JP5044901B2 - Method for producing water-soluble polysaccharide - Google Patents

Description

The present invention relates to a method for producing water-soluble polysaccharides useful in the food industry from plant materials. Specifically, it relates to a method for extracting and producing water-soluble polysaccharides by heating a suspension of plant material by introducing high-temperature and high-pressure steam, and further functions in the food field such as the stabilization function of acidic proteins. The present invention relates to a method for efficiently extracting a useful water-soluble polysaccharide having excellent properties.

  Plant-derived water-soluble polysaccharides are widely used as functional agents in the food industry, including those used as dietary fiber. Fruits, cereals, potatoes, beans, oilseed plants and the like are known as plant fiber raw materials for these polysaccharides.

  As a technique for extracting and producing a water-soluble polysaccharide from a plant raw material, a method of adding water to the raw material and heating it in an acidic, neutral, or alkaline manner has been known. For example, there is a method of extracting water-soluble polysaccharides at a pH of about 130 ° C. or less at a pH near the isoelectric point of protein (Patent Document 1), but this method usually requires a long time of 60 minutes or more. In addition, an efficient extraction method is desired in a shorter time.

  Also known is a method for obtaining water-soluble hemicellulose by heating the cereal and bean hulls from 130 ° C. to 160 ° C. In this method, the temperature is raised to increase the yield. If it tries to do so, there is a problem because coloring and low molecular weight progress.

  Moreover, although the method (patent document 3) which extracts a water-soluble polysaccharide at 80 degreeC or more using hexametaphosphoric acid as an extractant is disclosed, using such an extractant itself to foodstuffs is disclosed. There is a problem in use.

  Furthermore, a method of performing extraction in a short time by contacting with high temperature / high pressure water (Patent Documents 4 and 5) is also known. However, because the pressure is very high, the equipment becomes large and the desired quality and In order to obtain a polysaccharide having a function, there is a problem that it is difficult to control extraction conditions.

Japanese Patent Laid-Open No. 03-236759 Japanese Patent No. 2544634 Japanese Patent No. 3213648 JP 2002-127724 A JP 2002-105101 A

  The present invention is a method for producing a high-quality, water-soluble polysaccharide having a useful function in the food industry from a plant fiber raw material by a simple method, efficiently in a short time, and without causing excessive decomposition reaction. Is to provide. A main example of a function useful in the food industry is a function for stabilizing acidic protein foods.

  As a result of intensive studies in view of the above points, the present inventors have made it easy to extract water-soluble polysaccharides by blowing high-temperature and high-pressure steam into a suspension containing plant fiber raw material and heating it. Knowledge has been obtained and the present invention has been completed. This is thought to be due to the fact that the cell wall of the plant fiber raw material is efficiently destroyed and the extraction of water-soluble polysaccharides is facilitated by the physical share at the time of introduction of steam. Further, by performing heating by introducing water vapor a plurality of times, and performing an operation of instantaneously reducing the pressure of the raw material suspension and cooling after the heating, a blasting effect can be obtained, and more efficient water-soluble polysaccharides can be obtained. The knowledge that extraction can be performed was acquired, and the invention was able to be developed. In general, a method of releasing the pressure up to atmospheric pressure is used for the decompression operation.

  That is, the present invention is a method for producing a water-soluble polysaccharide, comprising a step of introducing high-temperature and high-pressure steam into a suspension of plant fiber raw material and heating it. The present invention also relates to a method for producing a water-soluble polysaccharide in which high-temperature and high-pressure steam is introduced several times, and the present invention is also a method for producing a water-soluble polysaccharide using soybean as a plant fiber raw material.

The present invention further relates to the method for producing a water-soluble polysaccharide as described above, wherein the plant fiber raw material has a pH of 3 to 7 and a heating temperature of 140 ° C. or higher. The water vapor pressure to be introduced is 6 kg / cm 2. This is the method for producing a water-soluble polysaccharide as described above.

Furthermore, the present invention is a method for producing a water-soluble polysaccharide in which a total heating time of a plurality of heatings is performed within 30 minutes when the plant fiber raw material is heated a plurality of times. It is a method for producing a water-soluble polysaccharide characterized by passing through a step of depressurizing the raw material suspension instantaneously after heating.

  According to the present invention, it is possible to efficiently produce water-soluble soybean hemicellulose having high functions such as stability of milk protein under acidic conditions in a short time by a simple method.

  The present invention is described in detail below.

  In the present invention, plant materials used as raw materials include apples and citrus fruit peels, cereals and strawberries, beans, and oilseed sesame seeds such as rapeseed and palm. Of these, soybean raw materials, particularly the cotyledon portion of soybeans, are particularly suitable, and defatted soybeans and okara containing a large amount thereof are particularly suitable.

  In the present invention, high-pressure steam is introduced to heat the raw material suspension. The method for introducing water vapor is not particularly limited, but it is desirable that heating be performed efficiently in as short a time as possible. A method in which high-pressure water vapor is continuously blown into a raw material suspension using a steam injector and heated. However, this is a preferable method because the temperature can be instantaneously increased to the target temperature.

  In the present invention, as a heating condition, high-pressure steam is blown into a suspension containing a raw material plant material and heated at 140 ° C. or higher. It is more preferable to perform this heating operation a plurality of times. In the case of this invention, compared with the method of heating the reaction container in a stationary state, since high-pressure steam is blown into the raw material suspension, a rapid share (stirring) is applied. By this phenomenon, the physical destruction of the plant cell wall component occurs, the water-soluble polysaccharide is easily eluted, and the extraction effect can be enhanced. Therefore, the effect of performing extraction more efficiently can be expected by performing heating a plurality of times. Speaking of high-pressure water vapor, it is preferable to use a water vapor pressure of 6 kg / cm 2 or more as a water vapor pressure from the viewpoint of obtaining a high temperature and a physical share. If the pressure is too low, a high temperature cannot be obtained, and the share at the time of introducing the steam becomes weak. An excessively high pressure increases the cost of the apparatus and makes it difficult to control the extraction.

Although cooling is performed after heating, in the present invention, it is preferable to cool at an instantaneous pressure reduction, particularly instantaneously reduced to atmospheric pressure after heating at least once in the present invention. In the heating at 140 ° C. or higher according to the present invention, the pressure in the extraction device is about the saturated vapor pressure at that temperature, and instantaneous pressure reduction (normally pressure reduction to atmospheric pressure) is performed from this pressure. Physical destruction of plant cell wall components occurs due to the blasting effect, and the extraction effect of the water-soluble polysaccharide can be further enhanced. As described above, the operation of reducing the pressure to the atmospheric pressure and cooling it is performed instantaneously, but this momentary time is usually about 1 second. If the heating operation as in the present invention is performed, the pressure is released at the moment of passing through the back pressure valve, and the pressure is reduced to atmospheric pressure, so that it does not take more than 1 second. On the other hand, cooling with a general plate does not cause a rapid pressure drop, and the extraction efficiency of water-soluble polysaccharides due to the blasting effect cannot be increased.

As described above, in the present invention, in order to extract the water-soluble polysaccharide more effectively, it is more effective to perform the heating a plurality of times, and as a cooling method after heating, the pressure is instantaneously reduced to atmospheric pressure. This method is particularly effective. About this heating and cooling method, it is cooled every time it is heated, a method of performing this a plurality of times, a method of cooling after performing a plurality of times of heating without sufficient cooling, a method of cooling after heating again, There is a method of cooling at the end after heating a plurality of times. Thus, although the timing of cooling at the time of heating is not limited, a great effect can be obtained by performing a cooling operation by instantaneously reducing the pressure to atmospheric pressure at least once after heating. Moreover, the same temperature may be sufficient as the heating temperature in several times of heating, and you may change temperature in steps. Any of the above-mentioned methods is a means that can increase the extraction efficiency of the water-soluble polysaccharide, but among them, every time heating is performed, the pressure is instantaneously reduced to atmospheric pressure, and this is performed a plurality of times. The method is the most effective means.

  The heating temperature is 140 ° C. or higher, preferably 150 ° C. or higher, more preferably 160 ° C. or higher. When the heating temperature is less than 140 ° C., the extraction effect is reduced, and the target water-soluble polysaccharide cannot be efficiently extracted in a short time. Further, the upper limit temperature during heating is not particularly limited, but as the heating temperature is raised, the decomposition reaction tends to proceed, the reaction time is reduced in order to suppress excessive decomposition and obtain a polysaccharide having the desired function. Control becomes stricter. When the heating temperature exceeds 190 ° C., decomposition of the water-soluble polysaccharide may proceed excessively, and heating at a temperature higher than this is not preferable.

  Although it does not specifically limit about the frequency | count of a heating, Usually, 3 to 4 times is enough. Even if the number of heating is further increased, the effect of increasing the extraction rate of the water-soluble polysaccharide is low only by increasing the number of steps.

  The upper limit of the number of times of instantaneous pressure reduction to atmospheric pressure and cooling is not particularly limited, but usually 2 to 3 times is sufficient.

The pH at the time of extraction is 3-7. Preferably it is 4-6. When the pH at the time of extraction is less than 3, it is susceptible to hydrolysis by an acid, and the extracted polysaccharide is reduced in molecular weight, making it difficult to obtain a water-soluble polysaccharide having a high function. On the other hand, when the pH exceeds 7, when the protein coexists in the raw material, the protein is decomposed and eluted together with the water-soluble polysaccharide, the purity of the polysaccharide is lowered, and the polysaccharide solution is reduced. The sugar tends to become cloudy or decomposed, and the amino acid reacts to turn brownish brown and tends to deteriorate the quality.

The total heating time is sufficient within 30 minutes. However, in order to carry out industrially efficient production, it is preferably within 20 minutes, more preferably within 10 minutes. If the time is longer, the decomposition rate becomes higher and the extraction efficiency of the water-soluble polysaccharide is improved, but it is not preferable because the molecular weight is lowered and the function is lowered. In this reaction, the minimum time is not particularly limited, but usually about 1 minute is necessary to obtain a sufficient amount of water-soluble polysaccharide extract.

  With regard to the molecular weight of the water-soluble polysaccharide, a certain degree of function can be obtained regardless of the molecular weight, but if the molecular weight is too large, the viscosity becomes high and handling becomes difficult. On the other hand, if the molecular weight is too small, the stabilizing function is weakened. The molecular weight is usually from several thousand to several million, and preferably in the range from 10,000 to 1,000,000.

  Hereinafter, the embodiments of the present invention will be described by way of examples. However, these are merely examples, and the spirit of the present invention is not limited by these examples. In the examples, both parts and% mean weight basis.

  In the reaction apparatus shown in FIG. 1, 14 parts of water was added to 1 part of degreased dried okara in the raw material tank 1, and the pH was adjusted to 5.0 with hydrochloric acid. The suspension from this okara is sent to the holding tube by the pump 7, steam using the steam injector 11 is introduced into the steam, the pressure is 7 kg / cm 2, and the water is heated instantaneously to 155 ° C., 2.5 After holding for a minute, the steam injector 12 is used again to introduce water vapor with a pressure of 7 Kg / cm 2, and the water is instantaneously heated to 165 ° C., held for 2.5 minutes and then cooled to 100 ° C. or lower with the cooling device 6, The slurry was received in the reaction solution receiver 5. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

  In the reaction apparatus shown in FIG. 1, 14 parts of water was added to 1 part of degreased dried okara in the raw material tank 1, and the pH was adjusted to 5.0 with hydrochloric acid. This suspension from okara is sent to the holding tube by the pump 7, and steam of a pressure of 7 kg / cm 2 is introduced using the steam injector 11 and heated instantaneously to 155 ° C. for 2.5 minutes. After the hold, use steam injector 12 again to introduce water vapor with a pressure of 7.0 Kg / cm 2, heat to 165 ° C momentarily, hold for 2.5 minutes, then instantaneously reduce to atmospheric pressure and cool Then, the slurry was received in the tank 2, and the slurry was received in the reaction liquid receiver 5 by the pump 8. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

  In the reaction apparatus shown in FIG. 1, 14 parts of water was added to 1 part of degreased dried okara in the raw material tank 1, and the pH was adjusted to 5 with hydrochloric acid. This suspension from okara is sent to the holding tube by the pump 7, steam is introduced into the holding tube using the steam injector 11, the pressure is instantaneously heated to 155 ° C, and held for 2.5 minutes. Then, the pressure was instantaneously reduced to atmospheric pressure to cool, and the slurry was received in the tank 3. The slurry is fed to the holding tube by the pump 9, and steam using the steam injector 13 is introduced into the steam at a pressure of 7 kg / cm 2, heated instantaneously to 165 ° C., held for 2.5 minutes, and then momentarily. The pressure was reduced to atmospheric pressure, the slurry was cooled, the slurry was received in the tank 4, and the slurry was received in the reaction liquid receiver 5 by the pump 10. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

<Comparative example 1>
14 parts of water was added to 1 part of degreased dried okara and the pH was adjusted to 5 with hydrochloric acid. This okara suspension was placed in an autoclave, heated to 165 ° C., held for 5 minutes, and then naturally cooled. The obtained slurry was again placed in an autoclave, heated to 165 ° C., held for 5 minutes, and then naturally cooled. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

<Comparative example 2>
In the reaction apparatus shown in FIG. 1, 14 parts of water was added to 1 part of degreased dried okara in the raw material tank 1, and the pH was adjusted to 5 with hydrochloric acid. This suspension from okara is sent to the holding tube by the pump 7, steam is introduced at a pressure of 7 Kg / cm 2 using the steam injector 11, heated instantaneously to 130 ° C., and held for 10 minutes. Then, the pressure was instantaneously reduced to atmospheric pressure to cool, and the slurry was received in the tank 3. The slurry is fed to the holding tube by the pump 9, and steam using the steam injector 13 is introduced into the steam at a pressure of 7 kg / cm 2, heated instantaneously to 130 ° C., held for 10 minutes, and then instantaneously atmospheric pressure. The pressure was reduced to a low temperature and the slurry was received. This operation was performed once more, and the slurry was received in the reaction solution receiver 5. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

<Comparative Example 3>
In the reactor shown in FIG. 1, 14 parts of water was added to 1 part of degreased dried okara in the raw material tank 1, and the pH was adjusted to 2.5 with hydrochloric acid. This suspension from okara is sent to the holding tube by the pump 7, and steam of a pressure of 7 kg / cm 2 is introduced using the steam injector 11 and heated instantaneously to 155 ° C. for 2.5 minutes. After the hold, steam of a pressure of 7 kg / cm 2 is introduced using the steam injector 12 and heated instantaneously to 165 ° C., held for 2.5 minutes and then cooled to 100 ° C. or lower with the cooling device 6, and the reaction solution The slurry was received in the receiver 5. The obtained slurry was separated by centrifugation, the supernatant was subjected to ethanol precipitation, and the precipitate was dried to obtain a water-soluble polysaccharide.

The results are compared and shown below.
[(1) Water-soluble polysaccharide yield]
The yield of the water-soluble polysaccharide was calculated from the amount of the water-soluble polysaccharide obtained with respect to the solid amount of the raw material. In the table, the gauge pressure is a pressure indicated by a pressure gauge, and the pressure gauge displays a pressure with the atmospheric pressure set to 0 MPa.

As in Example 1, by performing heating a plurality of times in a short time, the yield of the water-soluble polysaccharide relative to the solid content of the raw material was 26%, which was obtained at a high yield. Further, as in Examples 2 and 3, a water-soluble polysaccharide having a higher yield was obtained by reducing the pressure to atmospheric pressure instantaneously after heating and cooling. As can be seen from the pressure data, the operation of this example is performed at a pressure slightly higher than the saturated vapor pressure and very close to the saturated vapor pressure. Since the pressure is not so high, the extraction conditions are mild, and the equipment is not too large, it is a simple method. Furthermore, when the molecular weight distribution of the water-soluble soybean hemicellulose obtained from the method of Example was analyzed, it was confirmed that the molecular weight pattern was the same as that of the conventional extraction method. On the other hand, in the autoclave heating method as in Comparative Example 1, the yield was low even if the heating time was extended. As in Comparative Example 2, when the heating temperature was as low as 130 ° C., the yield was considerably low even when the heating / cooling method of the present invention was used. In Comparative Example 3, although the yield increased, as a result of analyzing the molecular weight pattern, it was found that the polymer fraction was decomposed and the molecular weight was considerably lowered.

[(2) Milk protein stability evaluation under acidic conditions]
Evaluation of milk protein stability under acidic conditions was carried out by the method disclosed in JP-A-5-262802. The method is as follows.

(Preparation of yogurt)
Nonfat dry milk was added to water (21%), heated and stirred, sterilized at 95 ° C, cooled, inoculated with commercially available plain yogurt as a starter, and fermented in a 38 ° C incubator. The fermented yogurt was homogenized using a stirrer. Then, it cooled to 10-15 degreeC.

(Preparation of stabilizer solution)
The water-soluble hemicellulose 2% solution was heated and stirred (stirred at 80 ° C. for 10 minutes) and then cooled to 25 ° C.

(Preparation of acidic milk beverage)
Sugar was added to water, then the above yogurt was added, and the pH was adjusted with lactic acid and an aqueous sodium citrate solution. Thereafter, the mixture was homogenized with a homogenizer (150 Kg / cm 2), stored in a refrigerator for 1 week after bottling. Each formulation was 20, 40, 7, and 33% stabilizer solution, yogurt, sugar, and water, respectively. The results are shown in Table 2.

(Table 2)
No. State after 7 days ――――――――――――――――――――――
Example 1 (-)
Example 2 (-)
Example 3 (-)
Comparative Example 3 (+)
―――――――――――――――――――――――
* Assessment of acid milk beverage after storage (-): Stable without separation. (+): Separated into two layers

It was confirmed that the water-soluble polysaccharide obtained by the method of the example has a milk protein stabilizing ability under acidic conditions and has a high function.
On the other hand, the water-soluble polysaccharide obtained by extraction at a low pH as in Comparative Example 3 has a low molecular weight, has no ability to stabilize acidic milk beverages, and has a high function even if the yield is high. Sexual polysaccharides cannot be obtained.

  The present invention is an efficient method for producing water-soluble polysaccharides, and provides an industrially advantageous method for producing water-soluble polysaccharides that are particularly excellent in useful functions in the food industry. According to the present invention, water-soluble polysaccharides useful in the food industry can be obtained efficiently.

It is explanatory drawing which showed the apparatus of the heating and extraction of polysaccharide.

Claims (3)

Including a step of introducing water vapor into a suspension of defatted soybean or okara with a water vapor pressure of 6 kg / cm 2 or more, wherein the pH is 3 to 7 and the heating temperature is 150 ° C. or higher and 190 ° C. Hereinafter , the total heating time is 1 minute or more and 30 minutes or less, the pressure is a saturated vapor pressure at the heating temperature, and a supernatant is obtained by solid-liquid separation of the slurry after the heating. A method for producing a water-soluble polysaccharide. The method for producing a water-soluble polysaccharide according to claim 1, wherein heating for introducing water vapor having a water vapor pressure of 6 kg / cm 2 or more is performed a plurality of times. Including a step of introducing water vapor into a suspension of defatted soybean or okara with a water vapor pressure of 6 kg / cm 2 or more, wherein the pH is 3 to 7 and the heating temperature is 150 ° C. or higher and 190 ° C. Hereinafter , the total heating time is 1 minute or more and 30 minutes or less, and the suspension of the defatted soybean or okara instantaneously from the saturated vapor pressure at the heating temperature after any heating in a plurality of heating times. A method for producing a water-soluble polysaccharide, characterized in that a supernatant is obtained by solid-liquid separation of a slurry after the pressure reduction through a step of reducing the pressure to atmospheric pressure.

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