JP2006233113A - Fine particle chitosan and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fine particle chitosan produced by crushing polymer chitosan into fine particles, and to provide a method for producing the fine particle chitosan, by which the fine particle chitosan can efficiently be obtained. <P>SOLUTION: The fine particle chitosan is characterized by having an average particle diameter of ≤20 μm and an average mol. wt. of ≥250,000 and not forming a W/O emulsion. The method for producing the fine particle chitosan comprises dispersing chitosan in a solvent to prepare a chitosan dispersion, wet-crushing the chitosan dispersion with a medium stirring mill. It is preferable to add a hydrophilic emulsifier having an HLB of ≥11 as a dispersant to the chitosan dispersion. It is preferable to add the dispersant in an amount of 0.1 to 5 mass% based on the chitosan dispersion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to fine particle chitosan and a method for producing the same, and more specifically, by finely pulverizing chitosan having a relatively large average molecular weight and not forming a W / O emulsion, and wet pulverization using a medium stirring mill. The present invention relates to a method for producing fine particle chitosan.

  Chitosan is obtained by deacetylating chitin contained in crustaceans such as shrimp and crabs, insects such as beetles and crickets, squid cartilage, mushrooms and fungal cell walls. -Glucosamine is a polysaccharide having a molecular weight of 10,000 to 1,000,000 with β1-4 binding.

  Chitosan has been tried to be used in various fields such as chemicals, pharmaceuticals, medical products, cosmetics, foods, and other household products using its physical properties, chemical properties, and functionality. In Japan, development of so-called functional foods utilizing physiological functions such as cholesterol-lowering action, lipid absorption inhibitory action, blood pressure effect action and the like of chitosan has been carried out.

  However, chitosan is insoluble in water, and when chitosan is pulverized by dry pulverization using a jet mill, mill, or other pulverizer, the resulting chitosan particles have a particle size of approximately 50 μm or more. When added, there was a problem that the rough feeling of chitosan particles remained on the tongue, and turbidity and precipitation derived from chitosan were liable to occur.

  Therefore, as a method for obtaining smaller chitosan particles, for example, Patent Document 1 below is characterized in that chitosan is heated and dissolved in dilute sulfuric acid, and the obtained dilute sulfuric acid aqueous solution of chitosan is cooled to precipitate chitosan. A method for producing chitosan microparticles is disclosed.

  Patent Document 2 below discloses a method for producing chitosan fine particles, wherein chitosan is precipitated by adding sulfuric acid and / or sulfate to an aqueous solution of chitosan organic acid or inorganic acid other than sulfuric acid. .

  Patent Document 3 listed below discloses chitosan microparticles having an average particle size of 10 μm or less, and describes that chitosan is dissolved in an acid aqueous solution and the chitosan aqueous solution is spray-dried. ing.

  In Patent Document 4 below, a solution obtained by dissolving chitosan in an acidic aqueous solution is coagulated and regenerated in a basic solution, and the resulting coagulated product is washed and pulverized and dispersed, and the dispersion is placed in a high-temperature atmosphere. Disclosed is a method for producing ultrafine spherical chitosan which is characterized by being discharged and dried together with pressurized air.

  Patent Document 5 listed below discloses a method for producing chitosan granules characterized in that an acid aqueous solution of chitosan is spray-dried in an ammonia atmosphere.

  Patent Document 6 below discloses a method for producing non-spherical shaped chitosan fine particles characterized by injecting a W / O emulsion of an aqueous chitosan acid solution into a mixed solution of an amine and an alcohol to coagulate and precipitate the chitosan fine particles. Yes.

  Patent Document 7 below discloses a method for producing spherical chitosan fine particles characterized by injecting a W / O emulsion of an aqueous chitosan acid solution into an organic solvent alone or an organic solvent containing a base to coagulate and precipitate the spherical chitosan fine particles. Has been.

  On the other hand, in order to improve the dispersibility of poorly soluble salts such as calcium phosphate and magnesium carbonate and cellulose, a method of wet pulverizing them is known. For example, Patent Document 8 below discloses phosphoric acid having specific physical properties. In a water slurry prepared by adding water to calcium to prepare an aqueous suspension of calcium phosphate of a predetermined concentration, and wet-pulverizing the aqueous suspension to meet specific requirements using a wet pulverizer A method for producing a calcium phosphate dispersion is disclosed in which 5 to 100 parts by weight of a hydrophilic emulsifier having an HLB of 10 or more is added to 100 parts by weight of calcium phosphate.

  Patent Document 9 listed below discloses a method for producing a magnesium carbonate dispersion, which includes a step of wet-grinding a magnesium carbonate suspension in which a dispersant is dissolved.

Patent Document 10 below contains 2% by weight or more of a micronized cellulose material having a cumulative volume of 50% and a particle size of 0.3 to 6 μm and a cumulative volume ratio of particles of 3 μm or less of 25% or more. A food material comprising an aqueous suspension of a micronized cellulose material characterized by the above is disclosed, and the food material is obtained by subjecting a cellulose material to a depolymerization treatment and performing wet pulverization with a medium stirring wet pulverizer. It is described.
JP-A-7-330807 JP-A-9-143203 JP 63-20301 A Japanese Patent Publication No. 4-55610 Japanese Patent Publication No. 6-23201 JP-A-7-188303 JP 7-118305 A JP-A-6-127909 JP 11-21123 A JP-A-4-218357

  However, all the methods disclosed in Patent Documents 1 to 7 have various problems because micronization is performed after chitosan is used as an acid solution.

  For example, in the methods disclosed in Patent Documents 1 and 2, chitosan is dissolved by heating in an acid solution. Therefore, there is a high possibility that the molecular weight of chitosan is reduced during the process.

  In addition, in the methods disclosed in Patent Documents 3 to 5, since heating is not performed when chitosan is dissolved in an acid solution, the chitosan solution has a high viscosity and is likely to cause a problem in handling. There was a problem that the molecular weight and the concentration during dissolution were greatly limited. Furthermore, in the methods disclosed in Patent Documents 3 and 5, since chitosan is spray-dried in the form of an acid solution, there is a possibility that the molecular weight is reduced during drying.

  Chitosan is very widely defined as its molecular weight range, but there are significant differences in physical properties, chemical properties, and functionality due to differences in molecular weight, and low molecular weight chitosan obtained by the above method is a high molecular chitosan. Of these properties could not be obtained.

  On the other hand, in the methods disclosed in Patent Documents 6 and 7, since the obtained chitosan forms a W / O emulsion, its properties are completely different from those of ordinary chitosan.

  The methods disclosed in Patent Documents 8 to 10 are applied to calcium phosphate, magnesium carbonate, and cellulose having different physical properties from chitosan, and when applied to chitosan that is a charged polymer, the method is efficient. I didn't know if it could be made fine.

  Accordingly, it is an object of the present invention to provide a fine particle chitosan obtained by finely polymerizing chitosan and a method for producing fine particle chitosan capable of efficiently obtaining the fine particle chitosan.

  In order to achieve the above object, one of the present invention provides a fine particle chitosan having an average particle diameter of 20 μm or less, an average molecular weight of 250,000 or more, and not forming a W / O emulsion. Is.

  The fine particle chitosan of the present invention is obtained by making polymer chitosan into fine particles as it is compared with conventional fine particle chitosan, and does not form a W / O emulsion, so it retains the properties unique to polymer chitosan. . Moreover, since the particle diameter is very small, even if it mix | blends with food-drinks etc., a rough feeling and precipitation are not produced.

  Another aspect of the present invention provides a method for producing fine particle chitosan characterized in that chitosan is dispersed in a solvent to prepare a chitosan dispersion, and the chitosan dispersion is wet-ground using a medium stirring mill. To do.

  According to the production method of the present invention, polymeric chitosan can be efficiently made into fine particles, and fine particle chitosan that can be easily used for foods and drinks can be obtained.

  In the method for producing fine particle chitosan of the present invention, it is preferable to add a hydrophilic emulsifier having an HLB of 11 or more as a dispersant to the chitosan dispersion, and the dispersant is added to the chitosan dispersion by 0.1%. It is preferable to add ~ 5 mass%. Moreover, it is preferable to use a sucrose fatty acid ester as the dispersant.

  According to these, the dispersibility of the chitosan fine particles can be stabilized during wet pulverization, so that finer fine particle chitosan can be obtained.

  Moreover, it is preferable to prepare so that the density | concentration of the said chitosan dispersion may be 1-10 mass%, and it is preferable to use a thing with an average particle diameter of 50-200 micrometers as said chitosan. According to these, chitosan can be pulverized efficiently.

  Furthermore, it is preferable to use chitosan having an average molecular weight of 250,000 or more and a deacetylation degree of 70% or more as the chitosan. According to this, the polymer chitosan can be made into fine particles more efficiently.

  ADVANTAGE OF THE INVENTION According to this invention, the fine particle chitosan which retains the property of polymeric chitosan and can be easily utilized for food-drinks etc. and its manufacturing method can be provided. The fine particle chitosan of the present invention has an unprecedented fine particle size, and does not cause roughness or precipitation even when blended with food or drink.

  First, the manufacturing method of the microparticulate chitosan of this invention is demonstrated.

  The chitosan used in the present invention is not particularly limited in its origin, and for example, those obtained by deacetylating chitin obtained from crustaceans such as crabs and shrimps can be used.

  The molecular weight and deacetylation degree of chitosan are not particularly limited, but in the present invention, chitosan having an average molecular weight of 250,000 or more and a deacetylation degree of 70% or more is preferably used. Such chitosans having various molecular weights and deacetylation degrees are commercially available. For example, the trade name “chitosan PSH-80” (manufactured by Yaizu Suisan Chemical Co., Ltd.), the trade name “Daichitosan 100D” (large) Nissei Kasei Kogyo Co., Ltd.), trade name "Daichitosan M" (Daiichi Seika Kogyo Co., Ltd.), trade name "Kimikachitosan S" (Kimika Co., Ltd.), etc. Can be used.

  First, raw material chitosan is dispersed in a solvent to prepare a chitosan dispersion. Water is preferably used as a solvent for dispersing chitosan. The concentration of the chitosan dispersion is preferably 1 to 10% by mass, and more preferably 1 to 5% by mass. If the chitosan concentration is too high, the viscosity of the chitosan dispersion becomes high and it becomes difficult to efficiently make fine particles, and if the chitosan concentration is too low, the treatment capacity decreases, which is not preferable. In addition, in this invention, it is preferable to use the raw material chitosan previously grind | pulverized by the well-known method until the average particle diameter will be 50-200 micrometers. Thereby, it can pulverize efficiently.

  Further, in wet pulverization, as the particle size of the target product decreases, the particles agglomerate and hinder the formation of fine particles. In particular, charged chitosan tends to aggregate, so in the present invention, an emulsifier is used as a dispersant. It is preferable to add. Examples of emulsifiers that can be used in foods include monoglycerin fatty acid esters, organic acid monoglycerides, polyglycerin fatty acid esters, propylene glycol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, and lecithin. In the present invention, it is preferable to use a hydrophilic emulsifier having an HLB of 11 or more as a dispersant. Among them, polyglycerin fatty acid ester and sucrose fatty acid ester are preferably used. From the viewpoint of flavor and handling, sucrose fatty acid ester is preferable. It is particularly preferable to use By using a hydrophilic emulsifier having an HLB of 11 or more, the dispersibility of chitosan fine particles can be stabilized during wet pulverization, and finer fine particles can be formed. Since no O emulsion is formed, it is possible to obtain fine particle chitosan having the properties of chitosan. In this invention, it is preferable to add the said dispersing agent 0.1-5 mass% with respect to the said chitosan dispersion liquid, and it is more preferable to add 0.1-1 mass%. More specifically, the amount of the dispersant added is preferably 0.1 to 60% by mass and more preferably 10 to 50% by mass with respect to chitosan.

  Next, the chitosan dispersion is wet pulverized using a medium stirring mill such as a ball mill or a bead mill. The bead mill is an apparatus that pulverizes the target product into fine particles by stirring at high speed together with the target product dispersed in a solvent and the beads serving as the grinding media. In the present invention, in order to obtain chitosan having a smaller particle size. It is preferable to use a bead mill having a smaller media diameter. Specifically, the size of the beads is preferably 1 mmφ or less. In addition, since the pulverization efficiency is reduced by using smaller beads, first, micronization is performed using relatively large beads of 1 to several mmφ, and then by micronization using small beads, Efficient atomization can be performed. Other pulverization conditions may be appropriately determined according to the apparatus used so that the average particle size of the obtained fine particle chitosan is 20 μm or less, more preferably 10 μm or less.

  Fine chitosan and beads are fractionated from the chitosan dispersion subjected to wet pulverization as described above. The method for separating fine particle chitosan and beads is not particularly limited, and for example, sieving can be performed using a mesh or the like.

  Then, the finely divided finely divided chitosan is appropriately washed with water and then dried. As a drying method, a known method such as hot air drying, air blowing drying, fluidized bed drying, spray drying, vacuum drying, freeze drying and the like can be adopted. In the present invention, vacuum drying or freeze drying is preferably employed. In the case of these methods, the fine chitosan can be efficiently dried without being scattered during the drying.

  The fine particle chitosan obtained as described above preferably has an average particle size of 20 μm or less, an average molecular weight of 250,000 or more, and does not form a W / O emulsion.

  The particle size of the fine particle chitosan can be measured, for example, by a method such as a microscope method, a light scattering method, a sieving method, a liquid phase precipitation method, an inertial collision method, or an electric resistance method. Moreover, an average molecular weight can be measured by methods, such as a vapor pressure osmosis method, a light-scattering method, an electrophoresis method, and GPC-HPLC method, for example.

  The product name “chitosan PSH-80” (average molecular weight of 500,000 or more, degree of deacetylation 80%, average particle size 120 μm, manufactured by Yaizu Suisan Chemical Co., Ltd.) is dispersed in water so as to be 2% by mass. The product name “DK ester F-160” (sucrose fatty acid ester, HLB = 15, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an agent is added and mixed so as to be 0.4% by mass (20% by mass with respect to chitosan). A chitosan dispersion was prepared. This dispersion was wet pulverized under the following conditions.

Wet pulverization conditions and pulverizer: Trade name “Continuous Ready Mill SLG-03” (Bead Mill, manufactured by AIMEX)
・ Media: 2mmφ zirconia beads ・ Media filling rate: 85%
-Stirring speed: 2,000 rpm
・ Liquid feeding amount: 30 ml / min
-Number of times of liquid passing: 20 times

  And the dispersion liquid of the fine particle chitosan with an average particle diameter of 37 micrometers was obtained, and it sieved with the media using the sieve of 32 mesh (opening 500 micrometers). The average particle size was measured using a particle size distribution meter “LA-910” (trade name, Horiba, Ltd.). Further, when the average molecular weight was measured by the HPLC method under the following conditions, no change was observed in the molecular weight before and after the microparticulation.

HPLC conditions / column: TSK-gel guardcolumn PW _XL (trade name, manufactured by Tosoh Corporation)
TSK-gel G4000 PW _XL (trade name, manufactured by Tosoh Corporation)
TSK-gel G3000 PW _XL (trade name, manufactured by Tosoh Corporation)
Eluent: 0.1M NaCl / 0.1N acetic acid = 1/1
Pump flow rate: 0.8 ml / min (trade name “L-7100 type pump”, manufactured by Hitachi, Ltd.)
Column temperature: Room temperature Detector: RI (trade name “L-7490 type RI detector”, manufactured by Hitachi, Ltd.)

  The fine particle chitosan dispersion obtained in Example 1 was further wet pulverized under the following conditions.

Wet pulverization conditions and pulverizer: Trade name “Continuous Ready Mill SLG-03” (Bead Mill, manufactured by AIMEX)
・ Media: 0.5mmφ zirconia beads ・ Media filling rate: 85%
-Stirring speed: 2,500 rpm
・ Liquid feeding amount: 30 ml / min
-Number of times of liquid passing: 10 times

  A dispersion of fine particle chitosan having an average particle size of 1.0 μm was obtained, sieved with media using a 100 mesh (opening 150 μm) sieve, and then freeze-dried to obtain chitosan fine particle powder. The average particle size was measured using a particle size distribution meter “LA-910” (trade name, Horiba, Ltd.). Further, when the average molecular weight was measured by the HPLC method under the same conditions as in Example 1, no change was seen in the molecular weight before and after micronization.

  The fine particle chitosan of the present invention has a fine particle size that has not been obtained as chitosan particles that retain the properties of high molecular chitosan as it is, so that it can be used for beverages and general processed foods that have been difficult until now. Easy. It can also be used as a functional material in fields other than food such as chemicals, pharmaceuticals, medical products, cosmetics, and other household items.

Claims (8)

  A fine particle chitosan having an average particle diameter of 20 μm or less, an average molecular weight of 250,000 or more, and no W / O emulsion formed.   A method for producing fine-particle chitosan, wherein chitosan is dispersed in a solvent to prepare a chitosan dispersion, and the chitosan dispersion is wet-ground using a medium stirring mill.   The method for producing fine particle chitosan according to claim 2, wherein a hydrophilic emulsifier having an HLB of 11 or more is added as a dispersant to the chitosan dispersion.   The method for producing fine particle chitosan according to claim 3, wherein 0.1 to 5% by mass of the dispersant is added to the chitosan dispersion.   The method for producing fine particle chitosan according to claim 3 or 4, wherein a sucrose fatty acid ester is used as the dispersant.   The method for producing fine particle chitosan according to any one of claims 2 to 5, wherein the chitosan dispersion is prepared so that the concentration thereof is 1 to 10% by mass.   The method for producing fine particle chitosan according to any one of claims 2 to 6, wherein the chitosan having an average particle diameter of 50 to 200 µm is used.   The method for producing fine particle chitosan according to any one of claims 2 to 7, wherein chitosan having an average molecular weight of 250,000 or more and a deacetylation degree of 70% or more is used as the chitosan.