with the molecular weight cut-off of 1000, and membrane upstream liquid is collected; 4550 L of cut-off liquid is obtained, i.e., membrane separation liquid.

[0060] 4. Heat-preserved decolorization: the temperature is maintained at 54° C.; 32 kg of activated clay and 32 kg of activated carbon are added into the membrane separation liquid for full stirring for 20 min; a plate and a frame are matched with 1000-mesh canvas filter cloth for filtration to obtain light yellow clear and transparent decolorized liquid.

[0061] 5. Acid neutralization and filtration: under constant stirring, the pH of the decolorized liquid is adjusted to 7.0 with dilute sulphuric acid at a concentration of 6%, and stirring is stopped; running water is fed for cooling; standing is carried out for 8 h to cause precipitates to be completely precipitated; the precipitates are centrifugated through a three-foot cloth bag; centrifugated precipitates are collected; and 204 kg of wet centrifugated precipitates are obtained.

[0062] 6: Washing: 500 L of ethyl acetate is added into the centrifugated precipitates for full stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and then centrifugated precipitates are collected; 600 L of edible ethanol at the concentration of 89% is added into the precipitates for fully stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag; the edible ethanol at the concentration of 89% is added into a centrifuge twice, 50 L at each time, for full permeation and precipitation, and centrifugated precipitates are collected; 600 L of purified water at a temperature of 40° C. is added into the precipitates for full stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and the purified water at the temperature of 40° C. is added into the centrifuge for three times, 50 L at each time, for full permeation and precipitation; and centrifugated precipitates are collected.

[0063] 7. Drying: the precipitates are vacuum-dried with microwaves, and the drying temperature is controlled at 62° C. to obtain 63.26 kg of a finished oryzanol product.

[0064] After testing, the content of the finished oryzanol product is 99.12%, and the product yield is 76.56%.

Embodiment 2

[0065] 1. Alkali-alcohol thermal dissolution: 1000 L of edible ethanol at a concentration of 92% is first added into a 3 m.sup.3 extraction tank, and the tank is turned on for stirring; 250 kg of oryzanol-containing soapstock is fed into the extraction tank in constant stirring; and 1000 L of edible ethanol at the concentration of 92% is continued to be added. A cover is closed to continuously carry out stirring; cooling water is turned on, and steam is fed for heating. When the temperature is 52° C., 6% of a sodium hydroxide aqueous solution metered is added into the extraction tank to adjust the pH of the system to be 9.3. A sample is taken to observe dissolution of the solution; the raw material is completely dissolved after 15 min, and a few of oil residues remain; and 2100 L of solution is obtained.

[0066] 2. Heat-preserved fine filtration: the temperature is maintained at 52° C.; a precision filter with a folding filter element having a pore size of 0.45 um is configured; the solution is filtered by the precision filter; an operating pressure is maintained at 0.25 MPa, and a clear filtrate is obtained.

[0067] 3. Heat-preserved ultrafiltration membrane separation: the temperature is maintained at 52° C.; two groups of ultrafiltration membrane tubes are pre-assembled with imported high temperature resistant membranes which are made of polyether sulfone and can withstand the highest temperature of 70° C., and respectively have molecular weight cut-off of 5000 and 1000; a membrane operating pressure is maintained at 1.7 MPa; the solution is firstly filtered with the ultrafiltration membrane with the molecular weight cut-off of 5000, and membrane downstream liquid is then collected; 100 L of edible ethanol at the concentration of 92% is added to clean membrane residues, and feeding permeated liquid and cleaning permeated liquid are combined to obtain permeated liquid; the permeated liquid is filtered with the ultrafiltration membrane with the molecular weight cut-off of 1000, and membrane upstream liquid is collected; 2150 L of cut-off liquid is obtained, i.e., membrane separation liquid.

[0068] 4. Heat-preserved decolorization with an inorganic decolorizer: the temperature is maintained at 52° C.; 20 kg of activated clay and 10 kg of activated carbon are added into the membrane separation liquid for full stirring for 20 min; a plate and a frame are matched with 1000-mesh canvas filter cloth for filtration to obtain light yellow clear and transparent decolorized liquid.

[0069] 5. Acid neutralization and filtration: under constant stirring, the pH of the decolorized liquid is adjusted to 7.2 with dilute hydrochloric acid at a concentration of 9%, and stirring is stopped; running water is fed for cooling; standing is carried out for 10 h to cause precipitates to be completely precipitated; the precipitates are centrifugated through a three-foot cloth bag; centrifugated precipitates are collected; and 83 kg of wet centrifugated precipitates are obtained.

[0070] 6. Washing: 250 L of ethyl acetate is added into the centrifugated precipitates for full stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and then centrifugated precipitates are collected; 230 L of edible ethanol at the concentration of 92% is added into the precipitates for fully stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag; the edible ethanol at the concentration of 92% is added into a centrifuge twice, 50 L at each time, for full permeation and precipitation, and centrifugated precipitates are collected; 250 L of purified water at a temperature of 40° C. is added into the precipitates for full stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and the purified water at the temperature of 40° C. is added into the centrifuge for three times, 50 L at each time, for full permeation and precipitation; and centrifugated precipitates are collected.

[0071] 7. Drying: the precipitates are dried with blast air, and the drying temperature is controlled at 65° C. to obtain 25.70 kg of a finished oryzanol product which is white powder.

[0072] After testing, the content of the finished oryzanol product is 99.35%, and the product yield is 74.82%.

Embodiment 3

[0073] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 50° C. throughout the whole process at the step 1) to the step 4). 60.81 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 99.04%, and the product yield is 73.53%.

Embodiment 4

[0074] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 56° C. throughout the whole process at the step 1) to the step 4). 62.11 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 99.26%, and the product yield is 75.28%.

Embodiment 5

[0075] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 60° C. throughout the whole process at the step 1) to the step 4). 61.53 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 99.18%, and the product yield is 74.51%.

Embodiment 6

[0076] Other steps are the same as those in Embodiment 1, and a difference is that the decolorizer at the step 4) only uses 64 kg of activated clay. 61.18 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 98.67%, and the product yield is 73.71%.

Embodiment 7

[0077] Other steps are the same as those in Embodiment 1, and a difference is that the decolorizer at the step 4) only uses 64 kg of activated carbon. 61.90 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 98.25%, and the product yield is 74.26%.

Embodiment 8

[0078] Other steps are the same as those in Embodiment 1, and a difference is that at the step 3), the solution is firstly filtered with the ultrafiltration membrane with the molecular weight cut-off of 1000, and then the membrane downstream liquid is collected; 100 L of edible ethanol at the concentration of 92% is added to clean membrane residues, and feeding permeated liquid and cleaning permeated liquid are combined to obtain permeated liquid; and the permeated liquid is then filtered with the ultrafiltration membrane with the molecular weight cut-off of 5000. 61.09 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 98.14%, and the product yield is 73.20%.

Comparative Example 1

[0079] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 46° C. throughout the whole process at the step 1) to the step 4). 57.79 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 95.38%, and the product yield is 67.30%.

Comparative Example 2

[0080] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 43° C. throughout the whole process at the step 1) to the step 4). At the step 3), during heat-preserved ultrafiltration membrane separation, the membranes are blocked, and products cannot be effectively produced.

Comparative Example 3

[0081] Other steps are the same as those in Embodiment 1, and a difference is that the temperature of the system is controlled at 65° C. throughout the whole process at the step 1) to the step 4). 54.46kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 96.72%, and the product yield is 64.31%.

Comparative Example 4

[0082] Other steps are the same as those in Embodiment 1, and a difference is that at the step 6) of washing, the ethyl acetate is replaced by isoamyl alcohol. 61.94 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 95.84%, and the product yield is 72.48%.

Comparative Example 5

[0083] Other steps are the same as those in Embodiment 1, and a difference is that at the step 6) of washing, the washing order is changed: 500 L of ethyl acetate is added into the centrifugated precipitates for full stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and then centrifugated precipitates are collected; 600 L of purified water at the temperature of 40° C. is added into the precipitates for fully stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and the purified water at the temperature of 40° C. is added into a centrifuge for three times, 50 L at each time, for full permeation and precipitation; centrifugated precipitates are collected; 600 L of edible ethanol at the concentration of 89% is added into the precipitates for fully stirring and uniform mixing; the mixture is centrifugated through the three-foot cloth bag, and the edible ethanol at the concentration of 89% is added into the centrifuge for three times, 50 L at each time, for full permeation and precipitation; and centrifugated precipitates are collected. 61.75 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 96.38%, and the product yield is 72.67%.

Comparative Example 6

[0084] Other steps are the same as those in Embodiment 1, and a difference is that at the step 6) of washing, washing with the ethyl acetate is omitted, and ethanol and warm water are directly used for washing. 64.75 kg of a finished oryzanol product is finally obtained. After testing, the content of the finished oryzanol product is 91.36%, and the product yield is 72.23%.

[0085] The above detailed description is a specific description of one of the possible embodiments of the present disclosure. This embodiment is not intended to limit the patent scope of the present disclosure. Any equivalent implementation or modification that does not deviate from the present disclosure shall fall within the scope of the technical solution of the present disclosure.