JPH088841B2 - Method for collecting taste components in bean jam wastewater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention performs a purification treatment prior to discharging wastewater discharged from a bean filling factory, and presents valuable materials contained in the wastewater, particularly The present invention relates to a method for recovering a taste component.

(Prior art) Among the bean jams conventionally used for sweet foods such as confectionery, rice cakes, breads and instant foods, for example, as a method for producing ground bean from beans, soil and impurities are removed. Washing process, if necessary boiled in water once or several times, astringent process, and then boiled or boiled in water until it is sufficiently softened and swelled. Is generally done. In this method, the wastewater discharged from each of the above steps has a remarkably high biochemical oxygen demand (BOD) value.
It looks like the table.

In addition, the so-called bean paste manufacturing method, after the main ripening in the above-mentioned bean paste manufacturing method, through a grinding step, a solid-liquid separation step and a primary and secondary exposure step of immersing in water, a dehydration step by a filter-press, etc. Add sugar and knead. The typical example of the amount and quality of wastewater discharged from each process at this time
Shown in the table.

In view of its high BOD value, the above wastewater is discharged after being subjected to conventional aerobic biochemical treatment such as the activated sludge method in view of the need for environmental protection, and raw sludge such as excess sludge produced as a by-product is directly dehydrated. It is currently being disposed of for composting or incineration.

However, the combustion cost of direct dehydrated sludge with high solid content consumes enormous heat energy, and the activated sludge treatment method requires enormous capital investment, heat power and other maintenance costs. , Was the main cause of rising production costs.

In addition, since the petroleum energy crisis was exclaimed, an anaerobic digestion method that produces methane gas that is energy-saving and is expected to be effectively used has been reviewed, but this method requires a long treatment time and requires large equipment. Therefore, there is a problem in that it occupies a large installation space.

The rationalization of wastewater treatment systems, which have many problems as described above, has been a yearning for industry.

On the other hand, the bean jam wastewater is various components extracted from the raw beans in the boiling process consisting of the astringent process and the ripening process,
For example, it contains a large amount of free amino acids, tannins, etc. shown in Table 1, and although it seems that some of them naturally contain valuable components, their recovery and effective utilization are completely neglected. It was subjected to wastewater treatment as it was.

(Problems to be Solved by the Invention) In the process of rationalizing the wastewater treatment system in the bean making process, the present inventors have found that the wastewater contains a large amount of valuable substances, especially taste components of raw beans. Focusing on this point, we succeeded in its recovery and utilization, and by incorporating this recovery method into the improved wastewater treatment process, we were able to achieve a significant rationalization of the wastewater treatment method.

A first object of the present invention is to provide a streamlined treatment system for wastewater discharged from a bean jam factory.

The second object of the present invention is to recover valuable substances, particularly taste components, in the wastewater of bean jam factory.

A third object of the present invention is to provide a bean jam with a rich flavor peculiar to the raw material beans.

(Means for Solving the Problems) The present invention, which is the basis for achieving the above-mentioned object, has the above-mentioned method when a bean bean paste is subjected to a boiling treatment including astringent cutting step and simmering step. A method for recovering a taste component in bean jam wastewater, which comprises subjecting the wastewater discharged from at least one of the astringent cutting process and the simmering process to ultrafiltration to recover the permeated liquid.

The free amino acid in the permeate /
The tannin ratio (hereinafter referred to as A / T ratio) is preferably at least 1.5.

The ultrafiltration is preferably carried out using an ultrafiltration membrane having an amino acid rejection of 40% or less and a tannin rejection of 60% or more.

In a preferred embodiment of the method of the present invention, the permeated liquid is further subjected to a dehydration step to reduce the volume.

Such dehydration step is preferably concentration by a reverse osmosis membrane, more preferably concentration by a reverse osmosis membrane and subsequent drying.

Further, it is particularly preferable to substantially remove suspended solids in the waste water by preliminary filtration prior to the ultrafiltration.

It is effective that the wastewater to which the method of the present invention is applied is cooked wastewater discharged from the main ripening (hereinafter referred to simply as ripening) step.

The most common and important beans for bean jam are azuki beans.

Further, the method of the present invention in which such a taste component recovery method is incorporated into a part of the bean jam wastewater treatment system is the above-mentioned astringent cut at the time of making bean beans by subjecting the beans to a boiling process including an astringent cutting step and a ripening step. The wastewater discharged from at least one of the process and the ripening process is subjected to ultrafiltration to collect the permeated liquid, and the retentate is subjected to a biochemical digestion process. It is a characteristic method for recovering taste components from bean jam wastewater.

The biochemical digestion step comprises an anaerobic digestion step.

The constitution of the method of the present invention will be described in detail below with reference to the accompanying drawings with respect to its aspects.

FIG. 1 shows a flow sheet of the taste component recovery method which is the basis of the present invention. In the figure, PF is a pre-filter, UF is an ultrafiltration membrane, RO is a reverse osmosis membrane, and SD is a spray drying process.

The bean jam waste water referred to in the method of the present invention includes those discharged from the bean jam making process using a variety of beans such as adzuki bean, Hidden bean, peas and quail beans, but in the following description, a typical bean is particularly representative. More about bean jam wastewater.

The wastewater to which the method of the present invention is applied can include both boiling treatment wastewater, that is, the one discharged from the astringent cutting step and the one discharged from the ripening step in Table 1, and the A / T ratio is generally It is in the state of 1 or less, that is, an equivalent amount to a tannin-rich state. It is most desirable to treat only the boiled ripening wastewater from the viewpoint of the recovery efficiency of valuable resources, and if the wastewater for the second time of astringent cutting is mixed with it, the desired valuable materials can be recovered with almost no waste.

The method of the present invention comprises subjecting the above-mentioned wastewater to ultrafiltration (UF) to obtain a permeate containing an excess of free amino acids over tannin, and then repeating the cycle. It is preferable that the A / T ratio in the permeate is at least about 1.5 by such ultrafiltration, and for that purpose, an ultrafiltration membrane having an amino acid rejection rate of 40% or less and a tannin rejection rate of 60% or more is applied. Is good. Ultrafiltration is performed under pressure using an ultrafilter equipped with a commercially available ultrafiltration membrane, and the above rejection rate was experimentally measured according to the characteristics such as the molecular weight cutoff of the ultrafiltration membrane. , Select a filter with appropriate performance. For example, the molecular weight cutoff 6,
It has been experimentally confirmed that a filter membrane of about 000 to 30,000 can be preferably used. Table 3 shows the specifications of typical products among the commercially available ultrafiltration membranes, and the amino acid inhibition rate and tannin inhibition rate in the boiled effluent.

The amino acid-rich ultrafiltration membrane permeate obtained as described above contains abundant taste-enhancing components, so it is returned to the bean making process as it is, or added to the raw material immediately before kneading or kneading,
Alternatively, it may be filled and packaged and shipped as a flavoring.

Further, it is preferable that the permeated liquid is further subjected to dehydration treatment to increase the component concentration, and such dehydration treatment can be carried out by known or conventional distillation, evaporation, etc., but it is possible to save thermal energy and to use low boiling point useful components. From the viewpoint of volatilization prevention, concentration by reverse osmosis membrane (RO) is most desirable. As a reverse osmosis membrane, a salt blocking rate of at least about 70% usually shows an amino acid blocking rate of 90% or more, and it is preferably used for the purpose of concentration.

The reverse osmosis membrane retentate is a concentrated extract of the taste-enhancing component and can be used as it is as a flavoring agent, but by further drying it into a powder form, the commercial value can be significantly increased. For such drying, known means can be appropriately applied, and among them, spray drying (SD) shown in FIG. 1, freeze drying, vacuum drying and the like are preferable.

Prior to the ultrafiltration, it is effective to maintain the efficiency of the ultrafiltration membrane by performing preliminary filtration as shown in the figure, that is, removing contaminants and SS in the wastewater through a prefilter (PF) with an average pore size of about 10 μm. Therefore, it is preferable.

Next, FIG. 2 is a flow sheet showing a concrete example of a wastewater treatment system incorporating the above-mentioned basic method of the present invention.

In the figure, the UF membrane retentate is guided to the anaerobic treatment tank, exposed as required, combined with wastewater, and if necessary, gently stirred and digested under anaerobic conditions at a temperature of about 30 to 60 ° C. To be done. Next, the wastewater is mixed with wastewater of each step such as washing, astringent cutting, bleaching, dehydration and the like, and subjected to a known / common aerobic digestion treatment by an activated sludge method or the like. These anaerobic or aerobic biochemical digestions can be either one depending on the situation, but they are energy-saving and concentrated to a small amount.
Considering the digestion efficiency of the UF retentate, it is economically most advantageous to apply at least anaerobic digestion. In addition, methane gas generated by the decomposition of organic matter during anaerobic digestion can be collected and used as a heat source for the process.

(Working) Various organic components extracted from raw beans with hot water are contained in bean jam wastewater, which has a bad influence on texture and flavor, such as tannin, which has a strong astringent taste. It contains a large amount of the disagreeable component to be exerted and a flavor component mainly composed of free amino acids which gives the flavor and nuisance peculiar to the raw material beans. Tannin, which is the main component of the dislike component, has a high molecular weight of about 600 to 2,000, while the molecular weight of amino acids, which are the taste component, is about an order of magnitude smaller. In the method of the present invention, the wastewater in the boiling treatment stage, which mainly contains the boiled and matured wastewater having an A / T ratio of about 1 or less, is a dislike component such as high molecular weight tannin due to the action of an appropriately selected ultrafiltration membrane. The A / T ratio of the permeated liquid is about 1.5 or more, and the taste components are efficiently collected. The taste component can be significantly reduced in volume by subjecting it to reverse osmosis membrane treatment, collecting the reverse osmosis membrane retentate as a concentrated extract, or further drying and dehydrating.
In addition, since the reverse osmosis membrane has a high salt rejection rate, the permeated liquid is sufficiently cleaned, and it can be recycled and reused in the process. Further, if a pre-filter having an appropriate pore size is provided, it has a function of capturing contaminants, SS, etc., and maintaining good efficiency of the ultrafiltration membrane for a long time.

In the bean jam wastewater treatment system that incorporates the taste component recovery method as described above, the liquid to be treated that has undergone a reduction concentration as an ultrafiltration membrane retentate is efficiently and easily processed in an anaerobic treatment tank with a relatively small volume. Since it is digested to produce methane gas and the BOD value is drastically reduced, it can be discharged as it is, but it can also be combined with other wastewater and subjected to aerobic treatment for easy purification.

(Example) Hereinafter, the method of the present invention will be described in more detail with reference to Examples.

Example 1 Suspended organic solid content 460 mg /, free amino acid content 30
As shown in the process flow sheet of Fig. 1, the boiled and aged wastewater with 0 mg / and tannin content of 390 mg / azuki bean paste manufacturing process is freeze-dried through a pre-filter, an ultrafiltration membrane and a reverse osmosis membrane in sequence. It was made into powder.

The contents and scale of the experimental apparatus for the above steps were as follows.

[Properties of film used]

Prefilter: Average pore size 10 μm UF membrane: Use from those shown in Table 3 RO membrane: SC-L (Toray, cellulose acetate membrane, salt rejection rate 70
%) The freeze-dried powders obtained as described above from the membrane treatment solution were added to fresh bean paste and eaten, and the taste enhancing effect was evaluated by a panel test by 12 panelists. The score was represented by the ratio of those who added the powder to enhance the red bean-likeness.

The results are shown in FIG. As is clear from the figure,
The effect of enhancing the taste of the prefilter permeate (A / T ratio: 0.7 to 1.0) was not observed so much, and the ultrafiltration membrane permeate (A / T ratio> 1.
When 1) was added, the azuki-likeness was evaluated highly, and those with an A / T ratio of 1.5 or more showed a remarkable taste enhancing effect.
On the contrary, the tannin-rich solution obtained from the UF membrane retentate had a negative effect. That is, it is considered that the odorant component mainly composed of tannin is considerably blocked by the ultrafiltration membrane, and the taste enhancing component mainly composed of free amino acid is recovered by the reverse permeable membrane. It was also found that the strength of the taste effect was greatly influenced by the A / T ratio, and the effect increased as the value increased.

Example 2 A anaerobic treatment tank having a capacity of 3 was loaded with porous ceramics as a carrier for immobilizing anaerobic bacteria, and the boiled wastewater and the exposed wastewater were treated respectively. Table 4 shows the results.

The treatment conditions were a high temperature bath temperature of 55 ± 2 ° C. As is clear from the above table, the anaerobic treatment of boiled wastewater can significantly reduce the BOD value in a short time of HRT of 0.6 days by appropriately selecting the conditions. The filtration membrane retentate became even more remarkable, facilitating subsequent aerobic treatment.

(Effects of the Invention) The method of the present invention has the above-mentioned constitution and has an excellent action, and is capable of producing the rich flavor and nourishment contained in the bean jam wastewater that has been conventionally discarded. It is possible to collect and reuse valuable substances such as taste components that are possessed. Especially, since an ultrafiltration membrane is applied for the recovery and a reverse osmosis membrane is used for concentration thereof, it is very inexpensive and has a high yield. And obtain valuables. Further, if the taste component collected as the ultrafiltration membrane permeate is circulated as it is in the bean jam making process and added at the time of sugaring and kneading, it is possible to provide a bean jam product having an excellent flavor and flavor. Then, the extract concentrated by the reverse osmosis membrane and the powdery taste component obtained by further drying it are remarkably reduced in volume and convenient for packaging and handling, and thus become a product with extremely high commercial value at the distribution stage and during use. . Furthermore, the efficiency of the ultrafiltration membrane can be favorably maintained for a long time by providing the prefilter immediately before the ultrafiltration. Since the reverse osmosis membrane permeate can be recycled and reused as reclaimed water in the bean filling process, it also has a water saving effect.

By incorporating the taste component recovery method with such remarkable effects into the bean jam wastewater treatment system, efficient anaerobic treatment of boiled wastewater can be achieved, and downsizing of the anaerobic treatment facility can be achieved. In addition, not only the use of methane gas by-produced by anaerobic treatment, but also the BOD value significantly decreases, so conventional aerobic treatment proceeds extremely easily, enabling aerobic treatment facilities to be downsized and reducing energy consumption by reducing excess sludge. Along with the effects, a thorough rationalization of the wastewater treatment system will be achieved.

In addition to such rationalization of the wastewater treatment system itself, the added value of recovering and reusing valuable resources together brings about great economic benefits.

[Brief description of drawings]

FIG. 1 is a basic process flow sheet of the method of the present invention, FIG. 2 is a process flow sheet of the method of the present invention incorporated into a wastewater treatment system, and FIG. 3 illustrates the effect of the method of the present invention. 5 is a graph showing the results of a panel test for

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koji Mizuno 5-6-3, Shinooka, Komaki City, Aichi Prefecture (56) References JP-A-48-88243 (JP, A) JP-A-61-15662 (JP) , A)

Claims (4)

[Claims] 1. A method of boiling at least one kind of beans selected from the group consisting of adzuki beans, secret beans, pea beans, and quails, which is subjected to a boiling treatment including astringent cutting step and a simmering step, A method for recovering a taste component in bean jam wastewater, which comprises subjecting the wastewater discharged from at least one of the astringent cutting process and the simmering process to ultrafiltration to recover the permeated liquid. 2. The method for recovering a taste component in bean jam wastewater according to claim 1, wherein the free amino acid / tannin ratio (A / T ratio) in the permeate is at least 1.5 by the ultrafiltration. 3. The method for recovering a taste component in bean jam wastewater according to claim 1, wherein the permeated liquid is further dehydrated. 4. A method of boiling at least one kind of beans selected from the group consisting of adzuki beans, secret beans, pea beans, and quails, which is subjected to a boiling treatment comprising a step of astringent cutting and a step of simmering and boiled and ripened. Waste water discharged from at least one of the astringent process and the ripening process is subjected to ultrafiltration to recover the permeated liquid, and the retentate is discarded after the anaerobic digestion process. Method for recovering taste components inside.