The present invention relates to a method for producing a chitosancontaining salt having the function of lowering blood pressure. The method comprises the steps of: (a) dissolving an acid-soluble chitosan in organic acid, or dissolving a water-soluble chitosan derivative in water, to prepare a chitosan solution; (b) spraying the chitosan solution on salt particles to bind the chitosan to the salt particles; and (c) drying the chitosan-bound salt particles. According to the present invention, the chitosan or its derivative is bound to the salt particles by spraying or mixing such that the chitosan-containing salt can be produced without performing a recrystallizing step. Thus, the production cost of the chitosan-containing salt can be significantly decreased.

Description of the Invention

TECHNICAL FIELD

The present invention relates to a method for producing a chitosan-containing salt having the function of lowering blood pressure, the method being characterized by binding chitosan or its derivative to salt particles. More particularly, the present invention relates to a method for producing a chitosan-containing salt, which comprises dissolving an acid-soluble chitosan in organic acid or dissolving a water-soluble chitosan derivative in water, to prepare a chitosan solution, spraying the chitosan solution on salt particles to bind the chitosan or its derivative to the salt particles, and drying and finely grinding the chitosan-bound salt particles.

BACKGROUND ART

Patients with cardiac vascular diseases, such as hypertension, or adult diseases, hard to cure, such as diabetes and renal failure, are recommended to limit salt or to take a small amount of salt. As salt which may be given to a patient with hypertension, there is now only salt whose sodium chloride (NaCl) content is reduced by adding potassium chloride (KCl). Even a functional salts, there are only garlic salt and green tea salt whose clinical results have not yet been found.

Hypertension is mainly described by a physiochemical mechanism caused by renin-angiotensin, and substances capable of inhibiting the activity of angiotensin converting enzyme (ACE) are currently of high concern for direct inhibition of hypertension. In addition to producing dipeptide, ACE is presumed to show an enzyme reaction mechanism similar to pancreatic carboxypeptidase A. On the basis of this presumption, chemically synthesized ACE inhibitor, such as captopril and enarapril, are used as antihypertensive agents. However, since such chemical products have many problems, such as safety, side effects, and the like, the searching of peptide-based ACE inhibitory substance from various natural substances is being continued.

Steady intake of food containing the ACE inhibitory substance will help the prevention or alleviation of hypertension. Chitosan is one of the biopolymer substances, prepared by deacetylating chitin which a kind of animal polysaccharides, present in the shell of shellfish, such as crabs or lobsters, and is known as the ACE inhibitory substance. Chitosan is a polysaccharide linked by .beta.-1,4-bond of D-glucosamine, and includes .alpha.-chitosan derived from shellfishes, .beta.-chitosan from molluscs, and .gamma.-chitosan from microbial strains.

Strictly speaking, chitosan can be defined as a chitin derivative, and acid-soluble chitosan is generally called "chitosan". Examples of water-soluble chitosan include CM-chitosan (carboxymethyl-chitosan which carboxymethyl group is given by a chemical numerical formula), S-chitosan (oligosaccharide-chitosan), SCM-chitosan (N-sulfide derivative of N-deacetylated CM chitin), HP-chitosan (hydroxyl-propyl-chitosan), etc. Also, according to molecular weight, monosaccharide is called "glucosamine", a complex of 2.about.9 monosaccharides is called "oligochitosan", and a complex of more than 10 monosaccharides is called "chitosan".

To make patients with hypertension or diabetes, avoid excessive intake of salt with low purity, such as a mixture of potassium chloride (50%) and sodium chloride (50%), has appeared, but its effect on hypertension has not been proved yet.

Meanwhile, Korean patent publication 95/5196A disclosed a liquid salt seasoning comprising a mixture of salt and chitosan. However, this patent application has no mention of a blood pressure lowering efficacy, and also has problems that it is not easy to mix seasoning liquid with 1.about.3% of chitosan, since it is difficult for chitosan generally being participated in alkaline water due to having an isoelectric point of pH 6.5, to be dissolved, and chitosan with a high-molecular weight is in a gel form even in acetic acid due to its high viscosity.

Furthermore, methods for producing chitosan salt are known, in which chitosan dissolved in organic acid is mixed with salt solution, and the mixture is subjected to stirring, evaporating, drying and crystallizing steps (Korean patent publication KR 01/00706A and KR 01/103538A). However, KR 01/103538A has no mention of the blood pressure lowering efficacy of the chitosan salt. KR 01/00706A suggests the blood pressure lowering efficacy of the chitosan salt, but has a problem that it requires the recrystallizing step so that production process is complex and a great increase in production costs is caused upon the mass production of the chitosan salt.

DISCLOSURE OF INVENTION

The present inventors have conducted many researches to solve the above-mentioned problems occurring in the prior art, and consequently, found that when a solution of chitosan is sprayed on salt particles to bind the chitosan to the salt particles, chitosan-containing salt having a blood pressure lowering function can be economically produced without performing a recrystallization process. On the basis of this discovery, the present invention was perfected.

Accordingly, an object of the present invention is to provide a method for producing chitosan-containing salt, which can produce the chitosan-containing salt by a simplified process at significantly decreased costs.

To achieve the above object, the present invention provides a method for producing a chitosan-containing salt having the function of lowering blood pressure, which comprises the steps of: (a) dissolving an acid-soluble chitosan in organic acid, or dissolving a water-soluble chitosan derivative in water, to prepare a chitosan solution; (b) spraying the chitosan solution on salt particles to bind the chitosan to the salt particles; and (c) drying the chitosan-bound salt particles.

The chitosan used in the step (a) of the inventive method is preferably .alpha.-chitosan or .beta.-chitosan. Also, the chitosan or its derivative used in the step (a) has preferably a molecular weight of 10.about.100 kDa. The content of the chitosan or its derivative in the chitosan-containing salt is preferably 1.5.about.5%.

Moreover, the organic acid used in the step (a) preferably is lactic acid, acetic acid or ascorbic acid, and the salt used in the step (b) is preferably natural sea salt, refined salt or rock salt, which has the size of 10.about.50 mesh.

In a preferred embodiment of the present invention, natural sea salt produced in Korea is processed. Meanwhile, low-molecular weight chitosan is dissolved in an aqueous solution of organic acid (lactic acid, acetic acid or ascorbic acid), or a chitosan derivative is dissolved in water, to prepare a chitosan solution.

The chitosan solution is bound to the processed salt particles by a spraying or mixing process. The chitosan-bound salt particles are dried to produce a chitosan-containing salt. As the chitosan used in this embodiment, .alpha.-, .beta.- or .gamma.-chitosan may be used, but the .alpha.-chitosan which is produced at large amounts and at a low cost is suitable.

The molecular weight of the chitosan is not specially limited. However, a chitosan having a molecular weight of 0.5.about.500 kDa is preferred since it shows good binding force to the chlorine ion of salt. A chitosan having a molecular weight of 10.about.100 kDa is more preferred since it is soft and has a good taste after intake without lowering the properties of salt. The chitosan content in the chitosan-containing salts is preferably 0.05.about.5%, and more preferably 1.5.about.5%. If the chitosan content is less than 1.5%, the blood pressure-lowering function of the chitosan-containing salt will be insufficient, and if the chitosan content is more than 5%, the taste of the chitosan-containing salt will be lessened due to an acrid taste of the chitosan. In addition, both the water-soluble chitosan and the acid-soluble chitosan may be used in the present invention.
 

Claim 1 of 7 Claims

1. A method for producing a chitosan-containing salt having the function of lowering blood pressure, which comprises the steps of: (a) dissolving an acid-soluble chitosan in organic acid, or dissolving a water-soluble chitosan in water, to prepare a chitosan solution; (b) spraying the chitosan solution on salt particles to bind the chitosan to the salt particles; and (c) drying the chitosan-bound salt particles.

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