JP2743281B2 - Method for producing arabinogalactan - Google Patents

Description

The present invention relates to a method for producing arabinogalactan.

Arabinogalactan is a neutral polysaccharide having β-D (1-3) -galactose as a main chain and arabinose as a side chain, and is abundantly contained in plants, particularly larch trees. Arabinogalactan is readily soluble in cold water, and its aqueous solution has extremely low viscosity, excellent pH stability and coexisting salt stability, and is widely used in various industries, mainly in the food field.

[Conventional technology]

To produce arabinogalactan, usually larch sawdust or chips are immersed in cold water, water-soluble components are extracted, insoluble components are removed by excess, and phenolic substances such as tannic acid and lignin are removed. Methods of removing, dehydrating, and drying into powder are known. When phenolic substances such as tannic acid and lignin remain, the product is colored yellow-brown, and when used for food, it causes bitterness and woody odor, which is not preferable. For this reason, at present, highly purified arabinogalactan with a low residual amount of phenolic substances has been awarded.

Generally, phenolic substances are considered to be pseudo-bound by interaction with arabinogalactan,
As a purification method, phenolic substances are oxidatively decomposed with an oxidizing agent such as ozone or hydrogen peroxide, and then adsorbed using an ion-exchange resin or activated carbon (Mizumi, Abstracts of the 38th Annual Meeting of the Japan Wood Science Society) ) And a method of coprecipitation removal using active magnesium oxide (US Pat. No. 3,325,473).

[Problems to be solved by the invention]

For purification with active magnesium oxide, usually, magnesium oxide is added to the extract, and the mixture is heated and stirred at about 60 ° C for 30 minutes.
~ 60 minutes, after co-precipitation of phenol, it is performed in the step of separating the liquid and the precipitate with a centrifuge,
If the residual phenol is sufficiently purified to 1.0 mg or less per 1 g of solids, active magnesium oxide must be added at least 0.4 g to 1 mg of phenol present in the solution before purification, resulting in a large amount of added phenol. Disadvantageous. In addition, a solid-liquid separation step is required after co-precipitation, so that the number of production processes increases and productivity is reduced.

Further, purification with an oxidizing agent such as ozone or hydrogen peroxide is usually carried out in a process of reacting these oxidizing agents with an extract and then adsorbing the oxide with an ion exchange resin or activated carbon. The solid component
When purifying enough to 1.0 mg or less per 1 g, ozone treatment requires 5 mg ozone per 1 mg of phenol,
In order to produce high-purity arabinogalactan in large quantities, the scale of equipment becomes large. Further, in the hydrogen peroxide treatment, a 35% hydrogen peroxide solution must be added in an amount of 0.9 g or more per 1 mg of phenol. In addition, post-treatment requires adsorption of an oxide by an ion-exchange resin or activated carbon, which complicates the process and requires maintenance such as regeneration, so that production efficiency cannot be improved.

The present invention provides a method for efficiently producing high-purity arabinogalactan.

[Means for solving the problem]

The present inventors have studied a method for efficiently producing high-purity arabinogalactan, and as a result, it was generally thought that arabinogalactan and phenol were quasi-bonded due to the interaction, The inventors have found that phenolic substances can be separated by entraining them in water on the permeate side using an outer membrane, and completed the present invention.

The present invention is a method for producing arabinogalactan, which comprises extracting arabinogalactan from the woody part of a tree of the genus Larix and removing impurities contained in the extract using an ultraperm membrane.

In carrying out the present invention, arabinogalactan is first extracted from the woody part of a tree of the genus Larix.

As the woody part of larch trees, larch sawdust or chips are usually used. As an extraction method, the woody part may be immersed in preferably four times or more of water. The immersion time is 10 to 60 minutes, usually about 30 minutes. It is preferable to stir the immersion liquid. The immersion temperature may be room temperature, and no particular effect is recognized even if the immersion temperature is increased.

It is preferable to remove insoluble components by a conventional method before treating the extract using an ultraperm membrane. As a removal method, a super-aid is added to the extract, and the insoluble portion is removed by a filter press or a vacuum filter, or the insoluble portion is removed using paper or the like without adding the super-aid. It may be removed.

Next, impurities contained in the extract are removed by using an ultra-membrane.

Examples of the material of the ultramembrane include polyolefin, polyamide, and polysulfone. As the membrane form, a flat membrane type, a spiral type, a tubular type, a hollow fiber type and the like are used. Hollow fiber types have particularly good processing capabilities. The molecular weight cut off of the membrane is around 4000-23000. If the molecular weight is higher than this, high-molecular-weight arabinogalactan flows out, and if it is lower than this, a sufficient permeation flow rate cannot be obtained. Any material can be used as the ultra-permeation membrane as long as it has the above-mentioned molecular weight cut-off range.

Concentration magnification by ultra-membrane is 5 times or more, preferably 10 to
30 times. If the concentration ratio is lower than this, impurities cannot be sufficiently separated. If the concentration is increased by a factor of 30 or more, the permeation flow rate decreases, and the production efficiency deteriorates. If water is added to the concentrated solution and further concentrated, the separability of impurities is improved.

For example, the relative concentration of impurities in the 10-fold concentrate is reduced to about 1/5, and almost no arabinogalactan outflow is observed. When water is added to the concentrate and concentrated again, the relative concentration of impurities is reduced to about 1/25.

If necessary, the concentrated liquid may be further purified by magnesium oxide, ozone, hydrogen peroxide or the like.

Next, the concentrate obtained by the ultra-permeation treatment is dehydrated and dried. Spray drying, freeze drying, vacuum drying, solvent precipitation, and the like can be used as the dehydration drying method. These methods may be used in combination.

〔The invention's effect〕

According to the method of the present invention, purification can be carried out more easily and with a smaller facility than in the conventional method, and a large amount of purified arabinogalactan with higher purity than before can be produced. Furthermore, by performing concentration simultaneously with separation of impurities, the load of the drying step can be reduced.

Example 1 60 kg of larch sawmill sawdust was mixed with 300 parts of water,
After performing extraction with stirring for a minute, sawdust was separated by a strainer to obtain an extract 240. 4 kg of diatomaceous earth aid
Was added, and the mixture was passed through a filter press to obtain 220 liquid.

When this liquid 10 is dried with a spray drier, 100 g of powder is obtained.
It was 7.0 mg / g as measured by the n-Denis method.

The above solution 120 was manufactured by Nitto Denko Co., Ltd.
Pressure of 3.0k using a 50 capillary type module
Separation treatment was performed up to a concentration ratio of 10 times under the conditions of g / cm ² and a circulation flow rate of 100 / H. The concentrated liquid 10 was dried with a spray dryer to obtain 900 g of a product. The total phenol content of this product is 1.7m
g / g.

Example 2 Ion-exchanged water was added to the concentrate 10 obtained in the same manner as in Example 1.
After adding 110 and mixing, the mixture was again processed to the concentration magnification of 10 times using the same ultrapermembrane (fraction molecular weight: 20,000).
The liquid after the treatment was dried with a spray dryer to obtain 900 g of a product. The total phenol content of this product was 0.3 mg / g.

Example 3 The solution 120 before concentration obtained in the same manner as in Example 1 was subjected to pressure of 15.0 using a tuber-type module using an ultra-super membrane DUS-K5 (fraction molecular weight: 5000) manufactured by Daicel Corporation.
Under a condition of kg / cm ² and a circulation flow rate of 100 / H, separation and concentration were performed up to a concentration ratio of 10 times. This concentrated liquid 10 was spray-dried to obtain 50 g of dry powder. The total phenol content of this product was 1.9 mg / g.

Claims (1)

(57) [Claims] 1. A method for producing arabinogalactan, comprising extracting arabinogalactan from the woody part of a tree of the genus Larix and removing impurities contained in the extract using an ultraperm membrane.