JPH01228438A - Purification of crude sweetener extract - Google Patents

Abstract

PURPOSE: To efficiently refine a crude extract liquid from natural sweetener and to recover the objective dissolved solid content in a high recovery rate by treating a crude extract liquid of natural sweetener with chitosan and magnesia adsorbent. CONSTITUTION: A crude extract liquid is extracted from a cut product of a natural sweetener (e.g. stevia) with warm water at >=40 deg.C. Then chitosan is added by >=0.1wt.% of the dissolved solid content in the extract liquid so that the chitosan concn. in the extract liquid becomes >=500ppm, and the liquid is stirred and left to stand to flocculate and settle the suspended material and colored material. Then the settled material is separated and removed. To the obtd. extract liquid having 4.0 to 10.5pH, a magnesia absorbent is added to make the suspended material and colored material remaining in the liquid adsorbed. The liquid is neutralized and brought into contact with an ion exchange resin to make impurities adsorbed, and the liquid is spray or freeze dried.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a method for efficiently purifying crude extracts of natural products and recovering target dissolved solids at a high rate. Relating to a purification method.

(Prior art) Stevia, Luo Han Guo, Brazilian licorice, sweet tea, licorice, thaumatin, etc. have a unique sweet taste, and it has been proposed to utilize their sweetening effect (for example,
Special Publication No. 60-50798).

However, the raw material sweetening liquid contains organic and inorganic colloidal substances, cellulose compounds, slaked lime added to the raw refined sugar liquid, and other fine suspensions.
In addition, they exhibit significant coloration due to impurities, and it is necessary to separate these suspended matter from the raw sugar solution and obtain a clean sugar solution.

Conventionally, the purification of such a sugar solution involves (1) a method in which calcium chloride treatment is performed, followed by adsorption treatment with a porous resin, followed by crystallization, (2) a method in which the extract is subjected to ion exchange treatment, (3) ) A method of purifying by adsorption and removal using a magnesia-based adsorbent has been proposed.

(Problem to be Solved by the Invention) However, in the method (1) above, when the calcium content is excessive, some dissolved solid content adsorbs to the insoluble calcium content, resulting in a high recovery rate of the target sweet purified liquid. It has the disadvantage that it decreases. Method (2) is a good method when the impurity content is low. However, in the case of crude extracts with high impurity content, this method alone places an excessive load on the ion exchange resin.
The resin will become fatigued. Furthermore, in the case of method (3) using a magnesia-based adsorbent, the adsorption capacity of magnesia is not sufficient, so a large amount of magnesia is required, which is not economical, and the sugar solution accompanying the treated adsorbent causes a decrease in yield. There is a drawback.

(Means for Solving the Problems) As a result of extensive research to overcome the problems associated with the conventional purification of crude extracts, the present inventor has developed a method using chitosan for purifying crude extracts of natural sweeteners. It was discovered that the objective could be achieved by performing magnesia treatment after the treatment, and based on this knowledge, the present invention was accomplished.

That is, the present invention provides a method for purifying a natural sweetener-containing extract, which comprises adding chitosan to a crude extract of a natural sweetener and then treating the crude extract with a magnesia adsorbent.

The extract containing vine natural sweeteners to which the method of the present invention is applied is usually extracted from plants such as stevia, citrus fruit, and other plants containing sweetener ingredients, such as Brazilian licorice, sweet tea, and licorice.

Some are obtained by extracting thaumatin, etc. There are no particular restrictions on the extraction method itself, and any suitable method can be used depending on the type of plant. Usually, it is an extract obtained by extracting a cut amount of the sweet component-containing plant with warm water, preferably at a temperature of 40°C or higher.

First, chitosan is added to this extract. Chitosan is obtained from crab and shrimp shells by demineralization (acid treatment), protein removal, and deacetylation treatment, and has a molecular weight of several dozen to several million.
It is preferable to use one for use as an accompaniment, and those commercially available in powder form can be used. When using this, o, i
-Use as a 0.1 to 1.0% concentration solution in an acetic acid aqueous solution of o, s%.

The amount of chitosan added is usually 0.1% by weight or more, preferably 0.35 to 1.0% by weight, based on the dissolved solid content in the extract, and the chitosan concentration in the extract is 50 ppm.
Above, preferably it is in the range of 100 to 50,022 m.

Further, the pH is preferably in the slightly acidic to neutral range.

This chitosan treatment removes SS and extractable color components in the extract, and does not react directly with sweet components.

It selectively removes certain coexisting precipitated components and colored components by aggregation reaction, and has a removal effect unimaginable with conventional treatment methods. In this chitosan treatment, a chitosan solution is added to the extract, stirred, and left to stand still to coagulate and precipitate suspended matter and colored matter. If the amount of chitosan solution is too small, this coagulation and sedimentation will not be carried out sufficiently even if time is taken, and if the amount of chitosan solution is too large, although the sedimentation rate is fast, excess chitosan will remain in the solution, which will cause problems in the subsequent stage. Post-processing is required and the effect is saturated.

After this chitosan treatment, a conventionally known inorganic or organic flocculant may be used in combination. The combined treatment makes the flocs denser and improves filtration performance. As such flocculants, anionic polymer flocculants are preferable, such as sodium polyacrylate (for example, molecular weight of several hundred blades), alginic acid (trade name: Duck Acid A), etc., and the amount thereof is preferably controlled by chitosan. The range is 1 to 20%, preferably 5 to 10%. However, this process is selected as necessary.

A magnesia adsorbent is added to the extract obtained by separating and removing the flocculated precipitates generated in this chitosan treatment by filtration or centrifugation, and the remaining suspended matter and colored substances are further adsorbed by magnesia.

Next, a purified extract is obtained by filtration. As this magnesia, one previously developed by the present inventors is preferably used. This is, for example, magnesia particles obtained by firing a usable magnesia compound formed by thermal decomposition at a relatively low temperature of 450 to 600°C (Japanese Patent Application Laid-open No. 53-30489). One example is M-511, which is commercially available from Kunimine Kogyo Co., Ltd.

The magnesia adsorption treatment at this time can be carried out by various methods such as powder addition method, fluidized bed method, column flow method, etc. Either batch method or continuous method may be used. For example, adsorbent powder is added to the extract solution. Suspension contained therein by addition and mixing;
After adsorbing the chromaticity components, they are separated by sedimentation or flotation. In this case, an inorganic or organic flocculant may be used in combination, if necessary. The thus recovered solid matter is heated to about 400 to 600°C to burn off the adsorbed contaminants, and then it can be used again as an adsorbent.

The initial pH of this magnesia adsorption treatment is usually 4.0 to 10.
．． 5, preferably 5.0 to 9.0.

After the magnesia adsorption treatment, the extract is neutralized and subjected to the next finishing treatment.

In the method of the present invention, by combining chitosan treatment as a first-stage treatment and magnesia adsorbent treatment as a second-stage treatment,
By reducing the amount of magnesia adsorbent added, it is possible to (1) improve impurity removal efficiency and (2) reduce processing costs.

Since the sweetener-containing crude extract targeted by the present invention is a natural product, suspended matter, dissolved impurities, and color components exhibit a wide distribution from large molecular sizes to very small low molecular weight components. There is.

Even if such impurities are attempted to be removed by chitosan treatment alone, only those with large molecular weights will be removed, and even if the amount of chitosan added is increased, the degree of purification of the target extract cannot be increased. In addition, magnesia alone has insufficient adsorption capacity and only adsorbs substances with low molecular weight, and the filtration rate of flocs produced by agglomeration is poor, resulting in sludge from which dissolved solids containing a large amount of sweeteners are removed by filtration. This has the disadvantage that the recovery rate of the target sweetener-containing solids is significantly reduced.

As an embodiment of the present invention, there is a method in which the first and second stages of treatment are not performed in separate reaction tanks, but in the same tank. In this case, adsorption treatment is performed by adding a magnesia adsorbent into a reaction tank in which impurities have been flocculated and precipitated through the chitosan treatment in the previous stage. This method is most preferable in terms of efficiency.

In addition, the coagulated sediment (sludge) in the first and second stages can be used as feed (containing protein), fertilizer, regenerated adsorbent, etc., so in this sense, the first and second stages are treated as 9.
The reaction may be carried out using 11 reaction vessels.

In the method of the present invention, it is preferable to further perform a finishing treatment if necessary. Any conventionally known method may be used for this finishing treatment, but usually a strongly acidic cation exchange resin, a weak iL! Impurity adsorption treatment using an ion exchange resin such as a basic anion exchange resin is preferably used.

In such a case, for example, the aqueous solution is passed through a porous adsorption resin column to selectively adsorb sweet components, then the sweet components are eluted with 80% methanol to remove residual impure colored components, and then strong acid The cations in the liquid are exchanged with hydrogen ions using a basic cation exchange resin, and then purified using a weakly basic anion exchange resin. Alternatively, residual cations are ion-precipitated using a strongly acidic cation exchange resin in the aqueous solution state, and then sweet components are purified using a weakly basic anion exchange resin. Finishing treatment can be done in one of several ways.

The extract is then sprayed or freeze-dried to obtain the desired purified sweet powder. At this time, it is preferable to add dextrin or the like in an amount of 100 to 50% by weight based on the solid content. Incidentally, such powdering is not necessarily essential, and it goes without saying that it may be used as it is or after being concentrated as a syrup.

The sweetness components in such purified extracts may vary depending on the type of sweetener-containing plant, or may include stevioside (S-5 site, S-4 site, glycyrrhizin and its analogues, etc.),
Rebaudioside A, C.

Contains D, E, glucoside, and fructose as a mixture.

Next, the present invention will be explained in more detail based on examples.

Example 1 300071i of tap water was added to 171 g of Stevia raw leaves, and extraction was carried out at 65 to 70°C for 3 hours while stirring. 6. Next, 3 volumes of this extracted stock solution were filtered, and the residue was further squeezed to obtain 2. 600ml was obtained. This is 2.27% dissolved solids.
, the absorbance (410 nm) was 13.5% pH 7.

Add a 0.2% chitosan solution (0.2% acetic acid) to this crude extract at room temperature.
2%) was added to give a chitosan concentration of 100 ppm, mixed rapidly for 10 minutes, and then
The chitosan-added solution was stirred gently for ~20 minutes and left for 30 minutes.Then, this chitosan-added solution was filtered through Toyo Filter Paper No. 5A, and the dissolved solid content of this filtrate was 1.93%, and the absorbance (410 nm)
, 8.5.

Next, add 40 to 1 part magnesia to this filtrate based on the solid content.
00% by weight was added. Add magnesia to 60°C.
The mixture was added over about 5 minutes while stirring with a stirrer, and stirring was continued for 30 minutes.

After the addition is complete, adjust the solution to pH 10.3 with 2N sodium hydroxide.
The magnesia additive solution adjusted to
After filtering through 5A and adjusting the pH to 7.0 with %N hydrochloric acid, absorbance (λ=410 nm) and solid content concentration were measured. The relationship between the amount of magnesia added and the absorbance at this time is shown in FIG.

Example 2 A purified extract was obtained in the same manner as in Example 1, except that filtration after the addition of chitosan was omitted and 40 to 100% by weight of magnesia and 10 ppm of sodium polyacrylate were directly added to the treatment tank (so-called - tank treatment). The results of measuring the absorbance of the purified extract thus obtained are shown in FIG.

Comparative Example 1 A purified extract was obtained in the same manner as in Example 1, except that the Stevia raw leaf extract was directly treated with magnesia without being subjected to the chitosan treatment. The relationship between the amount of magnesia added and the absorbance of this product is shown in FIG. From the same figure, even if magnesia is added in an amount of 50% by weight based on the dissolved solid content, the absorbance is high, and even if it is added in an amount of 100% by weight, an absorbance of about 1.5 to 2 remains.

Comparative Example 2 The amount of chitosan added to the crude extract (absorbance 13.5) obtained by hot water extraction of Stevia leaves in exactly the same manner as in Example 1 was increased to 200 ppm, and the absorbance was 7.0. No rapid decrease was observed. However, the dissolved solids content after removal of aggregates decreased to 1.85%. The relationship between the amount of chitosan added and the dissolved solid content is shown in FIG.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing the relationship between the amount of magnesia added and absorbance after chitosan treatment of the crude extract, Figure 3 is a graph showing the relationship between the amount of magnesia added and absorbance, and Figure 4 is a graph showing the relationship between the amount of magnesia added and absorbance. It is a graph showing the relationship between the amount of chitosan added and the dissolved solid content. Patent Applicant: Teak Resources Ltd. Masaaki Ikari Agent: Patent Attorney: Ii 1) Toshizo 1 Figure Mg0 (S) Mg0 (S) Mg0 Addition amount of f-chitosan (ppm)

Claims (1)

[Claims] (1) A method for purifying a crude extract of natural sweets, which comprises treating the crude extract of natural sweets with chitosan and then using a magnesia adsorbent.