KR100242747B1 - Process for producing low molecular chitosan solution which has less puckery taste and fluent amino acid - Google Patents

Abstract

The present invention relates to a method for producing a chitosan solution, and more specifically, chitosan, which is rich in crustaceans such as crabs and shrimp, is made low in molecular weight while retaining many amino groups inherent in chitosan, so as to be quickly absorbed by the human body, and eliminates astringent taste. When the final product is used, it can be conveniently used for various purposes such as soft drinks, food, food additives, cosmetics, and medicines.

In other words, a specific oxidant is added to the chitosan solution in which chitosan is dissolved in an organic acid, which is then treated in a reaction vessel having a reduced pressure of 450 to 760 mmHg and a reaction temperature of 50 to 100 ° C. to form a chitosan-gel having a gel form like starch syrup. By dissolving it in distilled water again, it produced low-molecular-type chitosan solution with less astringent taste and a large amount of amino group residue, which can be conveniently used in cosmetics and medical fields such as soft drinks, and improved productivity.

Description

Process for preparing low molecular weight chitosan solution with less salty taste and high residual amount of amino groups

The present invention relates to a method for producing a chitosan solution, and more specifically, chitosan, which is rich in crustaceans such as crabs and shrimp, is made low in molecular weight while retaining many amino groups inherent in chitosan, so as to be quickly absorbed by the human body, and eliminates astringent taste. When the final product is used, it can be conveniently used for various purposes such as soft drinks, foods, food additives, cosmetics, and medicines.

Conventional chitosan is a cell wall component of conjugated fungi whose chemical structure is β (1 → 4) binding polymer of 2-amino-2-deoxyglucose.

Generally, however, deacetylation of β (1 → 4) binding polymer (ie chitin) of 2-acetamino-2-deoxy-D-glucose As a result, the ratio (deacetylation degree) of gulucosamine residues in the sugar linkage is 60% or more, and the soluble portion of the dilute acid is taken.

Chitosan is dissolved only in inorganic acids such as dilute hydrochloric acid and dilute nitric acid, and in organic acids such as acetic acid, lactic acid, ascorbic acid, malic acid, tartaric acid, formic acid, and adipic acid, and is insoluble in neutral to basic aqueous solutions and organic solvents. Molecular weight ranges from tens of thousands to millions of polysaccharides and has a structure similar to cellulose, but unlike cellulose, chitosan has a free amine group in each unit structure, so it is dissolved in water by forming an acid and salt under acidic conditions.

The pH of the chitosan solution depends on the acid and the amount used, but when acetic acid is used, if the pH of the solution is lower than 6, the chitosan is in a dissolved state or above, and gels form and precipitate.

The viscosity of chitosan solution varies depending on molecular weight, deacetylation degree, ionic strength, pH, etc., but the viscosity varies widely from 0.5 to 3,500 cps at a concentration of 0.5% (w / v).

Chitosan, which has a high degree of purification, is tasteless and odorless, but organic acid salts have a unique astringent taste and bitter taste, so there is a limit to using them for food or medicine.

Chitosan is currently manufactured according to the process using shells from crustaceans such as crabs and shrimp as raw materials.

In other words, a small amount of calcium carbonate is removed using dilute hydrochloric acid (HCl) solution in shells of shellfish such as crabs and shrimp, and protein is removed using dilute sodium hydroxide (NaOH) solution. This chitin is treated with concentrated sodium hydroxide (NaOH) or enzymatically deacetylated to yield chitosan.

The chitosan made in this way has been used mainly for wastewater coagulants since ancient times.

The effect of chitosan

First: It can be called ovarian fire.

In other words, it was confirmed that chitosan is indigestible, which is not digested by humans but excreted in manure.

Secondly, animal testing shows that cholesterol is improved.

In other words, a rat experiment with chitosan added to a diet high in cholesterol showed a significant suppression of cholesterol in the blood and liver.

Third: It is the cholesterol-lowering effect of chitosan on humans.

In other words, the blood lipids and fecal bile acid excretion before and after chitosan intake were measured in humans.

Fourth: intestinal metabolism improvement.

The obstructive substance produced by the intestinal bacteria is a substance that induces liver cancer, bladder cancer and skin cancer according to animal experiments, but it has been reported that the intestinal metabolism is smoothed by ingesting chitosan.

Fifth: inhibit blood pressure rise.

Intake of chitosan from normal rats and naturally occurring hypertensive rats has been reported to inhibit blood pressure elevation. In human experiments, chitosan adsorbed chlorine ions in saline and excreted in vitro to inhibit blood pressure rise. .

In addition, as well known chitosan has an antimicrobial action and is widely used as a wound treatment, artificial skin, cosmetics, agricultural materials.

When chitosan is used for food or other purposes, the molecular weight and deacetylation degree of chitosan obtained are important variables. In order to control these parameters with reproducibility, it is important to set conditions such as acid or alkali concentration, reaction time, and reaction temperature in the treatment process. To date, the phenomenon of food development and use shows that chitosan is recognized only as a natural additive among food additives by the Food Sanitation Law. However, only products containing 20% or more of chitosan-oligosaccharide are recognized as chitosan processed foods.Therefore, a few products containing chitosan-oligosaccharides imported from abroad are commercially available, and products added as preservatives or dietary fiber are somewhat developed or marketed. There are many limitations when using chitosan as a prototype.

However, chitosan, a natural food additive, is white or pale yellow powder or flaky with its unique astringent taste and peculiar smell, and is difficult due to difficulty in mixing or tableting in the food manufacturing process due to the inherent physical properties of chitosan in powder or flax. The situation is going through.

To find an example of adding chitosan to foods, mainly from patents, a method of preparing chitosan-containing fruit juice by adding 0.3% to 1.0% by weight of chitosan to fruit juice and heating it (Japanese Patent Laid-Open No. 1-304855) and In order to remove the astringent taste of chitosan, fructo-oligosaccharide or shiitake mushroom extract is added to chitosan having a molecular weight in the range of 1,000 to 20,000 to show no bitterness and astringent taste (Publication No. 96-30381) and to chitosan. A method of removing astringent taste by adding persimmon leaf powder or persimmon leaf extract extract (Japanese Patent Laid-Open No. 8-208709) has been proposed.

On the other hand, in order to lower the molecular weight of chitosan, a method of decomposing chitosan by heating in an aqueous solution of acid (Japanese Patent Laid-Open No. 1-128775) and a method of decomposing chitosan by an enzyme (Japanese Patent Publication No. 63-63388) or chitosan as an oxidizing agent A method of decomposing (Japanese Patent Laid-Open No. 56-33401) or dispersing chitosan in a liquid medium to produce low molecular weight chitosan using hypobromic acid, abromic acid, bromic acid, and salts thereof as oxidizing agents (Japanese Patent Laid-Open No. 56-33401). 8-208708) have been proposed.

Therefore, the conventional method as described above has various problems.

This problem is yet to be proposed how to remove the astringent taste and lower the molecular weight while maintaining the amino group inherent in chitosan to be quickly absorbed by the human body.

The low molecular weight of chitosan by acid decomposition is difficult to control the degree of decomposition, and the heating conditions are difficult, such as heating using strong acid solvent, and the low molecular weight by enzyme is low molecular weight rate due to the reaction specificity by enzyme. There is a problem with efficiency.

In addition, the low molecular weight by the oxidizing agent must first adjust the chitosan to pH 6-7, the concentration of the oxidizing agent according to the low differentiation, and all the obtained low molecular weight has a problem of low amino group content.

In order to solve this problem, a chitosan solution in which chitosan is dissolved in an organic acid is prepared, and a specific oxidizing agent is added to the chitosan, which is then treated at high temperature and high pressure to make a chitosan-gel having a gel form such as starch syrup, and then dissolved in distilled water. The purpose of the present invention is to provide a method for producing a low molecular weight chitosan solution in which the yield is high, economical, and the amino acid is alive while reducing the inherent astringent taste and bitter taste of chitosan.

Hereinafter, the present invention will be described in more detail.

In the present invention, chitosan prepared according to a generally known method is dissolved in acetic acid or lactic acid solution.

In the present invention, potassium permanganate (KMnO4) is added to chitosan-lactic acid solution or chitosan-acetic acid solution (hereinafter referred to as "chitosan-lactic acid solution") at a concentration of 0.3 mg / l or less, which is recommended by WHO. Then, the reaction proceeds at a temperature of 50 to 100 ° C.

At this time, the present invention is subjected to a reduced pressure while rotating to promote the reaction after the addition of the oxidant.

The oxidizing agent used in the present invention is potassium permanganate (KMnO 4), and its amount is preferably 0.3 mg / l or less. The reaction temperature is 50 to 100 ° C. and the revolutions per minute of the reactor is 10 to 120 rpm. And it is preferable that the pressure reduction pressure of a reactor reacts in the range of 450-760 mmHg. In this way, the chitosan-gel having a chewy gel form like starch syrup is made, and then dissolved again with water to reduce the astringent and bitter taste of chitosan, while reducing the color of the product. You can make a solution.

Examples of the acid used in the present invention include inorganic acids such as dilute hydrochloric acid, organic acids such as acetic acid, lactic acid, malic acid, ascorbic acid, propionic acid, tartaric acid and citric acid, and the water used is distilled water, drinking spring water, purified water, and the like. On the other hand, oxidizing agents are potassium permanganate and the like.

The viscosity of chitosan obtained by the present invention ranges from 10 cps to 1,500 cps and the yield is more than 85%. In the present invention, by controlling the reaction temperature, reaction time, the amount of oxidizing agent, etc., it is possible to produce chitosan solution in various cps units, and the low molecular weight chitosan solution is not colored and the product having little decrease in amino group content can be obtained. Chitosan solution with many amino group residues can be made, and the chitosan solution obtained by the present invention has the characteristics as described above for the production of fruit drinks, the manufacture of soft drinks, the cleansing and softening of beverages, the production of soft foods such as tofu, confectionery manufacture, and fish cakes. It can be used. Other food uses include food emulsifiers, metabolic accelerators, and potentially low-calorie food materials.

In agriculture, it can be used as plant pest control agent, tumor growth suppression effect, etc. In medicine, it can be used as surgical sponge, hemostatic agent, antacid, digestion accelerator, artificial dialysis membrane. It can be used as a cationic polymer coagulant for wastewater treatment, and especially as an immobilization carrier, functional membrane, fiber and nonwoven fabric of Hyogo and microorganisms.

EXAMPLE

Specific embodiments of the invention described above are described. The inspection necessary to carry out the present invention was in accordance with the Food Additives Code issued by the Korea Food Industry Association, and the other items are in accordance with the Japan Chitosan Processed Food Standard Standard (Notice of June 1, 7) established by the Japan Foundation, Japan Health and Nutrition Food Association. The inspection was carried out accordingly.

In other words, all used chitosan (polymer or low molecular weight) using deacetylation degree of 95% or more and ash content of 0.5% or less extracted from red crab, and the viscosity of chitosan was 1w / v% in 1w / v% acetic acid solution. The viscosity measured by the Brockfield viscometer at 20 degreeC is shown in cps unit.

In order to measure the free amino group, 5 g of the sample solution was collected in a titration container, 50 ml of water and 0.2 ml of toluidine blue solution were added, mixed sufficiently, and titrated with 1 / 400N-polyvinyl sulfate sulfate solution. Obtain

Free amino group (mol / g) = 1/400 × 1/1000 × F × (VB) × 200 / S ₂ ÷ S ₁

Where F is the titer of 1 / 400-polyvinyl sulfate solution

V: Proper value of a sample of 1 / 400-polyvinyl sulfate solution (ml)

B: Proper value of blank test of 1 / 400-polyvinyl sulfate solution (ml)

S1: Sample amount collected (g) S2: Test solution amount collected (g)

Example 1

To 1 liter of low molecular weight chitosan (1% concentration in 1% lactic acid solution, the viscosity is 35 cps), add potassium permanganate (KMnO ₄ ) to 0.3 mg / 1 or less, and then evaporate the water while changing the temperature change from 70 ℃ to 90 ℃. When the contents are in the same gel state as starch syrup, the reaction is terminated, and distilled water is added to the total amount of 1 liter, and then filtered to make low molecular weight chitosan solution with less astringent taste and free amino acid. Got it.

The analysis results are shown in Table 1.

In the results shown in Table 1, the pH of the solution was not changed, the viscosity was 6%, and the chitosan recovery was 99%. The free amino group was slightly different depending on the temperature, but there was some loss at 90 ℃, which was negligible compared to other oxidants. On the other hand, the color of the obtained chitosan solution was slightly discolored in pale yellow color of the stock solution.

Example 2

To 1 liter of polymer chitosan (1% in lactic acid aqueous solution, viscosity is 2,400 cps), add potassium permanganate (KMnO ₄ ) concentration to 0.3mg / 1, and change the temperature to 70 ℃ ~ 90 ℃. When the contents evaporate to gel state like starch syrup, the reaction is terminated. Distilled water is added to the total amount of 1 liter, and the mixture is filtered to make low molecular weight chitosan solution with less astringent taste and free amino acid. Got.

The analysis results are shown in Table 2.

In the results shown in Table 2, the pH of the solution was not changed, the viscosity was lowered by 90%, and the chitosan recovery was 99%. The free amino group was slightly different depending on the temperature, but there was a loss of 2.5% at 90 ℃, which was negligible compared to other oxidants. On the other hand, the color of the obtained chitosan solution was slightly discolored in pale yellow color of the stock solution.

Example 3

To 1 liter of low molecular weight chitosan (1% acetic acid in aqueous solution, viscosity is 34 cps), add potassium permanganate (KMnO ₄ ) so that the concentration is 0.3mg / 1. When the contents are in the same gel state as starch syrup, the reaction is terminated, and distilled water is added to the total amount of 1 liter, and then filtered to make low molecular weight chitosan solution with less astringent taste and free amino acid. Got it.

The analysis results are shown in Table 3.

The results shown in Table 3 showed that the pH of the solution was unchanged, the viscosity was 6% lowered, and the chitosan recovery was 99%. The free amino group was slightly different depending on the temperature, but there was a loss of 2.5% at 90 ℃, which was negligible compared to other oxidants. On the other hand, the color of the obtained chitosan solution was slightly discolored in pale yellow color of the stock solution.

Example 4

To 1 L of low molecular weight chitosan (1% acetic acid in aqueous solution, 2,000cps in viscosity), add potassium permanganate (KMnO ₄ ) concentration to 0.3mg / 1, and change the temperature to 70 ℃ ~ 90 ℃. When the contents evaporate to gel state like starch syrup, the reaction is terminated. Distilled water is added to the total amount of 1 liter, and the mixture is filtered to make low molecular weight chitosan solution with less astringent taste and free amino acid. Got.

The analysis results are shown in Table 4.

In the results shown in Table 4, the pH of the solution was not changed, the viscosity was lowered by 87.5%, and the recovery of chitosan was 99%. The free amino group was slightly different depending on the temperature, but there was about 5% loss at 90 ℃, which was negligible compared to other oxidants. On the other hand, the color of the obtained chitosan solution was slightly discolored in pale yellow color of the stock solution.

Example 5

To determine whether the low-molecular chitosan solution obtained by the above process can be used as a sports drink, first mix the low-molecular chitosan solution and the exaggerated mixture with the spring water to be eaten (45 ℃), and then secondly, sodium citrate, potassium softened salt, purified salt, Calcium lactate and the like were mixed, and citric acid and vitamin C were mixed three times, and the concentrated fruit juice was mixed four times, and then sterilized and cooled at 100 ° C. for 10 minutes.

After cooling, the required fragrance was added to make a finished product. At this time, the mixing ratio is shown in Table 5.

Various sports drinks shown in Table 5 were colorless and refreshing, and as a result of tasting, the astringent taste that could appear when chitosan was added was hardly felt. However, the sour taste and chitosan's inherent taste continued after 2-3 minutes of drinking. This phenomenon shows the possibility of developing for adults as a property of chitosan-containing beverages.

As described above, the present invention dissolves chitosan in an organic acid, adds an oxidizing agent, and then treats it in a reaction tank under specific conditions to produce a chitosan-gel having a chewy gel form, such as starch syrup, and then dissolves it again in water to provide a unique astringent taste and bitter taste of chitosan. While reducing the color does not change and the amino group can be collected any low-molecular chitosan solution that remains a lot easier than the conventional method has the advantage of high yield and economical production.

Claims (4)

A specific oxidant is added to the chitosan solution in which chitosan is dissolved in an organic acid, and then treated in a reactor having a reduced pressure of 450 to 760 mmHg and a reaction temperature of 50 to 100 ° C. to form a chitosan-gel like starch syrup, which is then dissolved in distilled water. A method for producing a low molecular weight chitosan solution with less flavor and less residual amino groups. The astringent taste of claim 1, wherein the chitosan is dissolved in acetic acid or lactic acid solution, and then the oxidant is added to the reaction tank to change the reaction temperature to 70 to 90 DEG C, thereby reducing the viscosity of the chitosan to 10 cps to 1,500 cps. A method for producing a low molecular weight chitosan solution having a small amount of amino groups. The method for producing a low molecular weight chitosan solution according to claim 1 or 2, wherein the oxidizing agent is potassium permanganate (KMnO ₄ ) and its amount is 0.3 mg / l or less. The end point of decompression in the reactor is until the water of the chitosan is not completely removed (when the shape of the chitosan exhibits a gel phenomenon such as starch syrup), and at this moment, the pressure is released, and then water is added to gelate. The method for producing a low molecular weight chitosan solution having a small astringent taste and a large amount of amino group residues, including melting the chitosan again to make the total amount of the same amount as the first time, and using water as distilled water or drinking spring water.