JP2000050900A - Production of xylose from corn core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce xylose at a low cost in consideration of the problem that production cost can not help increasing in employing processes of purification concentration and crystallization of saccharified solution when producing xylose by treating corn cores according to conventional methods. SOLUTION: When producing xylose from corn cores, the method of this invention is as follows: (1) crushing corn cores and feeding forcefully them along with charge water into a converter by means of a pump; (2) circulating filtrate discharged from the bottom of the converter through a collector into the top of the converter to decrease the volume of crushed corn cores with hydraulic pressure and to increase a charge of cores in the converter; (3) hydrolyzing the corn cores with acid and pressurized steam; (4) collecting xylose solution, followed by subjecting it to purification, concentration and crystallization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing xylose from corn wick.

[0002]

2. Description of the Related Art In Japan, xylitol was approved as a food additive in April 1997, and its demand has rapidly increased due to its excellent sweetness and anti-caries properties, and the demand for xylose as its raw material has also increased rapidly. I have. Conventionally, xylose has been produced by acid hydrolysis of cottonseed, corn wick, sugarcane juice, birch tree, and the like.

[0003]

However, in the above-mentioned conventional method for producing xylose, when the corn wick is treated by the conventional method, the amount of the raw material which is bulky and charged into the saccharification can is 150 kg / m ^3. The concentration of the saccharified solution obtained after the hydrolysis is a dilute solution of 4.0 to 4.8% by weight, and the production cost is high if it is produced through purification, concentration and crystallization steps. There was a problem that it could not be obtained.

[0004]

In order to solve the above-mentioned problem, the present invention is a first invention corresponding to claim 1 in which corn corn is ground to reduce its specific volume first. This is fed into a saccharification can (acid-resistant pressure vessel) via a pump together with the charged water, and the filtrate discharged from the bottom of the saccharification can through the collector is circulated to the top by a pump, and the crushed core is removed. Reduce its volume by hydraulic pressure,
Provided is a method for producing xylose from a corn core, wherein after increasing the amount of the core charged in the saccharification can, a concentrated xylose solution is obtained by hydrolysis with a conventional acid and pressurized steam to obtain a concentrated xylose solution. As a second invention corresponding to Item 2, a corn core is hydrolyzed with an acid and pressurized steam in a saccharification can to separate a saccharified solution and a residue, and then the saccharified solution is again put into the saccharification can and a new corn core is added. Is added and adjusted to a prescribed pH by replenishing the acid, or without adding acid at all, hydrolyzing with pressurized steam to obtain a concentrated xylose solution Producing xylose from a corn core To provide a way to do so. After decomposing the corn wick with an acid and pressurized steam in a saccharification can to separate the saccharified liquid and the residue, put the saccharified liquid again into the saccharification can and add a new corn wick to resaccharify. By recycling the acid used and doubling the concentration of the resulting saccharified solution, the amount of acid used per raw material and the cost of deacidifying this acid are halved, and the cost of evaporating and concentrating the subsequent process is increased. Can be reduced to width. Since the raw corn core contains impurities soluble in water such as organic acids, salts and starch granules, it is generally practiced to wash it with heated water beforehand. Although it is impossible to wash only the surface of the core and elute the internal impurities, the internal impurities can be efficiently eluted by crushing the core. Since this ground core contains a large amount of water, impurities can be efficiently removed by dehydrating the core with a compression dehydrator.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a method for producing xylose from a corn core according to the present invention will be described in detail in comparison with a conventional method. Embodiment 1: In the conventional method, the capacity 20
charged with corn core 3T of Daikatamari to saccharification cans of m ^3,
About 200 kg of concentrated sulfuric acid was added to adjust the pH to 1.0,
Hydrolysis is performed for about 3 hours with pressurized steam of 1.8 kg / cm ² to obtain a saccharified solution containing a xylose content of 80% or more. The concentration of the xylose is 4.0 to 4.8.
It is a dilute solution by weight. According to the method of the present invention, the weight of corn corn per volume m ³ can be increased from 150 kg / m ³ to 190 kg / m ³ or more by first pulverizing with a pulverizer. Although the corn wick was resilient and could not be easily crushed, it could be efficiently crushed using a hammer mill with a screen hole diameter of 6 to 10 mm. Further, the crushed wick is pumped into the saccharification can together with the charging water by a pump, and the filtrate discharged from the bottom of the saccharification can through the collector is circulated to the top, whereby the wick is compressed downward by the hydraulic pressure to reduce its volume. The core weight per volume could be reduced to 270 Kg / m ³ . This is because the saccharification can was saccharified by charging 1.8 times as much raw material as in the case where the core of the conventional method was not crushed, so that the capacity increased in the same facility and the amount of sulfuric acid used per raw material was 1.8.
Since the xylose concentration of the resulting saccharified solution is reduced by a factor of 1.8, the cost of the deoxidation treatment in the subsequent steps and the cost of evaporation and concentration can be greatly reduced.

Embodiment 2 Corn wick 3T is charged into a saccharification can having a capacity of 20 m ³ by a conventional method, and sulfuric acid 200 K
g to pH 1.10, and pressurized steam 1.8 kg /
After hydrolysis for 3 hours in cm ^2, the saccharified solution and the residue (solid content) were separated to obtain 13 m ³ of the saccharified solution. 6 m ³ of warm water was added to the residue to wash and extract the sulfuric acid and saccharides remaining in the residue. The saccharified solution and the washed and extracted water were put again in a saccharification can, and 3T of a new corn core was added to perform the second saccharification. Carried out.
Since the pH of the saccharified solution was 1.23, hydrolysis was performed for 2 hours with 1.8 kg / cm ^{2 of} pressurized steam without adding sulfuric acid. Table 1 shows the results of liquid chromatographic analysis of the sugar components of the initial saccharified solution and the saccharified solution for resaccharification.

[0007]

【table 1】 As a result, despite the fact that the amount of xylose is reduced by the decomposition and polycondensation reaction during acid saccharification, the same amount of sulfuric acid can produce a saccharified solution having a xylose content almost twice as much as that of sulfuric acid. .

Embodiment 3: The raw material corn core contains soluble organic acids and salts in addition to pentose, cellulose and lignin as main components. In particular, a large amount is contained in raw material cores stored for long periods in the open air. Since these remain in the saccharified solution after saccharification, they are harmful to the purification of the saccharified solution,
It is preferable to remove it in advance. Before the wick is charged into the saccharification can, a process of adding washing water and washing is performed in advance.Washing the lumps in a large lump removes impurities inside the wick simply by washing the surface of the wick. It is impossible to extract and remove.

[0009]

The method for producing xylose from a corn core according to the present invention has the following effects since it is configured as described above. In the case of the present invention, since the wick is ground, it is effective to add washing water to the wick to elute soluble impurities. In this case, the moisture content of the crushed core remains 95% or more. Therefore, in order to effectively extract and remove the impurities, the effect of the impurity removing treatment must be achieved by dehydrating the content to 70% or less by dehydration using a compression dehydrator. I can't give up. 15 for crushed wick
The organic acid in the washing water when the water content of the core is dehydrated to 70% by a pressing dehydrator (V-press: a pressing dehydrator pressed between two conical disks) after adding double weight water is chromatographed. Table 2 shows an example of the results of the analysis.

[0010]

[Table 2] Organic acid in the core is 1090ppm x 15 = 16350ppm
Since it was included, 85% of the organic acid was removed from the crushed core dehydrated to 70% moisture by the compression dehydrator.

Claims (5)

[Claims] A corn core is crushed and pumped into a saccharification can together with charging water by a pump, and a filtrate discharged from a bottom of the saccharification can through a collector is circulated to a top, and the crushed corn is subjected to hydraulic pressure. By reducing the volume by increasing the amount of the core to be charged in the saccharification can, xylose is manufactured from a xylose solution obtained by hydrolysis with an acid and pressurized steam. Then, a method for producing xylose from corn core. 2. A corn core is hydrolyzed with an acid and pressurized steam in a saccharification can to separate a saccharified liquid and a residue. The saccharified liquid is again put into the saccharification can and a new corn core is added. It is characterized in that a concentrated xylose solution is obtained by hydrolyzing with pressurized steam without replenishing and adjusting the pH to a predetermined value or without replenishing any acid, and xylose is produced from corn core. Method. 3. The method according to claim 1, wherein heated rinsing water is added to the crushed corn core, and pretreatment for dehydration with a compression dehydrator is performed. 4. The method according to claim 3, wherein a V-press (a press dehydrator for pressing a raw material between two conical disks) is used as the press dehydrator. 5. The method according to claim 1, wherein sulfuric acid is used as the acid used for acid-hydrolyzing the corn core in the saccharification can.