JPH0346120B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying a sugar solution containing a high concentration of fructose, and in particular a sugar solution in which fructose is chromatographically separated to a high concentration from isomerized sugar obtained by isomerizing glucose using an ion exchange resin or the like. The present invention relates to a method for purifying ion-exchange resins using a combination of specific ion-exchange resins. Fructose is the sweetest sugar among natural sugars, and has been attracting attention as a sweetener in recent years because it is easily soluble in water, making it advantageous for food processing. Conventionally, fructose has been used as liquid sugar by isomerizing glucose, which is made from starch, using enzymes and converting a portion of the glucose into fructose. However, due to the equilibrium relationship of the isomerization rate of fructose, this high fructose sugar usually contains 42% by weight of fructose, 50-55% by weight of glucose, and 3-8% by weight of oligosaccharides, which is compared to sugar. However, the high fructose isomerized sugar is passed through a column packed with a calcium-type strongly acidic cation exchange resin, and fructose and glucose are separated using column chromatography. concentrate to a high concentration of 80% by weight or more. Next, since the sugar solution containing a high concentration of fructose obtained in this way contains impurities such as organic weak acids and pigments, a mixed bed ion exchange column filled with a strong basic anion exchange resin and a strong acid cation exchange resin is used. to remove impurities in the sugar solution,
The sugar solution is purified, but when a normal strongly basic anion exchange resin is used, the disadvantage is that fructose is reverse isomerized to glucose and the fructose content decreases. The rate of reverse isomerization of fructose reaches several percent by weight, and in a concentrated solution with a high concentration of 80 percent by weight or more, a decrease of several percent by weight is extremely disadvantageous industrially. Conventionally, ion exchange resins obtained by copolymerizing styrene and divinylbenzene have been used for these strong basic anion exchange resins and strong acid cation exchange resins, respectively, but the combination of these ion exchange resins Another disadvantage is that the ability to remove impurities from the sugar solution is low. The present invention solves the drawbacks of the method for refining a sugar solution containing fructose, and is particularly effective as a method for refining a sugar solution containing fructose at a high concentration of 80% by weight or more. The purpose is to prevent the concentration of fructose from decreasing by preventing isomerization, improve the degree of purification, and increase the throughput. That is, the present invention uses a strong base anion exchange resin obtained by copolymerizing a sugar solution containing high concentration of fructose with acrylic acid and divinylbenzene, and a weak base obtained by copolymerizing acrylic acid and divinylbenzene. It is characterized by purification by passing the liquid through a mixed bed ion exchange tower using a strongly acidic cation exchange resin obtained by copolymerizing styrene and divinylbenzene. The present invention will be explained in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing the flow of a mixed bed type ion exchange column which is an example of an embodiment of the present invention. resin 3
A strong basic anion exchange resin obtained by copolymerizing acrylic acid and divinylbenzene and a weakly basic anion exchange resin also obtained by copolymerizing acrylic acid and divinylbenzene are filled above the anion exchange resin 2. Mix and fill in appropriate proportions. In addition, a collector 9 is provided at the interface between the strongly acidic cation exchange resin 3 and the anion exchange resin 2, and a recycled waste liquid discharge pipe 8 is connected to the collector 9. A distribution pipe 10 is provided, and a regenerant inflow pipe 7 is connected to the distribution pipe 10. In addition, the raw solution inlet pipe 4 is connected to the upper part of the ion exchange column 1, and the column 1
A processing liquid outflow pipe 5 and a regenerant inflow pipe 6 are connected to the lower part of the pipe. In the present ion exchange tower 1, when refining a sugar solution containing fructose, air is first introduced through the regenerant inflow pipe 6, and the anion exchange resin 2 and the strongly acidic cation exchange resin 3 are thoroughly mixed. Next, the stock solution is allowed to flow downward through the stock solution inflow pipe 4 and passed through a mixed bed of ion exchange resin to remove organic weak acids, pigments, etc., and the processing solution is allowed to flow out from the processing solution outflow pipe 5. When the ion exchange ability of the ion exchange resin decreases, it is regenerated. That is, backwash water is introduced from the regenerant inflow pipe 6 and separated into anion exchange resin 2 in the upper layer and strongly acidic cation exchange resin 3 in the lower layer. The anion exchange resin 2 is easily separated into a weakly basic anion exchange resin in the upper layer and a strongly basic anion exchange resin in the lower layer, but it is not necessary to completely separate both anion exchange resins into two layers. Next, as a regenerating agent, an acid aqueous solution such as hydrochloric acid is caused to flow upward from the regenerating agent inflow pipe 6, and the regenerated waste liquid is discharged from the regenerated waste liquid discharge pipe 8 through the collector 9.
The strongly acidic cation exchange resin 3 located further below is regenerated, and at the same time, water is passed through the regenerant inlet pipe 7 and down through the distribution pipe 10 to press the ion exchange resin layer. The effluent water is discharged from the recycled waste liquid discharge pipe 8 through the collector 9 together with the recycled waste liquid. When the regeneration of the cation exchange resin is completed, an alkaline aqueous solution such as caustic soda as a regenerant is then flowed downward from the distribution pipe 10 through the regenerant inflow pipe 7, and the regenerated waste liquid is discharged through the collector 9. The anion exchange resin 2 above the collector 9 is regenerated by discharging it from the pipe 8, but at the same time, the water is discharged from the regenerating agent inflow pipe 6.
The water flows in with a higher upward flow, and the outflow water is discharged from the recycled waste liquid discharge pipe 8 through the collector 9 together with the recycled waste liquid. When the regeneration of the anion exchange resin is completed, next, washing water flows in from the stock solution inflow pipe 4 and the regenerant inflow pipe 6, and the washing waste water is discharged from the regenerated waste liquid discharge pipe 8 via the collector 9, and both ion exchange resins are Wash. After the regeneration is completed, air is introduced to mix the ion exchange resin as described above, and then the stock solution is passed through. The strongly basic anion exchange resin and the weakly basic anion exchange resin used in the present invention are both copolymerized with acrylic acid and divinylbenzene. Trademark) IRA-
458 (manufactured by Rohm and Haas), and Amberlite IRA- as a weakly basic anion exchange resin.
There are 68. By using a mixed ion exchange resin consisting of a strongly basic anion exchange resin and a weakly basic anion exchange resin that have acrylic acid and divinylbenzene as their base materials, it is possible to use a mixed ion exchange resin that is made of acrylic acid and divinylbenzene. Strongly basic anion exchange resins obtained by copolymerizing styrene and divinylbenzene, such as Amberlite IRA-411 and Diaion (registered trademark) PA-408 (manufactured by Mitsubishi Chemical Corporation)
It is possible to prevent the reverse isomerization reaction of fructose that occurs in other methods, and does not cause a decrease in fructose concentration.
Furthermore, sugar solutions containing high concentrations of fructose obtained through chromatographic separation generally contain almost no inorganic salts as impurities, and contain small amounts of organic weak acids and pigments, but acrylic Anion exchange resin based on acid and divinylbenzene is
It has better adsorption and desorption ability for organic substances than anion exchange resins whose base materials are styrene and divinylbenzene. Therefore, compared to conventional mixed beds, it is possible to improve the purification degree of the treated sugar solution and the throughput. can also be significantly increased. The mixing ratio of both anion exchange resins in the present invention is undesirable because if the ratio of the strongly basic anion exchange resin is large, the degree of purification of the treatment liquid will improve, but the reverse isomerization reaction will occur to some extent and the concentration of fructose will decrease.
On the other hand, if the proportion of the weakly basic anion exchange resin is large, the reverse isomerism of fructose will hardly occur, but the degree of purification of the treatment liquid will decrease, which is undesirable. The resins may be mixed in a volume ratio of 1:1 to 1:4, preferably 1:2. This mixing ratio makes it possible to prevent the reverse isomerization reaction of fructose and to achieve the intended purpose of improving the degree of purification of the treated liquid. Further, in the present invention, the normal temperature of the stock solution is preferably 20 to 35° C., since fructose is more unstable to temperature and more easily decomposed than glucose. Furthermore, if the flow rate of the stock solution is too slow, a reverse isomerization reaction tends to occur to some extent, so SV4 to 8 are preferable for a mixed anion exchange resin of a weakly basic anion exchange resin and a strongly basic anion exchange resin. As explained above, the present invention combines a strongly basic anion exchange resin and a weakly basic anion exchange resin obtained by copolymerizing a sugar solution containing high concentration of fructose with acrylic acid and divinylbenzene, and styrene and divinylbenzene. By passing the solution through a mixed-bed ion exchange tower mixed with a strongly acidic cation exchange resin obtained by copolymerization, it is possible to prevent the reverse isomerization reaction of fructose and improve the yield of fructose. As well as being able to
A highly purified treatment liquid can be obtained and the throughput can be increased. Examples of the present invention will be described below. Examples Amberlite IRA-458 is a strongly basic anion exchange resin obtained by copolymerizing acrylic acid and divinylbenzene, and Amberlite IRA-458 is a weakly basic anion exchange resin obtained by copolymerizing acrylic acid and divinylbenzene. Light IRA-68, and Amberlite, a strongly acidic cation exchange resin obtained by copolymerizing styrene and divinylbenzene.
200C was packed into each column as shown in Table 1. In addition, for comparison with the method of the present invention, Amberlite was used as a strongly basic anion exchange resin obtained by copolymerizing styrene and divinylbenzene.
IRA-411, also Diaion PA-408 and Amberlite 200C as a strong acidic cation exchange resin
were packed into each column as shown in Table 1. Furthermore, a mixed bed using Amberlite IRA-458 alone as an anion exchange resin was also packed into a column as shown in Table 1.

【table】

[Table] Prior to filling, in the method of the present invention, a mixed resin of a strongly basic anion exchange resin and a weakly basic anion exchange resin, and in the conventional method, a strongly basic anion exchange resin was each 4% by weight hydroxylated. 150 ml of sodium aqueous solution was passed at a flow rate of SV4 for regeneration, and the strongly acidic cation exchange resin was passed through 100 ml of 5% by weight aqueous hydrochloric acid solution at a flow rate of SV4.
It was regenerated by passing it through SV5, and the regenerated ion exchange resin was thoroughly mixed. Next, in each of the columns in Table 1, a concentration of 40% by weight, a pH of 3.8, a total of 75 mg/l of anions (as CaCO ₃ ),
A stock solution with a fructose content of 91% by weight was passed through an anion exchange resin at a temperature of 35°C with a downward flow of SV6, and the specific resistance and fructose content of the treated solution in each column were measured. It is shown in FIGS. 2 and 3. In Figure 2, the horizontal axis shows the processing amount and the vertical axis shows the specific resistance. In Figure 3, the horizontal axis shows the processing amount and the vertical axis shows the fructose content. represents the treated solution of column A, B represents column B, C represents column C, D represents column D, E represents column E, and F represents column F. Column F using the conventional method had a significant decrease in specific resistance;
The degree of purification of the treated liquid is poor, and the fructose content decreases at a higher rate than with other columns. Further, in column E, a treatment liquid with a high specific resistance can be obtained and a large amount can be treated, but the rate of decrease in fructose content is large compared to other columns, similar to the above-mentioned column F. Column D has the lowest rate of reverse isomerization of fructose among conventional columns, but has a significant decrease in specific resistance and a small throughput. Columns A, B, and C of the method of the present invention compared to these columns of the conventional method.
In each case, a treatment solution with a high specific resistance was obtained, the amount of treatment was large, and the decrease in fructose content due to reverse isomerization of fructose was extremely small, and a good treatment solution was obtained. Furthermore, in columns A, B, and C of the method of the present invention, the volume ratio of the strongly basic anion exchange resin to the weakly basic anion exchange resin is 1:1 in column A;
The ratio is 2:1 in column B and 1:2 in column C, and the higher the amount of weakly basic anion exchange resin, the higher the fructose content in column B, column A, and column C, but the specific resistance is the opposite. The value increases in the order of column C, column A, and column B, and the degree of purification improves, so from the specific resistance and fructose content,
The best treated solution was obtained in column C.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the flow of a mixed bed type ion exchange column which is an example of an embodiment of the present invention, and FIG.
The figure is a graph showing changes in the specific resistance of the treated solution of each column in the examples of the present invention, where the horizontal axis shows the processing amount (l/l-anion exchange resin), and the vertical axis shows the specific resistance (Ω・cm). Figure 3 is the second
This is a graph showing changes in the fructose content of the treatment solution shown in the figure, in which the horizontal axis represents the processing amount (l/l-anion exchange resin) and the vertical axis represents the fructose content (%). Note that A in the line graphs in Figures 2 and 3 is column A,
B is column B, C is column C, D is column D, E
Columns E and F indicate the respective treated solutions in column F. 1... Mixed bed ion exchange tower, 2... Anion exchange resin, 3... Strongly acidic cation exchange resin, 4...
Raw solution inflow pipe, 5...Treatment liquid outflow pipe, 6...Regenerant inflow pipe, 7...Regenerant inflow pipe, 8...Regenerated waste liquid discharge pipe, 9...Collector, 10...Distribution pipe.

Claims (1)

[Claims] 1. A strongly basic anion exchange resin obtained by copolymerizing a sugar solution containing high concentration of fructose with acrylic acid and divinylbenzene, and a weakly basic anion exchange resin obtained by copolymerizing acrylic acid and divinylbenzene. Purification of a sugar solution containing a high concentration of fructose, characterized by purification by passing the solution through a mixed bed ion exchange tower using a strongly acidic cation exchange resin obtained by copolymerizing styrene and divinylbenzene. Method.