JPS6336754A - Production of fructose syrup - Google Patents

Abstract

PURPOSE:To produce a fructose syrup having high content of fructose and fructo-oligosaccharide and low glucose content and usable as a sweetener for the patient of diabetes, by hydrolyzing inulin. CONSTITUTION:An aqueous solution containing about 5-10% inulin is produced from the tuber of Jerusalem artichoke or the rhizome of chicory. The solution is heated at about 40-70 deg.C, passed through a column filled with a strongly acidic cation exchange resin and optionally added with an acid to obtain an effluent having a pH of about 2.0-3.0. The effluent is heated at about 70-100 deg.C to effect the partial or complete hydrolysis, optionally treated with activated carbon or granular charcoal and passed through a column filled with a weakly basic anion exchange resin to obtain an effluent having a pH of about 6.5-7.0. The effluent is concentrated by evaporation, reverse osmosis membrane treatment, etc., to obtain a syrup containing a fructo-oligosaccharide and having a solid concentration of about 40-70%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing olibolraftanes and the resulting olibolraftane mixture, such as fructose syrup.

Prior Art and Problems to be Solved by the Invention Previously, starch conversion syrups were produced by hydrolysis of starch.

These starch-converted syrups, such as corn syrup, naturally contain D-glucose, maltose, and small amounts of oligoglucan and dextrin. The amounts of these compositions will vary depending on various factors. Fructose, known as an isomer of glucose, may also be produced by conversion of glucose, such as isomerization.

It is also well known that hydrolysis of syrups containing sucrose produces an equal mixture of fructose and glucose known as invert sugar. Sucrose is converted to invert sugar to produce industrially an amorphous syrup known as yellow syrup or molasses.

Fructose is also widely distributed in nature. Fructose has 7-lanose type and pyranose type, and furanose type accounts for about 20% in an aqueous solution at 20°C.

Crystalline fructose shall be 1.8 times sweeter than sucrose.
enberger et al.* Sugar Chea+1st
ryy 116 pagestthe AV I Public
shing Company+ Inc, * (19
83)). Therefore, fructose is considered the most common sweetener because its strong sweet taste can lower the calorie content of foods and beverages. Furthermore, fructose is superior to sandal sugar for food use in that it does not crystallize easily. Since human metabolism does not depend on insulin, it can be used as a sweetener for diabetics.

Recently, there are many synthetic sweeteners, but these require animal testing to determine their carcinogenicity. Therefore, fructose, which is a completely low-calorie natural product, has important significance as a sweetener.

While sucrose and glucose have been produced on a large scale as an energy source and for industrial use, the industrial use of fructose has been very limited due to the lack of methods to produce high-fructose products. pharmaceuticals, food, beverages,
Even when used as a therapeutic food, products with low fructose content (approximately 42-55% fructose) are not preferred. Preferred is a "high fructose syrup," which is either pure fructose or a concentrated aqueous solution containing small amounts of carbohydrates other than fructose, and more preferably purified fructose crystals.

Another industrial use of fructose is its conversion to mannitol. Mannitol is currently produced from invert sugar, but with this method, 3 parts of sorbitol is produced as a by-product to obtain one part of mannitol.
If pure fructose is used, only a portion of the by-product sorbitol will be produced.

Various methods have been reported for preparing syrups that are sweeter than starch-converted sugars.

The alkali isomerization reaction of D-glucose, D-mannose, and D-fructose is a long-known method, and its discovery (Recl, Trav, Chim, Pa.
ys-Bas 1st 4,203/1895 and 11th-0
92/1896) and thereafter, “Lobry de Bruy
n-van Ekenstein Conversion
” is summarized in.

It has been established that glucose can be isomerized with catalysts such as sodium hydroxide, sodium carbonate, calcium hydroxide, alkaline earth metal salts, alkaline ion exchange resins, ammonia, and pyridine, but the fructose content is approximately 1
The actual fructose yield was 0 to 30% and difficult to purify, resulting in a further decrease in the actual fructose yield.

An improved method for alkaline isomerization in the presence of borate (Me
ndicino, J, Am, CheI+1. S
oc, 82.4975/1960) was also discovered, but industrialization was difficult and it was not put into practical use.

Lobry de Bruyn, W, A, van E
Various patents have been disclosed that improve upon the method discovered by John Kenstein.

For example, Canadian Patent 488.178 (
1952), Canadian patent 694,539 (1964) for isomerizing glucose in the presence of an alkali metal aluminum salt to obtain fructose in high yield, Canadian patent 86 for producing fructose together with glucose from sucrose.
8,346 (1971), Canadian Patent 89 for a method for effectively separating fructose from invert sugar and high fructose sugar.
8.246 (1972), and Canadian Patent No. 1,146,102 (1983) for a process for producing fructose from a starting material containing seven lactofuranosides.

Another method for producing fructose is to separate fructose from the conversion reaction product by chemical precipitation.

This method works because fructose complexes are more insoluble in water than glucose complexes.

This chemical precipitation method initially looked very promising. Hydrolysis of sucrose produces equal amounts of fructose and glucose. Various acids were investigated to decompose the complex and liberate fructose, and carbonic acid was found to be the most effective. Carbonic acid liberates fructose and precipitates as calcium carbonate, which can be removed by filtration.

However, this precipitation method has not been put to practical use as a method for producing pure flux. There are several reasons for that. For example, even when carried out at low temperatures, there is a drawback that colored components are generated due to decomposition.

There are patents that separate fructose by taking advantage of the property that glucose is easily oxidized to glufonic acid by bromine or iodine, but the halogens used are expensive (U.S. patent
2,567.060).

+ Sucrose can be hydrolyzed with H-type cation exchange resin, but
In order to completely hydrolyze it, it is necessary to hold it in the resin for a long time, and it has the disadvantage of becoming colored at high temperatures and for a long time. A similar phenomenon occurs when the acid radicals are removed using a basic resin after decomposition with a mineral acid.

Ion exchange resins are also used to purify aqueous glucose solutions prior to isomerization reactions.

Examples of this are Canadian Patent No. 525.394 (1966) for a method for clarifying sugar solutions, and Canadian Patent No. 756.575 (1966) for a method for separating fructose and glucose.
967), Canadian Patent 1゜156.951 (1983) for the isomerization process from glucose to fructose,
Canadian Patent 771,127 (1967) for a process for obtaining pure fructose from sucrose or invert sugar; Canadian Patent 813 for a process for producing invert sugar from molasses;
297 (1969), Canadian patent 918゜150 (
1973), Canadian Patent No. 963°899 (1975) concerning a method for purifying a fructose solution obtained by an enzymatic method
), etc. are known. Further, U.S. Patent No. 3,04 of Dow Chemical Company, which uses a cation exchanger to chromatically separate the alkaline earth metal salt of invert sugar into glucose and fructose.
4,904,3゜044.905.3,044,906
There is also.

Pond's method involves enzymatic conversion to fructose. Marshall's pioneering U.S. patent 2.950,22
From 8 onwards, there are many things related to isomerization by enzymes.

Enzymes from various microorganisms have been developed to convert glucose into glucose and fructose. For example, Pseudomonas, LacLo
bacillus, Escherichiat
Aerobacter Bacillus etc., namely Aerobacter cloacae,
Glucose isomerase (ES 5,3.L 5) is used for the isomerization of Baa glucose to fructose.

Thus, according to the prior art, starch is first liquefied;
It is then saccharified by enzymes, or liquefaction and saccharification are performed simultaneously by enzymes.

There are also many patents related to such enzymatic methods. For example, U.S. patent Re, 28,885 for the production of isomerized glucose syrup by glucose isomerase; British patent for classification of actinomycetes that produce glucose isomerase 1,
103,394 and Japanese Patent 7428 (1966)
, Canadian patent for enzymatic isomerization of starch hydrolysates
986,866 (1976), Canadian patent 947,217 for a method for enzymatically producing oligosaccharides from starch.
(1974), Canadian Patent No. 1,106,225 (1
981), Canadian patent for producing fructose polymers by enzymatic fructose transfer from sucrose 1,11
7.047 (1982) is known.

As mentioned above, it can be seen that fructose, which is rich in sweetness and highly useful, has been expensive until now.

Only a small amount of plant fructans, typified by inulin obtained from Jerusalem artichoke, dahlia, etc., can be obtained by acid hydrolysis. It is known that D-fructose and D-glucose can be obtained by acid decomposing inulin represented by the following formula and adding alcohol.

It has been reported that dietary fructose has physiological effects, and Japanese experiments have shown that fructooligosaccharides (GF2-4) have two effects. That is, when glucose syrup containing oligosaccharides was administered to hyperlipidemic patients for 5 weeks, serum cholesterol and blood pressure were significantly lowered. When administered to geriatric patients for two weeks, the amount of bifidobacteria increased to the level of healthy young people (the amount of bifidobacteria normally decreases with aging). Bifidobacteria assimilate these oligosaccharides, which cannot be digested by humans, resulting in the production of lactic acid and acetic acid, which lowers the pH in the intestines. Increased pH in the intestines is associated with aging and is also associated with the formation of nitrosamines, which are thought to be carcinogenic.

Because oligosaccharides have such useful physiological effects, Meiji Seika has already produced sugar mixtures containing oligosaccharides enzymatically from sucrose. Its average composition is as follows.

Monosaccharides (mainly glucose) approximately 37% Sucrose (GF) approximately 11% GF 2
About 24% GF, about 23% GF, about 5% The sweetness of this sugar composition is about 60% of sucrose.

In order to produce sweet syrups using such conversion reactions, it is necessary to remove and control unnecessary by-products and colored products.
The current situation is that no practical solution has been established to date.

Although the conventional continuous production method using immobilized glucose isomerase has certain advantages, it has the disadvantage that the enzyme is deactivated. Furthermore, although enzymatically produced fructose is relatively pure, it still requires purification such as decolorization and desalting.

Steps to Solve the Problem The present invention aims to provide a practical manufacturing method for converting inulin to fructose. The present invention provides a method for producing sweet syrups without creating problematic colors or odors. The present invention further provides, during the conversion reaction,
We provide a manufacturing method that does not require inert gas or alkali,
Furthermore, improved sweetening syrups can be produced and a new and improved method for producing syrups containing fructooligosaccharides is provided.

A method for hydrolyzing inulin to produce a syrup containing fructooligosaccharides is provided by the present invention. The method consists of the following operations.

(a) Obtain an aqueous solution containing inulin. (b) By passing an inulin aqueous solution through a strongly acidic cation exchange resin column at about 40 to 70°C, the pH of the effluent becomes about 2 to 3. (C) Hydrolyze the effluent by heating it to a temperature of about 70-100°C. (d) When the hydrolyzate is passed through a weakly basic anion exchange resin column, the pH of the effluent is about 6.5~? ,
Becomes O. (e) Concentrate the effluent so that it contains less water.

By carrying out the method of the present invention, the composition is between 0 and 100
% monosaccharides and 100-0% fructooligosaccharides and a solids content of about 40-70% fructose can be produced.

The present invention is constituted by features 1 to 17 shown below.

1. Obtain an aqueous solution containing inulin from Jerusalem artichoke tubers and chicory rhizomes.

2. The aqueous solution contains about 5-10% (W/W) inulin.

3. Add crushed Jerusalem artichoke tubers and chicory rhizomes to water and heat at about 80-100°C for about 20-30 minutes to obtain an inulin aqueous solution.

4. An aqueous solution containing inulin is recovered by pressing or filtering the hot water pulp mixture of crushed tubers and rhizomes.

5. Warm inulin aqueous solution has a temperature of about 40~70°C.

+ 6. The cation exchange resin is a sulfonic acid type H type.

7. Adjust the pH of the liquid passed through the cation exchange resin to about 2°0-2.
．． Adjust to 5.

8. When the pH is about 2.5, the partial hydrolysis is about 100
℃ for about 2.5 minutes.

9. When the pH is about 2.5, the partial hydrolysis is about 100
℃ for about 5.0 minutes.

10, when I]H is about 2.5, complete hydrolysis is about 1
00°C for about 15.0 minutes.

11. Treat the thermally hydrolyzed liquid with activated carbon before passing it through a column of weakly basic ion exchange resin.

12. Anion exchange resin is a porous weakly basic resin with oH
It is a type.

13. Concentrate the syrup to approximately 40-70% solids.

14. Concentrate the syrup to approximately 70% solids.

15. Concentration is carried out by performing vacuum evaporation and reverse osmosis, or by performing reverse osmosis and then vacuum evaporation.

16.Heating is preferably about 70℃ to improve thermal efficiency.
It is carried out by sending the liquid through a coiled tube maintained at a temperature of ~100°C.

17. By carrying out the method described above in this invention, a syrup having the following composition can be obtained.

Glucose approx. 4.6. -y luctose approx. 16.4°F2
Approximately 44.9. F, about 11.9. F, syrup with a composition of about 6.0° and other 7.6%, or glucose about 7
．． 2. Fructose approx. 26.2°F2 approx. 38.1. F,
About 8.1. F, about 6.6. F, about 4.6. Others 9.3
Syrup with a composition of %, or glucose about 13.5
．． Fructose approx. 45°1, F2 approx. 36.7. F3 approx. 3
．． 3. F, about 1.6. F.

Approximately 0.6. Other syrups with a composition of θ% or glucose of about 22.1. Fructose approx. 63°8, F2 approx. 12.1. F, 0. F, O, F, 0. Other approximately 2.0%
Syrup with the composition.

The syrup obtained by the method of the present invention, for example by partially or completely hydrolyzing inulin obtained from Jerusalem artichoke tubers, has a high fructose and fructooligosaccharide content and a low glucose content. This syrup is sweeter than prior art syrups and is used as a sweetener for diabetics.

Also, because of the lower sucrose content, the present syrup is expected to be more palatable than prior art syrups.

Jerusalem artichoke, a wild Canadian plant, grows well in cold regions and on degraded land, and its tubers store high yields of inulin. (One hectare produces about 8 tons of inulin.) As mentioned above, inulin is a polysaccharide with 2 to 35 fructose molecules attached to the glucose end, and is abbreviated as GF2-3. Write.

A polymer containing fructose, IF (1-β-fruc
to furanosyl) n-I 5ucros
e (abbreviated as GFn) is widely present in plants. Fructooligosaccharides (GF2-4) are present in many vegetables, such as asparagus, lettuce, onions, and oatmeal. As already mentioned, a polysaccharide (GF) consisting of 35 many fructose is called inulin.

Inulin is present in the tubers and rhizomes of Jerusalem artichoke, chicory, and dahlia. Inulin is tasteless and indigestible by humans.
Jerusalem artichoke tubers have been used as food as a vegetable.

Jerusalem artichoke tubers are ideally harvested in late October and processed within 2-3+ months (as their inulin content decreases during storage).

According to the invention, inulin from Jerusalem artichoke tubers is the preferred raw material, but it is also prepared in a similar manner from chicory and dahlia rhizomes.

Effects of the Invention According to the invention, a sweetened "fructose" syrup containing oligofructans is produced by partial hydrolysis of inulin. Inulin hydrolysis in this production method is catalyzed by hydrogen ions (H) generated from a cation exchange resin (H type) during the removal of cations present in Jerusalem artichoke juice.

Hydrogen ion catalyzed hydrolysis is not expensive. This chemical production method is simple, efficient and inexpensive compared to enzymatic methods. Syrup produced in this way is used as a "healthy" sweetener and is especially ideal for elderly people and diabetics. The tuber bulbs obtained after extracting the juice are rich in protein and are used as food.

The cation exchange resin and anion exchange resin are HCI,
It can be quickly regenerated with NaOH and can be reused.

The syrup according to the invention also has the properties of conventional sugars and syrups and may be used as usual.

For example, it can be used as a compounding material for food sweeteners and medicines. Furthermore, it can be used in general industrial applications instead of sugar or syrup.

The use of fructose-containing syrups according to the invention offers many advantages that are not available when using glucose syrups, invert sugar syrups, sita sugar syrups or sucrose syrups of the prior art. For example, corn syrup and sucrose are often used together to create a complex sweetener that combines the functional benefits of corn syrup with the sweetening power of sucrose. The fructose-containing syrup according to the invention is very sweet for boat fishing and can therefore be used as a replacement for the complex sweeteners mentioned above. Single sweeteners such as fructose-containing syrups according to the invention are easy to handle and store for those who use them. This fact has clear economic advantages. Additionally, sucrose, which is used in many products, undergoes conversion during storage, changing the sweetness of the product. In other words, the sweetness changes depending on the amount of sucrose that is converted. This fact is particularly true for acidic products or products that generate acidic substances during storage. It can be said that the above-mentioned change in sweetness does not occur in the case of the fructose-containing syrup according to the present invention.

χ Blood Stamp Example 1° General method for producing fructo syrup containing fructose syrup and fructo-oligosaccharides from Jerusalem artichoke tubers and chicory rhizomes Step 1° Tubers and rhizomes are washed and shredded, and the same weight of water is added and heated. For example, at about 80 to 100°C for about 20 to 30 minutes. For example, the λ-sulfur is collected by squeezing or filtering. (The juice contains about 5-10% inulin, and the high molecular weight inulin precipitates on cooling.) Step 2: The juice is heated while hot (e.g. about 40-70'C), known for example under the trademark Dou+ex88. The solution is passed through a strongly acidic cation exchange resin (H+ type) such as the one shown in Fig.

The pH of the effluent is between about 2.0 and 3.0.

The pH is adjusted to about 2.0 to 2.5 with hydrochloric acid and sulfuric acid.

Step 3. Inulin is heated at a temperature between about 70-100'C for varying times to hydrolyze it to varying degrees. For example, this operation can be performed using two fill-shaped tubes (
For example, outer diameter 41fiI11, inner diameter 2.5mm, length 24
This can be carried out by flowing the liquid at different flow rates through a glass tube having a volume of 32 ml. Suppose the pH of the liquid is adjusted to about 2.5 and the temperature is 100℃.
If the syrup is heated to about 2.5 minutes, the resulting syrup will contain about 20% simple sugars (mostly fructose).
and about 80% fructooligosaccharides, and in a processing time of about 5 minutes, a syrup consisting of 50% monosaccharides and 50% fructooligosaccharides is obtained.

Step 4: The solution after hydrolysis is cooled to room temperature and filtered using, for example, a Whatman glass #&l filter GF/A (Whatman glass #&l filter GF/A).
ss fiber filter GF/A). This filter can be reused after cleaning with dilute alkali and water.

Step 5 decolorization can be carried out with i) powdered activated carbon, or ii) granular activated carbon. i) For 100 parts of the filtrate, 1 part of powdered activated carbon, such as is known under the trademark N0RIT SX 2 is mixed and passed through a press filter. or 11) For example N0RIT ROXo, 8
The filtrate is passed through a column filled with granular activated carbon (previously washed with water to remove fine particles), known under the trademark .

If fine granular activated carbon is contained in the passing liquid,
They are Whatman glass fiber
``It can be removed by passing it through fine filters known under trademarks such as 1lterGF/F, cellulose acetate membranes or cellulose sulfate membranes (0.45μ).

Step 6: The activated carbon-treated liquid is passed through a column of porous weakly basic anion exchange resin (OH type), such as that known under the trademark Dou+ex66. The r+H of the eluate increases, for example, to about 6.5-7.0.

Step 7: The anionic active resin treatment solution is dried by evaporation only or by reverse osmosis followed by evaporation drying, for example, to a solid state of about 40
Concentrate to ~70% syrup.

The analysis results of the four types of syrups obtained by the above inulin hydrolysis are as follows.

The results of spectroscopic analysis of the four syrups shown above are shown in Figure 1-4.
This is shown below.

Example 2゜Example 1. Specific modification process of the general method 2. The strongly acidic cation exchange resin used in the above description is a sulfonic acid-based cation exchange resin known under the trademark Dou+ex88.

Other cation exchange resins that can be used are DOW2X8
, DOW 21. R, DOWEX50 WX4
Amber1iteIR%A+berlite401,
There is one known under the trademark PERMUTIT MP600.

Step 6. The removal of anions in Dowex 6
A porous weakly basic anion exchange resin known under the trademark 6 is used. Other weakly basic anion exchange resins that can be used include those known under the following trademarks.

DUOLITE A-6, DUOLITE A-7
, DUOLITE A 3OB, and DUOLI
TE ESS61 (Diamond Shamro
ck company), I0NACA 300 (Ionac company)
, Amberl 1teIRA 475, IRA-
93 (Amberlite).

Typical resins used in accordance with the present invention are divinylbenzene crosslinked sulfonic polystyrene resins, such as DOWEX 50W, ZEOKARB 22
There is one known under the trademark S.Amberlite252. For example, resins with a low degree of crosslinking such as those crosslinked with about 1% (W/W) divinylbenzene, or resins with a low degree of crosslinking such as those crosslinked with about 1% (W/W)
Resins with a high degree of crosslinking, such as those crosslinked with 2% (W/W) divinylbenzene, have intermediate degrees of crosslinking, such as those crosslinked with about 2-8% (W/W) divinylbenzene. O (less effective than fat). The lentils that can be used generally have grain walls of about 20 to 100 mesh.

Furthermore, the base material of the resin that can be used is, in principle, made of polystyrene and has a relatively low degree of crosslinking. Polystyrene resins with sulfone groups, which have a relatively low degree of crosslinking of 2 to 6%, are also used as ion exchange resins.

Other anion exchange resins can also be used. Examples include m-phenylenediamine, biguanides, guanylurea, substituted guanidines such as methylguanidine, substituted biguanides such as phenylguanide, preferably polyethylene, aldehyde condensation products of polyamines. Formaldehyde condensates are preferably used as condensation products. Other aldehydes include furfural, acrolein, and benzaldehyde. Active resins prepared from guanidine, guanylurea, biguanides, and other compounds that do not form completely insoluble condensates with formaldehyde, to name but a few, include urea, thiourea, ami/triazine M (particularly those that react with formaldehyde). It is desirable to make it insolubilized with a compound that reacts with formaldehyde, such as melamine or guanamine, which creates an insoluble substance. Although it is usually convenient to use salts of bases, evacuated bases can also be used. Suitable salts used in preparing anionically active resins include guanidine carbonate, guanidine sulfate, guanylurea carbonate, and the like.

Activation of the anionically active resin can be carried out in a conventional manner by treatment with a dilute aqueous alkaline solution, such as about 0.1 to 10% sodium hydroxide, sodium carbonate, or the corresponding potassium salt aqueous solution. In particular, hydroxide is effective for regenerating the resin in the present invention.

As the fourth step in the present invention, it is desirable to carry out a decolorization step using activated carbon known under the trademark Norit 5X2. Pond decolorizing agents include bone char, diatomaceous earth, bauxite, and bone char as provided by Canadian Patent No. 1,133,881. Activated carbon/bone char mixtures having an activated carbon composition of 10 to 50% may also be used, but most preferably mixtures contain 10 to 30% activated carbon. The remainder of this composition naturally becomes bone charcoal.

As granular activated carbon such as bone charcoal, 8 x 50 mesh or 8 x 35 mesh is suitable. This passes 95 to 100% with large scales according to the American standard, and O~100% with small scales.
This means that 5% will pass.

[Brief explanation of the drawing]

1 to 4 show diagrams obtained by analyzing four kinds of syrups obtained by the method of Example 1 using high performance liquid chromatography. The equipment used is Shima rLc-5A, and the column used is Shimazu P.
N 82, the detector is a differential refractometer, and the solvent is acetonitrile:water (70:30). Figure 1 Figure 2 F 5.43 26.2G
5.91 7.2F26.88 38.
1 F 16.36 4.6 So
9.3 Attribution Retention time 0
υ Composition ('/,)F 5.45
45.1G 5.95 13.5
F26.92 36.7 F3 9.55 3.3F412.5
2 1.6 F 15.85 0.6 Fig. 4

Claims (1)

[Claims] 1. A series of operations represented by a) to e) below a) Obtaining an aqueous solution containing inulin b) Applying the aqueous solution to a strongly acidic cation exchange resin column at about 40 to 70°C. By passing the liquid through, the pH will be about 2.0 to 3.
c) Hydrolyzing the effluent by heating it to about 70 to 100°C d) Passing the hydrolyzate through a weakly basic anion exchange resin column to adjust the pH. A process for producing a syrup containing fructooligosaccharides by hydrolyzing inulin, comprising the steps of: e) concentrating said effluent to obtain an effluent of about 6.5 to 7.0. 2. The method according to claim 1, wherein the aqueous solution containing inulin is obtained from Jerusalem artichoke tubers or chicory rhizomes. 3. The method of claim 1, wherein the aqueous solution containing inulin contains inulin at a concentration of about 5-10%. 4. The method according to claim 1, wherein the inulin aqueous solution is obtained by heating crushed Jerusalem artichoke tubers or chicory rhizomes in water at about 80 to 100°C for about 20 to 30 minutes. 5. The method according to claim 4, wherein the hot water pulp mixture of the crushed tubers or rhizomes is compressed and filtered to obtain an inulin aqueous solution. 6. The method according to claim 1, wherein the cation exchange resin is a H^+ type of sulfonic acid resin. 7. Adjust the pH of the eluate from the cation exchange resin column to approximately 2.
．． 7. The method according to claim 6, characterized in that the temperature is adjusted to 0 to 2.5. 8. The method according to claim 7, wherein the pH adjustment is carried out using hydrochloric acid or sulfuric acid. 9. The above hydrolysis reaction to give a partially hydrolyzed product is carried out at about 100°C.
8. The method of claim 7, wherein the method is carried out in about 2.5 minutes. 10. The method according to claim 7, wherein the partial hydrolysis reaction is carried out at about 100° C. for about 5.0 minutes. 11. The method according to claim 7, wherein the complete hydrolysis is carried out at about 100° C. for about 15.0 minutes. 12. Claim 1, characterized in that the hydrolyzate treated at about 70°C to 100°C is treated with activated carbon or granular carbon before passing through the weakly basic anion exchange resin column. The method described in section. 13. The method according to claim 1, wherein the anion exchange resin is an OH^- type of porous weakly basic anion exchanger. 14. The method according to claim 1, characterized in that it is carried out to obtain a syrup having a concentration of about 40 to 70% in terms of solids content. 15. The method according to claim 13, characterized in that it is carried out to obtain a syrup having a solid content of about 70%. 16. The method according to claim 1, wherein the concentration is carried out by an evaporation method. 17. The method according to claim 1, wherein the concentration is carried out by a reverse osmosis membrane method. 18. The method according to claim 1, wherein the concentration is carried out by reverse osmosis membrane method followed by evaporation method. 19. The method according to claim 1, wherein the heating is carried out by passing the eluate through a coiled thin tube at about 70 to 100°C.