CN1563106A - Preparing water soluble chitosan or in small molecular weight through radiation method - Google Patents
Preparing water soluble chitosan or in small molecular weight through radiation method Download PDFInfo
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- CN1563106A CN1563106A CN 200410010767 CN200410010767A CN1563106A CN 1563106 A CN1563106 A CN 1563106A CN 200410010767 CN200410010767 CN 200410010767 CN 200410010767 A CN200410010767 A CN 200410010767A CN 1563106 A CN1563106 A CN 1563106A
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Abstract
The invention belongs to a method for preparing small molecular weight or water-solubility chitosan by using radiation process. It is characterized by that a refined high molecular weight chitosan solid or solution can be irradiated by using 60 Co gamma-rays and degraded, and the degradation product is undergone the after-treatment steps of dissolution and decolouration, etc. so as to obtain the invented small molecular weight or water-solubility chitosan. Said chitosan has several purposes, can be used as agricultural production-increasing agent, food drying agent, natural anti-bacterial material and bio-medicine material, etc.
Description
Technical field
The present invention relates to use radiation method (
60The Co gamma-radiation) prepares the method for lower molecular weight water-insoluble or small molecular weight water-soluble chitosan.
Background technology
Chitosan is the deacetylation product of natural product chitin, and chemical structure is the polysaccharide that is formed by connecting with β-1,4 glycosidic link with 2-amino-2-deoxy-D-glucose.Contain active amino in the chitosan molecule, amino can positively charged, is unique natural alkaline polysaccharide.Have activity hydroxy again on the sugar ring, thereby chitosan have good wetting ability and water-retentivity again.In recent years, people have carried out extensive studies to chitosan character and function, find the important application of chitosan in industries such as agricultural, environment, food, biology, medical science, materials.
Low-molecular weight chitoglycan or oligosaccharide have tangible anti-microbial activity and water-retentivity, and the biological activity of inducing plant growth, can promote plant-growth, microbiostatic activity, absorb and maintenance moisture, so can be as the volume increase agent of agricultural, the antistaling and antiseptic agent of food or fruit, the coating material of crop seeds, the natural antibacterial agent of industry and daily living article.
Simultaneously, a large amount of both at home and abroad toxicology test proof chitosan or oligochitosan are nontoxic to human body, can directly contact with human body or be absorbed by the body.So the range of application of chitosan or oligosaccharide can expand to makeup, protective foods, medicine or enzyme carrier, burn dressing etc.
But through deacetylated and chitosan molecule amount that make is very high, can only be dissolved in acidic aqueous solution, thereby have limited its extensive utilization by chitin.In addition, the nature difference of the chitosan that molecular weight is different is very big, sometimes even show diametrically opposite characteristic, embody above listed performance fully, and the molecular weight of chitosan must be reduced to certain scope.
At present, the degradation method of reported chitosan is broadly divided into three classes: acid-hydrolysis method, oxidation style and enzyme liberating method.The acid degradation method makes the glycosidic link fracture with acidity (hydrochloric acid, phosphoric acid, hydrofluoric acid, acetate etc.) the solution heating of chitosan, generates low-molecular weight chitoglycan or further generates oligochitosan (as Chinese patent CN 1389477).Oxidation style makes the main chain oxidation scission of chitosan, makes the small molecular weight water-soluble chitosan, wherein mainly adopts hydrogen peroxide method (as Chinese patent CN 1283634).Hydrogen peroxide oxidation process is divided into three kinds of acid system, alkaline process (as Chinese patent CN 1318567) and neutral methods again, and promptly the medium of oxidizing reaction is respectively acid, alkalescence and neutral.So acid degradation method or oxidation style are often used concentrated acid or concentrated base, cause environmental pollution to a certain degree, should not advocate in today that environmental protection comes into one's own.The enzyme liberating method that occurs has the efficient height recently, the characteristics that environmental pollution is little, but the enzyme cost of degrading used is too high, relates to very complicated zymotechnique again, is unsuitable for cost is had the food and the agricultural use of strict demand.
Summary of the invention
The purpose of this invention is to provide the preparation method that a kind of radiation method prepares small molecular weight or water-soluble chitosan.
Present method is a starting raw material with the technical grade high molecular weight chitosan, through the purification of raw material, and radiation degradation, post-treating and other steps makes lower molecular weight water-insoluble or small molecular weight water-soluble chitosan.Accompanying drawing 1 has provided the technical process of present method, is summarized as follows:
The purification of raw material: the technical grade chitosan is fully dissolved with the excessive acetic acid aqueous solution, and acetic acid solution concentration is 0.5%～15.0%, gets 2.0%～10.0% better, improves acetic acid concentration, can reduce the consumption of acetic acid solution.The chitosan solution that dissolving is good is used earlier filtered through gauze, and filter with G2 glass sand core funnel the back, discards insolubles.Stir down the NaOH with 10%～20%, NaHCO
3Or NaOH and NaHCO
3Mixing solutions add in the filtrate, regulate pH to 7～8, fully after the vibration, filter with G1 glass sand core funnel, throw out is earlier with second distillation washing 1～3 time, and the back is with methyl alcohol, ethanol or washed with isopropyl alcohol 1～3 time, throw out at 20～50 ℃ of following vacuum dryings, is obtained the purified chitosan.
Chitosan radiation degradation: use
60The Co gamma-radiation carries out the irradiation-induced degradation of chitosan.The chitosan of radiation treatment can be solid or solution, can carry out irradiation under anaerobic or aerobic conditions, and the chitosan solid is carried out irradiation, and dosage is 50～300kGy, preferred 150～250kGy; The chitosan acidic solution is carried out irradiation, and dosage is 1～200kGy, preferred 40～150kGy; Chitosan acetate, hydrochloric acid or lactic acid/hydrogen peroxide uniform solution is carried out irradiation, dosage range 1～200kGy, preferred 5～100kGy; The non-uniform solution of chitosan/hydrogen peroxide is carried out irradiation, dosage range 1～200kGy, preferred 40～150kGy.
The aftertreatment of irradiation sample: stir down,
60The irradiated chitosan solution of Co gamma-radiation, the acid uniform solution of chitosan, chitosan acidity/hydrogen peroxide uniform solution in the non-uniform solution of chitosan/hydrogen peroxide, adds NaOH, KOH or NaHCO
3The aqueous solution, being neutralized to pH is 6～8, with 0.2～0.6M NaHCO
3It is better that solution is regulated pH to 6～7.G2 glass sand core funnel filters, and removes insolubles, adds an amount of 30% (w) superoxol in the filtrate, stirs, treat the filtrate color take off light after, concentrating under reduced pressure filtrate is to 10～50% of original volume.Stir and add methyl alcohol, the mixed solution of ethanol, acetone or alcohol and acetone, ethanol/acetone volume ratio: 1/9～9/1 down; Leave standstill, treat the abundant post precipitation of chitosan, filtration is desolvated, and with ethanol or washed with isopropyl alcohol 1～3 time, uses washing with acetone then, and vacuum-drying promptly gets water-soluble low molecular weight chitosan.Right
60The chitosan solid of Co gamma-radiation irradiation-induced degradation, with acetate, lactic acid or aqueous hydrochloric acid dissolving, G2 glass sand core funnel filters, and removes insolubles, adds the decolouring of 30% (w) superoxol in the filtrate earlier.All the other post-processing steps are the same.
The present invention selects seldom to use in the preparation of chitosan at present
60Co gamma-radiation irradiation chitosan solid or acidic solution prepare water-soluble chitosan.Compare with additive method, use irradiance method degraded macromolecular amount chitosan only to need a spot of acid, alkali, can not cause environmental pollution, also need not heating,, just can reach the purpose of degraded as long as at room temperature chitosan solid or solution are carried out irradiation.But radiation is convenient to realize the serialization and the industrialization of degradation of chitosan technology with cobalt source continuous operation.In the infrared spectra of chitosan radiation degradation front and back sample (seeing accompanying drawing 2), 3450 ~ 3200cm
-1The place is-the OH charateristic avsorption band 1575 ~ 1610cm
-1The place is-NH
2The angle vibration absorption peak, 1050 ~ 1070cm
-1The place is glycosidic link C-O stretching vibration absorption peak.Each characteristic peak intensity does not have considerable change in the accompanying drawing 4, the pyranose ring of the made chitosan of proof radiation degradation method is not damaged, radiation has just caused the fracture of chitosan molecule main chain, can infer that its biochemical function of chitosan that is made by radiation method and the chitosan of being produced by other method do not have difference.Simultaneously, X-ray diffraction (seeing accompanying drawing 3) proves that high molecular weight chitosan radiation degradation post crystallization degree reduces, and this has well water-soluble consistent with the lower molecular weight or the water-soluble chitosan of the preparation of radiation degradation method.Radiation degradation front and rear casing glycan sample is done ultimate analysis (seeing embodiment), and the N constituent content changes very little, and the visible radiation degraded can not produce significantly the chitosan active amine and destroy.In the aftertreatment of degraded product, use aqueous hydrogen peroxide solution as discoloring agent, eliminated the influence that radiation causes to color sample, can obtain outward appearance is color prime white or flaxen product.In addition, can be by selecting the molecular weight (accompanying drawing 5,6) of different radiation dose and radiation condition control radiation degradation product.Be not difficult to find out that it is little that radiation method possesses environmental pollution, easy to operate, fast, the productive rate height, characteristics such as cost is low, and experimental repeatability is good, and molecular weight is easy to control both can be used for the preparation of small amount of sample, have again industrialized may.
Description of drawings
Fig. 1: chitosan radiation degradation schema.
Fig. 2: infrared spectrogram before and after the chitosan radiation degradation: (a) sample before the degraded of chitosan solid; (b) chitosan solid Co
60Gamma-radiation 250kGy irradiation-induced degradation product; (c) chitosan 1.5 (w) %HAc/5 (w) %H
2O
2Solution
60Co gamma-radiation 40kGy irradiation-induced degradation product; (d) chitosan 5 (w) %H
2O2 solution
60Co gamma-radiation 25kGy irradiation-induced degradation product.
Fig. 3: the WAXD curve before and after the chitosan irradiation-induced degradation: (a) sample before the degraded of chitosan solid; (b) chitosan solid
60Co gamma-radiation 200kGy irradiation-induced degradation product; (c) chitosan 5 (w) %H
2O2 solution
60Co gamma-radiation 25kGy irradiation-induced degradation product; (d) chitosan 1.5 (w) %HAc/5 (w) %H
2O
2Solution
60Co gamma-radiation 40kGy irradiation-induced degradation product.
Fig. 4: chitosan molecule amount equation and viscosity-average molecular weight condition determination.
Fig. 5: viscosity-average molecular weight～radiation dose figure before and after the chitosan solid radiation degradation.
Fig. 6: 5.0 (w) % hydrogen peroxide/1.5 (w) % acetate/5.0% chitosan solution relative viscosity is with the variation of radiation dose.
Embodiment
Further specify the present invention below by embodiment, but the present invention is not limited to this.
In following examples, the chitosan molecule amount adopts viscosimetry to be recorded by Ubbelohde viscometer, and condition determination and calculation formula are seen accompanying drawing 4.
Infrared spectrogram is recorded by Bio-Rad FTS135 infrared spectrometer by the KBr compressing tablet.
The X-ray diffraction spectrogram is recorded by D/max2500V PC X-ray diffractometer of science with the chitosan powder.
Ultimate analysis is recorded by Vario EL elemental analyser.
Embodiment 1:
With purified high molecular weight chitosan (molecular weight M
η=5.8 * 10
5Gmol
-1, deacetylation DA 〉=90%, nitrogen content N%=7.47, Zhejiang Yuhuan marine organisms company limited provides) and solid packs in the polyethylene plastic bag, direct sealing or vacuumize the back inflated with nitrogen and seal,
60Co gamma-radiation irradiation-induced degradation, dosage 200kGy, dose rate 9.0kGyh
-1Solid behind the irradiation is with acetate or dissolve with hydrochloric acid solution, the aftertreatment son amount chitosan that makes low score, molecular weight M
η=5.6 * 10
4Gmol
-1, productive rate 90.0%, N%=6.10.Infrared spectra behind the pre-irradiation and WAXD curve are seen accompanying drawing 2 and 3.
Embodiment 2:
High molecular weight chitosan (with embodiment 1) is made 5% (w) acetic acid solution, and acetic acid concentration is 1.5% (w).Gamma-radiation irradiation-induced degradation under the room temperature, dosage 100kGy, dose rate 7.0kGyh
-1Aftertreatment gets water-soluble low molecular weight chitosan, molecular weight M
η=1.7 * 10
4Gmol
-1, productive rate 60%, N%=6.90.Infrared spectra behind the pre-irradiation and WAXD curve are seen accompanying drawing 2 and 3.
Embodiment 3:
High molecular weight chitosan (with embodiment 1) is made 5% (w) acetic acid solution, and acetic acid concentration is 1.5% (w), and adding hydrogen peroxide to its content is 5.0% (w), gamma-radiation irradiation-induced degradation under the room temperature, dosage 25kGy, dose rate 0.35kGyh
-1Aftertreatment gets water-soluble low molecular weight chitosan, molecular weight M
η=1.2 * 10
4Gmol
-1, productive rate 60%, N%=6.00.Infrared spectra behind the pre-irradiation and WAXD curve are seen accompanying drawing 2 and 3.
Embodiment 4:
High molecular weight chitosan (with embodiment 1) is packed in the thin mouthful of peace bottle, and adding hydrogen peroxide to its content is 5.0% (w), and chitosan concentration is 5% (w), gamma-radiation irradiation-induced degradation under the room temperature, dosage 100kGy, dose rate 7.0kGyh
-1Aftertreatment gets water-soluble low molecular weight chitosan, molecular weight M
η=1.2 * 10
4Gmol
-1, productive rate 60%, N%=5.00.Infrared spectra behind the pre-irradiation and WAXD curve are seen accompanying drawing 2 and 3.
Embodiment 5:
With purified high molecular weight chitosan (M
η=4.8 * 10
5Gmol
-1, DA ≈ 75%, N%=6.96, Huaian, Anhui bio tech ltd provides) and solid packs in the polyethylene plastic bag, direct sealing or vacuumize the back inflated with nitrogen and seal,
60Co gamma-radiation irradiation-induced degradation, dosage 250kGy, dose rate 9.0kGyh
-1Solid behind the irradiation is with acetate or dissolve with hydrochloric acid solution, the aftertreatment son amount chitosan that makes low score, molecular weight M
η=5.0 * 10
4Gmol
-1, productive rate 90%, N%=6.63.
Claims (5)
1. solid state radiation method for preparing water-soluble chitosan mainly contains two steps of irradiation-induced degradation and aftertreatment:
A) use
60The Co gamma-radiation carries out the room temperature irradiation-induced degradation to refined chitosan polity, and irradiation dose is 50～300kGy;
B) product that step a is obtained is dissolved in mineral acid or the aqueous solutions of organic acids, and the mass concentration of chitosan is 1～15%, and mineral acid or organic acid mass concentration are 0.5～15%; Regulate pH to 6～8 with 0.2～0.6M alkaline solution, filter; Add 30 (w) % superoxol in the filtrate, stir, treat the filtrate color take off light after, concentrating under reduced pressure filtrate is to 10～50% of original volume; Add methyl alcohol, ethanol or acetone, or the mixed solution of ethanol and acetone, the ethanol/acetone volume ratio: 1/9～9/1, to leave standstill, filtration is desolvated, and with ethanol or washed with isopropyl alcohol 1～3 time, uses washing with acetone then, and vacuum-drying promptly gets water-soluble low molecular weight chitosan.
2. solution method of radiating for preparing water-soluble chitosan mainly contains sample dissolution, irradiation-induced degradation and three steps of aftertreatment:
A) will be dissolved in mineral acid or the aqueous solutions of organic acids through the purified chitosan, or be dissolved in the aqueous hydrogen peroxide solution, or be dissolved in and be added with in mineral acid or the organic acid aqueous hydrogen peroxide solution, wherein the mass concentration of chitosan in the aqueous solution is 1～15%, mineral acid or organic acid mass concentration are 0.5～15.0%, and the mass concentration of hydrogen peroxide is 1～30%;
B) solution that step a is obtained is used
60The Co gamma-radiation carries out room temperature irradiation degraded, and irradiation dose is 1～200kGy;
C) in the poly-chitose solution of step b radiation degradation, add 0.2～0.6M alkaline solution, regulate pH to 6～8, filter; Add 30 (w) % superoxol in the filtrate, stir, treat the filtrate color take off light after, concentrating under reduced pressure filtrate is to 10～50% of original volume; Add methyl alcohol, ethanol or acetone, or the mixed solution of ethanol and acetone, the volume ratio of ethanol and acetone is 1: 9～9: 1, leave standstill, filtration is desolvated, with ethanol or washed with isopropyl alcohol 1～3 time, use washing with acetone then, vacuum-drying promptly gets water-soluble low molecular weight chitosan.
3. method as claimed in claim 1 or 2 is characterized in that, described chitosan viscosity-average molecular weight is greater than 15 * 10
4Gmol
-1, deacetylation is greater than 70%.
4. method as claimed in claim 1 or 2 is characterized in that, described mineral acid or organic acid are one or two or more kinds mixing acid in hydrochloric acid, formic acid, acetate, citric acid and the lactic acid.
5. method as claimed in claim 1 or 2 is characterized in that, described alkaline solution is NaHCO
3The aqueous solution or KOH, NaOH and NaHCO
3Mixing solutions.
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100369937C (en) * | 2006-09-29 | 2008-02-20 | 北京大学 | Preparing low molecular weight chitosan by sensitizing radiation degradation method |
| CN100376590C (en) * | 2005-08-17 | 2008-03-26 | 武汉拓扑科技发展有限公司 | Konjak oligosaccharide preparation method |
| CN100556912C (en) * | 2007-01-05 | 2009-11-04 | 湖北省农业科学院农产品加工与核农技术研究所 | Irradiation-induced degradation swelling konjaku powder prepares in Portugal's sweet dew, the method for oligomeric liquid glucose |
| CN101891507A (en) * | 2010-07-15 | 2010-11-24 | 黑龙江省科学院技术物理研究所 | Method for degrading weathered coal with gamma ray |
| CN101508790B (en) * | 2009-02-24 | 2011-05-11 | 华南理工大学 | Method for preparing low-molecular weight chitosan by using impulse electric field |
| CN102585023A (en) * | 2012-01-03 | 2012-07-18 | 浙江大学 | Ionizing radiation degradation method for sea cucumber polysaccharide |
| CN103168778A (en) * | 2013-03-22 | 2013-06-26 | 浙江大学 | Pepper antioxidant enzyme accelerant and preparation and usage method thereof |
| CN107652373A (en) * | 2017-09-26 | 2018-02-02 | 广州华大生物科技有限公司 | A kind of preparation method of low-molecular weight chitoglycan |
| CN110041447A (en) * | 2019-05-14 | 2019-07-23 | 深圳市仙迪化妆品有限公司 | Small molecule algae chitosan and the preparation method and application thereof |
| CN110075002A (en) * | 2019-05-14 | 2019-08-02 | 深圳市仙迪化妆品有限公司 | A kind of preparation method of the algae chitosan stoste without preservative |
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Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100376590C (en) * | 2005-08-17 | 2008-03-26 | 武汉拓扑科技发展有限公司 | Konjak oligosaccharide preparation method |
| CN100369937C (en) * | 2006-09-29 | 2008-02-20 | 北京大学 | Preparing low molecular weight chitosan by sensitizing radiation degradation method |
| CN100556912C (en) * | 2007-01-05 | 2009-11-04 | 湖北省农业科学院农产品加工与核农技术研究所 | Irradiation-induced degradation swelling konjaku powder prepares in Portugal's sweet dew, the method for oligomeric liquid glucose |
| CN101508790B (en) * | 2009-02-24 | 2011-05-11 | 华南理工大学 | Method for preparing low-molecular weight chitosan by using impulse electric field |
| CN101891507A (en) * | 2010-07-15 | 2010-11-24 | 黑龙江省科学院技术物理研究所 | Method for degrading weathered coal with gamma ray |
| CN101891507B (en) * | 2010-07-15 | 2013-11-13 | 黑龙江省科学院技术物理研究所 | Method for degrading weathered coal with gamma ray |
| CN102585023B (en) * | 2012-01-03 | 2015-04-29 | 浙江大学 | Ionizing radiation degradation method for sea cucumber polysaccharide |
| CN102585023A (en) * | 2012-01-03 | 2012-07-18 | 浙江大学 | Ionizing radiation degradation method for sea cucumber polysaccharide |
| CN103168778A (en) * | 2013-03-22 | 2013-06-26 | 浙江大学 | Pepper antioxidant enzyme accelerant and preparation and usage method thereof |
| CN107652373A (en) * | 2017-09-26 | 2018-02-02 | 广州华大生物科技有限公司 | A kind of preparation method of low-molecular weight chitoglycan |
| CN107652373B (en) * | 2017-09-26 | 2018-11-27 | 广州华大生物科技有限公司 | A kind of preparation method of low-molecular weight chitoglycan |
| CN110041447A (en) * | 2019-05-14 | 2019-07-23 | 深圳市仙迪化妆品有限公司 | Small molecule algae chitosan and the preparation method and application thereof |
| CN110075002A (en) * | 2019-05-14 | 2019-08-02 | 深圳市仙迪化妆品有限公司 | A kind of preparation method of the algae chitosan stoste without preservative |
| CN110407955A (en) * | 2019-08-12 | 2019-11-05 | 浙江海洋大学 | A kind of preparation method of water soluble marine oligomeric polysaccharide |
| CN110407955B (en) * | 2019-08-12 | 2021-09-14 | 浙江海洋大学 | Preparation method of water-soluble marine oligosaccharide |
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