JP4140741B2 - Method for producing dry chitin powder or dry chitosan powder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Chitin is an extremely important substance that is used as a raw material for the production of chitosan and for the production of glucosamine, which is expected as an agent for treating arthritis. Chitosan is used as a flocculant for water purification, and in recent years, it is expected to have an effect of dietary fiber due to indigestibility, and by having many amino groups, it absorbs bile acids in the digestive tract, and serum cholesterol Since it shows a lowering action, chitosan is expected to be applied to functional foods utilizing the cholesterol action. Development into biodegradable polymers, dietary supplements, and the like is underway. The present invention relates to a method for producing dry chitin powder or dry chitosan powder.
[0002]
[Prior art]
Conventionally, powder chitin or powder chitosan is, for example, deproteinized and decalcified from shells of crabs, shrimp or shrimp, etc. or squid cartilage, deacetylated as necessary, washed with water, dried and then coarsely crushed. Further, it was pulverized by a pulverizer to obtain powdered chitin and powdered chitosan.
[0003]
[Problems to be solved by the invention]
However, a drier is required to convert hydrous chitin or hydrous chitosan into dry chitin or dry chitosan having a water content of 10% or less, and a considerable drying time is required. Furthermore, physical property deterioration due to pulverization of the dried product is severe, and reduction of physical property deterioration has been demanded.
[0004]
Thus, in order to obtain dry chitin powder or dry chitosan powder, enormous production equipment and a great deal of production time are required, and a cheap and efficient production method for dry chitin powder or dry chitosan powder is desired. It was.
[0005]
[Means for Solving the Problems]
Therefore, as a result of various investigations, the present inventors have dried the water content to 10% or less by directly putting the water-containing chitin or chitosan into the pulverizer without crushing the difficult-to-grind chitin or chitosan. It has been found that chitin powder or chitosan powder can be obtained. Furthermore, it has been found that deterioration in physical properties due to pulverization is reduced by pulverization in a water-containing state. As a result, since the drying equipment is not required and there is no step of performing only drying, the manufacturing method is inexpensive and highly efficient. The present invention has been completed based on the above findings.
[0006]
That is, the present invention
(1) By pulverizing hydrous chitin or hydrous chitosan having a water content of 20 to 80% before pulverization and an average particle diameter of 300 μm to 1 cm with a pulverizer, pulverizing with a pulverizer and simultaneously drying. A method for producing a dried chitin powder or a dried chitosan powder, characterized in that the dried chitin powder or dried chitosan powder having an average particle size of 30 to 200 μm is obtained;
(2) The method according to (1), wherein the pulverizer for pulverizing hydrous chitin or hydrous chitosan is an air-jet jet mill,
(3) The method according to (1) or (2), wherein the moisture content of the dried chitin powder or the dried chitosan powder after pulverization is 10% or less,
About.
[0007]
In the present invention, chitin is usually obtained from, for example, crustacean crusts such as crabs and shrimps, deproteinized with dilute alkali or enzyme, further decalcified with dilute acid to remove ash, and the reaction is completed. Thereafter, it is obtained by washing with water several times, but is not particularly limited to this method. The hydrated chitin may be, for example, a hydrated product obtained by washing with water by the method described above, or may be a hydrated product obtained by adding water to a dried product. Chitosan can be obtained, for example, by deacetylating chitin in a strong alkali agent such as sodium hydroxide or potassium hydroxide and then washing with water several times, but is not particularly limited to this method. The hydrated chitosan may be, for example, a hydrated product obtained by washing with water by the method described above, or may be a product obtained by adding water to a dried product.
[0008]
The pulverizer of the present invention is not particularly limited, and for example, it is preferable to perform hydrous pulverization using a pulverizer that involves the use of a large amount of air, and an airflow jet mill is particularly preferable. The water content of the water-containing chitin or water-containing chitosan before pulverization is usually preferably in the range of 20 to 80%, particularly preferably 50 to 70% of water-containing chitin or water-containing chitosan obtained by washing with water during production. The average particle size of hydrous chitin or hydrous chitosan before pulverization is preferably 300 μm or more and 1 cm or less, and particularly preferably about 1 to 5 mm. The moisture content of the dried chitin powder or dried chitosan powder after pulverization is preferably 10% or less, particularly preferably 0.5 to 5%. The average particle size of the dried chitin powder or dried chitosan powder after pulverization is preferably 300 μm or less, more preferably 30 to 200 μm, and particularly preferably 50 to 120 μm. The deterioration of physical properties due to pulverization is usually about 15 to 35% of the viscosity retention before and after airflow jet mill pulverization with a dry product, but the water content (for example, the water content of hydrated chitin or hydrated chitosan is 20 to 80%). ), The viscosity retention before and after the airflow jet mill pulverization is improved to 25 to 45%, and the deterioration of physical properties is reduced.
[0009]
【The invention's effect】
The present invention is a very effective production method for obtaining high-quality dry chitin powder or dry chitosan powder without pulverizing hydrous chitin or hydrous chitosan with a pulverizer and providing a separate drying step.
[0010]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
Example 1
The dried product has a viscosity of 780 mPa · s, a deacetylation degree of 97%, an average particle size of 2.5 mm, and a moisture content of 4.3%, 22.2%, 44.5%, 56.0%, and 77.0%. The dry chitosan powder was obtained by pulverizing with an air-flow jet mill (Rikishin Machine Seisakusho, KV-15 type). Table 1 shows the viscosity, average particle diameter, water content, and degree of deacetylation of the dried chitosan powder.
[0011]
[Table 1]
Water content before grinding Viscosity Average particle size Water content Deacetylation degree
(%) (MPa · s) (μm) (%) (%)
4.3 230 180 6.2 96.0
22.2 260 180 6.9 97.0
44.5 280 180 6.8 97.0
56.0 270 170 7.6 97.0
77.0 250 170 7.9 96.0
[0012]
Example 2
The dried product has a viscosity of 780 mPa · s, a deacetylation degree of 97%, an average particle size of 2.5 mm, and a moisture content of 4.3%, 22.2%, 44.5%, 56.0%, and 77.0%. The dry chitosan powder was obtained by pulverizing with an airflow jet mill (Hosokawa Micron Co., Ltd., ACM-10 type). Table 2 shows the viscosity, average particle diameter, water content, and degree of deacetylation of the dried chitosan powder.
[0013]
[Table 2]
Water content before grinding Viscosity Average particle size Water content Deacetylation degree
(%) (MPa · s) (μm) (%) (%)
4.3 180 160 5.5 97.0
22.2 225 150 5.9 97.0
44.5 208 150 5.4 97.0
56.0 211 140 6.8 97.0
77.0 204 140 7.8 97.0
[0014]
Example 3
Grinded with an air-jet jet mill (Hosokawa Micron Corporation, Ultraplex) using two chitins with a dried product viscosity of 1200 mPa · s, an average particle size of 3.5 mm, and a moisture content of 5.0% and 50.0%. As a result, dry chitin powder was obtained. Table 3 shows the viscosity, average particle diameter, and water content of the dried chitin powder.
[0015]
[Table 3]
Water content before grinding Viscosity Average particle size Water content
(%) (MPa · s) (μm) (%)
5.0 380 140 5.8
50.0 430 130 6.0
[0016]
The measured value of the viscosity is the viscosity of chitosan obtained by adding 200 ml of 48% caustic soda to 10 g of chitin and reacting at 95 ° C. for 3 hours.
[0017]
Example 4
Using two chitosans having a dried product viscosity of 310 mPa · s, a degree of deacetylation of 92%, an average particle size of 3.2 mm, a moisture content of 6% and 60%, an air-jet jet mill (Hosokawa Micron Co., Ltd., ACM- 10 type) and sieved through a 180 μm net to obtain dry chitosan powder. Table 4 shows the viscosity, average particle diameter, water content, and degree of deacetylation of the dried chitosan powder.
[0018]
[Table 4]
Water content before grinding Viscosity Average particle size Water content Deacetylation degree
(%) (MPa · s) (μm) (%) (%)
6.0 120 140 3.5 92.0
60.0 140 120 3.4 92.0

Claims (3)

The average particle size is obtained by pulverizing hydrous chitin or hydrous chitosan having a water content of 20 to 80% before pulverization and an average particle size of 300 μm to 1 cm with a pulverizer, and simultaneously pulverizing with a pulverizer and drying. A method for producing a dry chitin powder or a dry chitosan powder, characterized in that a dry chitin powder or a dry chitosan powder of 30 to 200 μm is obtained.  The method according to claim 1, wherein the pulverizer for pulverizing the hydrous chitin or the hydrous chitosan is an airflow type jet mill. The method according to claim 1 or 2, wherein the dried chitin powder or the dried chitosan powder after pulverization has a water content of 10% or less.