KR100450563B1 - Process for producing xylooligosaccharides - Google Patents

Abstract

The present invention relates to a method for producing purified xyloligosaccharides from xylan-containing vegetable raw materials, (a) swelling by swelling by immersing the xylan-containing vegetable raw materials in water, and (b) water to the explosives. Slurry was added to solidify and solid-liquid separation was carried out using a solid-liquid separator to obtain crude sugar. (C) Centrifugation of the crude sugar was carried out, and the supernatant was filtered through a microfiltration membrane. By using the method of the present invention comprising the step of obtaining a concentrated sugar solution and high content of xylose disaccharides and a high content of xylose oligosaccharides can be obtained.

Description

Production method of xyloligosaccharides {PROCESS FOR PRODUCING XYLOOLIGOSACCHARIDES}

The present invention relates to a method for producing xylooligosaccharides from a vegetable source containing xylan.

Xyloligosaccharides are a mixture of two to several combinations of xylose and xylose and are a syrup or powdery substance with a mild sweetness and are naturally contained in bamboo shoots, fruits, vegetables, milk and honey. Xyloligosaccharide is a functional food that improves intestinal function by selectively propagating useful intestinal microorganisms such as Bifidus and Lactobacillus, and it is known that its effect is superior to other oligosaccharides. In addition, it has been reported to have improved lipid metabolism, liver protection and detoxification, and can be used as a low-calorie sweetener and food material because it is difficult to be absorbed by the human body. In addition to food, xyloligosaccharides can be very useful in various fields including medicine, feed, and agriculture. In particular, xyloligosaccharides used in food are known to be most effective for the growth of enteric microorganisms. It is most preferable that the degree of polymerization ranges from 2-3.

In addition, since the reduced xyloligosaccharides hydrogenated are increased in heat resistance and alkali resistance, they can be used as non-coloring food materials and chemical raw materials.

Xyloligosaccharides are produced from lignocellulosic materials (LCMs) on an industrial scale, and common raw materials include wood, corncobs, rice straw, sugar cane pods, grain husks, bran, and the like.

Three methods can be used to produce xylooligosaccharides from the LCM.

The first method involves the direct enzymatic treatment of native xylan-containing LCM, which is of limited applicability. For example, xyloligosaccharides have been produced by enzymatic methods from membranes of citrus pulp (Japanese Patent No. 8103287),

The second method involves treating the appropriate LCM with chemical methods to obtain xylan, which is then hydrolyzed with enzymes to produce xylooligosaccharides. For example, LCM can be treated with an alkaline solution such as NaOH, KOH, Ca (OH) ₂ , ammonia or mixtures thereof to obtain xylan, precipitated with organic compounds (e.g. acids, alcohols or ketones), followed by separation. Hydrolysis with xylanase can yield xylooligosaccharides. This method is not suitable as an industrial production method in that only xylan sufficiently purified from LCM can be used as a substrate of xylanase.

The third method is to obtain xylooligosaccharide in one step from the LCM by hydrolyzing the xylan-containing LCM with steam or water (hot water).

Extraction by steam or hot water is most suitable for the preparation of xylooligosaccharides, since xyloligosaccharides in aqueous solution can be obtained if appropriate extraction conditions are selected. A steam or hot water extraction method is described in detail in Japanese Patent Laid-Open No. 53-44640. Steam or hot water extraction methods include (1) adding water and raw materials to a sealed container and heating them, and (2) adding raw materials to a closed container and heating them to a temperature of 200 ° C. or higher under saturated steam, and then rapidly discharging them into the air. Methods of extraction after treatment are known. However, these methods have a disadvantage of low recovery oligosaccharide content and higher xyloligosaccharides and xylan contents than 5 saccharides than xyloligosaccharides of less than 4 saccharides, and strong coloring of the obtained sugar and xylose crystals.

Therefore, research has been conducted on obtaining a colorless and transparent xyloligosaccharide syrup from an aqueous solution of xylan extracted from steam or hot water, and Japanese Patent Laid-Open No. 61-285999 discloses a cellulase in a wood-vapor-extracted extract. A method of producing a colorless transparent xylooligosaccharide syrup after the low molecular weight by addition of an enzyme such as ultrafiltration, activated carbon adsorption, ion exchange resin treatment, and concentration is carried out sequentially.

According to this method, the steam decay treatment was not suitable for obtaining xylo-oligosaccharides from corncobs, cottonseed shells, etc., and wood was used. Among the decayed extracts of wood, at least 5 sugars and xylan contents were very high. Low content was essential for further enzymatic treatment. In addition, the explosives treated extracts were immediately enzymatically applied to the ion exchange resin after ultrafiltration.In the general method of passing through the ultrafiltration and ion exchange resin after the enzyme treatment, the filtration rate is very slow and a large-capacity ultrafiltration device is required. The overall efficiency is also lowered.

Therefore, there is a need for an improved method for producing and purifying xylo-oligosaccharides more simply and efficiently from natural materials such as corncobs, cotton kernels, etc. using steam aeration treatment.

It is an object of the present invention to provide a method for producing xylooligosaccharides simply and efficiently from vegetable raw materials.

1 is a schematic diagram of a process for producing xylooligosaccharides from xylan-containing vegetable raw materials in Examples and Comparative Examples of the present application,

Figure 2 is a graph comparing the flux during ultrafiltration in the Examples and Comparative Examples of the present application.

According to the above object, in the present invention, a method for producing xylooligosaccharides from xylan-containing vegetable raw materials, (a) swelling by swelling the xylan-containing vegetable raw materials in water and swelling, (b) adding water to the crushed material After slurrying, the crude liquid is separated by a solid-liquid separator to obtain crude sugar, (c) the crude sugar is centrifuged, the supernatant is filtered through a microfiltration membrane, and (d) the filtrate is passed through an ion exchange resin to decolorize the sugar solution. It provides a method comprising the step of obtaining and concentrating.

As the xylan-containing vegetable raw material that can be used in the method of the present invention, corn cobs, cotton shell shell, rice straw, sugar cane pods, grain husks, bran, wood, etc. may be used, and corn cobs are preferably used.

First, in step (a), the raw material is sufficiently immersed in water and swelled. Corn cobs, for example, 4 to 10 times the amount of water is added and left for 0.5 to 24 hours to swell so that the water content is 60 to 80%. In order to explode the swollen raw material, the raw material is placed in an aerator and then held at 160 to 220 ° C., preferably at 180 to 200 ° C. for 3 to 30 minutes, preferably 5 to 20 minutes, and then a receiver tank at atmospheric pressure. Release rapidly. The air pressure in the aerator is then maintained in the range of about 6 to 23 bar, preferably about 10 to 16 bar.

When the temperature is higher than the set temperature during the explosion or the holding time is longer than the set time, the content of xylose monosaccharide increases. On the contrary, when the temperature is low or the time is shortened, the content of xylose disaccharides and trisaccharides decreases. Since the decolorization load increases in the decolorization process, there is a disadvantage that the decolorization treatment also decreases.

In step (b), 0.5 to 2 times of water is added to the explosives obtained in step (a), stirred at 20 to 80 ° C. for 0.5 to 4 hours, slurryed, and the crude sugar solution is separated into solids using a solid-liquid separator. To obtain. In this case, a filter press, a decanter, or the like may be used as the solid-liquid separator.

In step (c), the crude sugar obtained in step (b) is centrifuged to obtain a supernatant, and the sugar solution is obtained by filtration using a microfiltration membrane having a pore size of 0.1 to 5 탆, preferably 0.2 to 1.2 탆.

In step (d), the sugar solution obtained in step (c) is decolorized by treatment with an ion exchange resin and then concentrated. In this step, as the ion exchange resin, a conventional cation exchange resin or anion exchange resin can be used, and it is preferable to use a cation exchange resin and an anion exchange resin sequentially in terms of yield. However, the desired decoloring effect can be obtained even by changing the order or using only one type of ion exchange resin. As the cation exchange resin, a styrene strong acid cation exchange resin having a sulfone group bonded to the resin, for example, DIAION SK1B, PK216, PK228, SPC160H (Samyang Corporation), Amberlite IR120, IR252, IR200 ( Rohm & Haas Co.), S100, SP120, SP114 (Bayer); Methacrylic or acrylic weakly acidic cation exchange resins in which a carboxyl group is bonded to a resin, for example, Dion WK10, WK11, WK40 (Samyang Corporation), Amberlite IRC50, IRC86 (Rohm & Haas Corporation), CNP80 (Bayer Corporation), etc. It is preferable to use a strong acid cation exchange resin. As the anion exchange resin, a styrene strong base anion exchange resin having a trimethylammonium group bonded to the resin, for example, Dion SA11A, PA306, PA308, PA312, PA408, PA412 (Samyang Corporation), IRA401S, IRA404, IRA900 (Rohm & Haas) G), M500Z, MP500A, MP600 (Bayer); Weakly basic anion exchange resins having tertiary amine groups bonded to the resin, for example, diion WA20, WA21 (Samyang), MP62 (Bayer); Styrene-based weakly basic anion exchange resins in which a trimethylammonium group is bonded to the resin, for example, WA30 (Samyang), IRA93SP (Rom &Haas); MP64 (Bayer Corporation) and the like can be used, and it is particularly preferable to use a weakly basic anion exchange resin.

The xyloligosaccharide obtained by concentrating the sugar solution passed through the ion exchange resin under reduced pressure has a high content of xylose disaccharides (X2) and trisaccharides (X3), which have excellent intestinal microbial growth effects even without treatment with xylanase. It is about 25%.

On the other hand, by further performing the xylan decomposing enzyme treatment and ultrafiltration process after the ion exchange resin treatment it is possible to obtain a high quality xylo oligosaccharide solution with increased content of X2 and X3.

Specifically, xylanases, such as xylanase, hemicellulase, and cellulase, in the amount of 1 to 20 U / ml in the decolorized sugar solution obtained by the ion exchange resin treatment. Xylan contained in the decoloring sugar solution is further decomposed into xyloligosaccharide by adding and reacting at 20 to 70 ° C. for 1 to 10 hours. In order to remove the enzyme contained in the sugar solution, the enzyme reaction solution obtained above was filtered with an ultrafiltration membrane having a molecular weight cut-off value of 3 to 30 kDa and concentrated to obtain the desired xyloligosaccharide. have. The xyloligosaccharide obtained by introducing this additional process has a much better product properties because the total content of xylose disaccharides (X2) and trisaccharides (X3) amounts to about 40-50%.

In addition, when the enzyme reaction and ultrafiltration process are carried out after the ion exchange resin treatment as described above, the content of X2 + X3 contained in the finally obtained xyloligosaccharide compared with the case where the enzyme reaction or ultrafiltration process is performed before the ion exchange resin treatment is performed. Can be increased. In addition, since the filtration rate during ultrafiltration can be increased up to about 25 times, the same throughput can be obtained even with a smaller capacity ultrafiltration facility, which is very effective.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these Examples are only for illustrating the present invention, the present invention is not limited to these.

Example 1

80 kg of water was added to 15 kg of Corncob chips and allowed to stand to allow sufficient water absorption. After 15 hours the remaining water was discarded to obtain a swollen corncob with a water content of 76%.

55 kg of swollen corncobs were introduced into the aerator and hot steam was introduced therein to maintain a temperature of 190 ° C. for 13 minutes, and then rapidly discharged into an atmospheric receiver tank with a vent.

The swelling and the swelling were repeated four times. The crushed product was collected, and 210 L of water was added thereto, followed by stirring at 50 ° C for 4 hours.

The resulting extraction slurry was filtered through a filter press (manufactured by Yeongdong Tech) and solid-liquid separated into 276 kg of 5.0 Brix filtrate and 83 kg of cake having a water content of 67%.

The suspension was allowed to settle by centrifuging 276 kg of the filtrate at a throughput of 4.5 L / min at 13,200 X g to give 270 kg of a sugar solution of 5.0 Brix, A420 = 3.98.

30 L of the centrifuged sugar solution was taken and filtered using TMP (Trans Membrane Pressure) 8.5 psig using a 0.3 µm microfiltration membrane (Korea Pole Co., Ltd.) to obtain 29 L of a sugar solution of 4.7 Brix, A420 = 3.325, pH 3.45.

80 ml of strongly acidic cation exchange resin SPC160H (Samyang) and 800 ml of weakly basic anion exchange resin WA30 (Samyang) were filled in a column of 52 mm in diameter and 490 mm in height, and 1400 ml of the obtained sugar solution was added to the WA30 column in the SPC160H column. The eluate was recovered from the start of 0.6 Bx until A420 became 0.015 while flowing at a flow rate of 800 ml / h. The recovered bleached sugar solution was 2.6 Brix, A420 = 0.008, pH 5.26, and the amount was 910 ml.

900 ml of ion-exchange decolorized sugar solution was concentrated by evaporation under reduced pressure of 60 mmHg at a temperature of 60 ° C. to obtain 32 g of concentrated sugar solution of 70.5 Brix, A420 = 0.226.

The overall process of this example is illustrated in FIG. 1.

Example 2

After swelling the corncob, the same procedure as in Example 1 was carried out to microfiltration to obtain 29 L of a sugar solution of 4.7 Brix, A420 = 3.325, and pH 3.45.

1400 ml of the obtained sugar solution was subjected to decolorization treatment with ion exchange resin in the same manner as in Example 1 to obtain 910 ml of decolorized sugar solution having 2.6 Brix, A420 = 0.008 and pH 5.31.

Xylanase was added to 900 ml of ion-exchange bleached sugar solution at a concentration of 10 U / ml and stirred at 50 ° C. for 4 hours.

900 ml of the enzyme reaction solution was filtered using one ultrafiltration membrane (Amicon) cartridge having a cut-off value of 10 kDa to obtain 800 ml of a filtered sugar solution having 2.2 Brix, A420 = 0.005, and pH 3.72.

800 ml of the filtered sugar solution was evaporated under reduced pressure of 60 mmHg at a temperature of 60 ° C. to obtain 24 g of a concentrated sugar solution of 70.7 Brix, A420 = 0.25.

The overall process of this example is illustrated in FIG. 1.

Comparative example

After swollen corncob, the same procedure as in Example 1 was carried out to fine filtration to obtain 29 L of a sugar solution of 4.7 Brix, A420 = 3.325, and pH 3.45.

Xylase was added to 1800 ml of the sugar solution at a concentration of 10 U / ml, and the mixture was stirred at 50 ° C for 4 hours.

1800 ml of the enzyme reaction solution was filtered using two ultrafiltration membrane cartridges (Amicon) having a cut-off value of 10 kDa, thereby obtaining 1400 ml of a filtrate of 3.9 Brix, A420 = 2.195, and a pH of 3.46.

40 ml of strongly acidic cation exchange resin SPC160H (Samyang) and 400 ml of weakly basic anion exchange resin WA30 (Samyang) were filled in a column 52 mm in diameter and 490 mm in height, and 1200 ml of the filtrate was obtained from the WA30 column of the SPC160H column. The eluate was recovered from the starting point of 0.6 Bx until A420 became 0.012 while flowing at a flow rate of 400 ml / h in this order. The recovered bleached sugar solution was 2.4 Brix, A420 = 0.006, pH 5.95, and the amount was 790 ml.

780 ml of ion-exchange decolorized sugar solution was evaporated under reduced pressure of 60 mmHg at a temperature of 60 ° C. to obtain 25 g of concentrated sugar solution of 70.5 Brix, A420 = 0.226.

The overall process of this comparative example is shown in FIG.

Test Example 1: Change in liquid sugar composition during the process

HPLC was carried out under the following conditions to analyze the composition of xyloligosaccharides in the sugar solution obtained in each step of Examples 1, 2 and Comparative Examples:

HPLC system: Knauer

Column: Sugar-PAK I (Waters, USA)

Mobile phase: 0.1 mM Ca-EDTA aqueous solution

Flow rate: 0.3 ml / min

Column temperature: 80 ℃

Detector: RI detector.

X5 or more X4 X3 X2 X1 G A X2 or above X2 + X3 common Centrifuge 50.1 7.0 9.2 10.5 15.1 1.6 4.6 76.8 19.7 Precision Filtrate 50.2 7.8 9.0 10.2 15.4 1.5 4.8 77.2 19.2 Example 1 Ion exchange solution 34.9 10.7 11.1 13.8 21.1 1.9 6.4 70.5 24.9 concentrate 34.7 10.2 11.4 13.5 21.7 1.9 6.5 69.8 24.9 Example 2 Ion exchange solution 33.7 10.4 11.9 13.4 21.6 2.3 6.7 69.4 25.3 Enzyme Treatment Solution 16.5 12.0 15.3 25.5 22.1 2.4 6.3 69.3 40.8 Ultrafiltration Amount 15.7 11.7 16.4 25.7 22.0 2.2 6.3 69.5 42.1 concentrate 14.9 11.0 16.3 25.7 23.0 2.6 6.5 67.9 42.0 Comparative example Enzyme Treatment Solution 42.0 8.4 12.6 13.4 15.7 1.7 4.6 76.4 26.0 Ultrafiltration Amount 34.7 8.9 12.9 16.9 18.4 1.9 5.5 73.4 29.8 Ion exchange solution 14.6 11.3 17.3 22.4 24.6 2.3 7.4 65.6 39.7 concentrate 13.9 11.8 17.3 22.2 24.6 2.6 7.6 65.2 39.5 X1-X5: Xylose 1-5 saccharides G: Glucose A: Arabinose

As can be seen in Table 1, the decolorized sugar solution obtained by the ion exchange resin treatment in Example 1 already contains about 25% of X2 + X3 even if the content of X2 + X3 is not increased by the enzyme treatment. In addition, the xyloligosaccharide solution obtained in Example 2 was increased by 15.5% compared to the sugar solution obtained in the previous step by X2 + X3 by the enzymatic reaction, whereas in the comparative example, X2 + X3 of the sugar solution obtained by the enzymatic reaction was compared to the previous step. Only 6.8% increase. Therefore, it can be seen that the effect of increasing the content of X2 and X3 by the enzymatic reaction is increased after the decolorization step by the ion exchange resin.

Comparing the sugar composition of the final concentrate in Example 2 and Comparative Example, the composition of X2 + X3 was 42.0% in Example 2, 39.5% in Comparative Example was relatively high in the composition of Example 2 X2 + X3. Therefore, in the process of purifying the microfiltered sugar solution, decolorization, enzymatic treatment and ultrafiltration sequentially by ion exchange as in the present invention are most advantageous for obtaining high quality xylo-oligosaccharide having a high composition of X2 + X3. Able to know.

On the other hand, the sugar recovery yield and the required time of the sugar solution obtained in each step of Examples 1, 2 and Comparative Examples are shown in Table 2 below.

Brix A420 Yield rate (%) Duration (hr) common Centrifugation 5.0 3.980 100 Precision filtration 4.7 3.325 90.87 Example 1 Ion exchange 2.6 0.008 50.27 5.8 concentration 70.5 0.226 47.76 Example 2 Ion exchange 2.6 0.008 50.27 10.5 Enzyme treatment 2.6 0.054 50.27 Ultrafiltration 2.2 0.005 37.81 concentration 70.7 0.255 35.92 Comparative example Enzyme treatment 4.7 3.505 90.87 21.7 Ultrafiltration 3.9 2.195 58.64 Ion exchange 2.4 0.006 36.06 concentration 70.5 0.226 33.93 Sugar recovery rate: Sugar recovery rate compared to the centrifuged sugar solution

As can be seen in Table 2, Example 1 has the highest sugar yield and the shortest time required, and thus it can be seen that it is suitable for a xylo-oligosaccharide production process containing about 25% of xylose disaccharides and trisaccharides. Comparing Example 2 with Comparative Example, it can be seen that Example 2 shows a higher value with a slight difference in the final yield, and at the same time, the required time is relatively small. Therefore, it is preferable to use Example 2 as a high quality xylo-oligosaccharide liquid production process.

Test Example 2: Comparison of Flux During Ultrafiltration

In order to calculate the flux versus concentration ratio in Example 2, the filtration membrane unit area was measured by measuring the flow rate of the filtrate passing through the ultrafiltration membrane at the time of 1.4 times concentration, 2 times concentration, and 4.5 times concentration after 5 minutes of filtration. And the flow rate per unit time.

In the comparative example, 5 minutes after the start of filtration, the values at 1.1 times concentration time, 1.2 times concentration time, 1.5 times concentration time and 2.8 times concentration time were measured and converted.

As a result, as can be seen in Figure 2, the initial flux of Example 2 is 717 ml / m ² / min, the initial flux of the comparative example is 83 ml / m ² / min with a difference of about 9 times the filtration rate Tea was gradually enlarged as it was concentrated, showing a difference of 25 times in filtration rate.

Therefore, in order to obtain the same throughput, it can be seen that the process of the comparative example requires a much larger capacity ultrafiltration plant. It can be seen.

By using the method of the present invention, it is possible to efficiently obtain high-quality xyloligosaccharides having a high content of xylose disaccharides and trisaccharides from xylan-containing vegetable raw materials.

Claims (8)

(a) dipping the xylan-containing vegetable raw material in water and swelling, followed by explosive treatment; (b) slurrying by adding water to the explosives obtained in (a) and solid-liquid separation with a solid-liquid separator to obtain a crude sugar solution, (c) after centrifuging the crude sugar obtained in (b), the supernatant was filtered through a microfiltration membrane, (d) passing the filtrate obtained in (c) to an ion exchange resin to obtain a decolorized sugar solution and then concentrating. A method for producing xylooligosaccharides from xylan-containing vegetable raw materials. The method of claim 1, And wherein the xylan-containing vegetable raw material is selected from the group consisting of corncobs, cotton kernels, rice straw, sugar cane pods, grain husks, bran and wood. The method of claim 1, In step (a), the explosion treatment is carried out at 160 to 220 ° C for 3 to 30 minutes. The method of claim 1, Characterized in that in step (c) a microfiltration membrane having a pore size of 0.1 to 5 μm is used. The method of claim 1, And after the ion exchange resin treatment of step (d), xylanase treatment and ultrafiltration processes. The method of claim 5, wherein Xylase, hemicellulose or cellulose. The method of claim 5, wherein The xylan degrading enzyme treatment is carried out by adding the xylan degrading enzyme to the sugar solution obtained after the ion exchange resin treatment in an amount of 1 to 20 U / ml and reacting at 20 to 70 ° C. for 1 to 10 hours. The method of claim 5, wherein The ultrafiltration membrane used in ultrafiltration has a molecular weight cut-off value of 3 to 30 kDa.