JPH0440864A - A new method to produce mannan gel from konnyaku potatoes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a new method for producing mannan gel from konjac potatoes, and the technology of this invention can be applied to food materials other than konjac if necessary measures are taken. However, it can be applied to the production of gel-like foods containing glucomannan.

[Conventional technology]

The gelation of konjac occurs when the polysaccharide glucomannan, which is the main component of konjac flour and konjac potatoes, or the acetyl groups in its molecules are separated by the action of alkali, forming crosslinks between and within molecules through hydrogen bonds. It is based on the reaction.

Konnyaku products currently on the market include flat konnyaku, jade konnyaku, and shirataki when categorized based on their form, and classified into powdered konnyaku, sweet potato konnyaku, and other types based on their raw materials. In addition, in recent years, various food materials have been developed that utilize the gelling power of glucomannan, and all gelling by glucomannan is performed through the above-mentioned reaction.

The manufacturing method for konnyaku, a representative food product that uses glucomannan gel, varies depending on the raw materials and the type of product desired, but conventionally, konnyaku potatoes (hereinafter simply referred to as potatoes) are thinly sliced, dried, and then crushed. The powder is then called konnyaku powder. ) Add water to this, heat it slightly if necessary, and wait for the glucomannan particles to absorb water and expand sufficiently (1 to 3 hours), then add and mix the alkali, and use a mold to stand still for a certain period of time. The product is then allowed to stand and gel (at this time, heating may be applied to promote gelation). 12 Then, molding is completed with hot water, and further dealkalization with hot water is completed to obtain a product.

By the way, currently, konjac is mainly produced using the above-mentioned konjac flour as a raw material, and products made directly from konjac potatoes, so-called potato konjac, account for a small proportion, only a few percent.

Since potato konnyaku is processed from the whole potato, there is no need to remove impurities (flour), and because it contains starch and protein, it has high nutritional value and excellent flavor and color. However, the production of potato konnyaku This method requires a process of crushing the potatoes and, in some cases, a process of steaming the potatoes, making the manufacturing process complicated and requiring equipment for this process.Also, the biggest problem in manufacturing is the production of mannanase in the potatoes. The decomposition of glucomannan progresses due to contaminating microorganisms originating from the soil and soil.
This results in a decrease in gelling power. In the case of potato konnyaku,
Because of the structure of the potato, it takes longer for Glucomani/Nan to swell and hydrate than for powdered konjac. Furthermore, since it contains a large amount of nutritional components, it is extremely undesirable because there are concerns that bacteria will multiply rapidly, decomposing the glucomannan, and reducing gelling power. Heat treatment of raw potatoes is effective for sterilization and deactivation of enzymes, but care must be taken as excessive heating may adversely affect the quality of glucomannan.

[Invention or problem to be solved]

As mentioned above, glucomannan gel can basically be composed of glucomannan, water, and an alkaline substance, but compared to the simplicity of this composition, there are many steps required for gelation and it takes a long time. are doing. In particular, in the production of potato konnyaku, since the raw material potato tissue is maintained, it takes a long time to hydrate and swell the glucomannan particles, and the process is also complicated.

The reason for this is that in order to gel efficiently and completely, it is necessary to loosen the molecular chains of glucomannan, sufficiently hydrate it, and expose the acetyl groups. They had to wait for the molecules to gradually swell and become hydrated, which resulted in a long period of time. In other words, in conventional gelling methods, in order to obtain a homogeneous and highly viscous sol (glue-like state), glucomannan must be slowly hydrated over time and stirred gently. Even if you do something like increase the rotation speed, you won't get much of an effect.

Therefore, even if some improvements were made, the following problems could not be overcome as a practical technology.

(1) Complicated work.

(2) It takes a long time to get from raw materials to products.

(3) Production takes a long time and there are many chances for contamination (the number of raw particles of konjac flour is 103 to 10' pieces/g, which is high for a food material).

(a) Since it takes a long time to produce, the action of an enzyme (mannanase) unique to potatoes must be acknowledged.

(5) Since the process is complicated, it is difficult to maintain constant operating conditions, resulting in variations in product quality.

The above (3) and (4) cause glucomannan to be hydrolyzed and reduced in molecular weight, weakening the gelling power, making it difficult to obtain the desired quality, and (3) also causes spoilage. The reason for (5) is that the quality of the raw material, such as konjac flour, is not uniform and shows a wide range of physical properties, making it difficult to simplify the process, or it may directly affect product quality. Giving vine.

Despite these problems, the reason why the conventional method is widely used is that (1) it is a mild and simple method that can be used in small-scale operations.

(2) - By using tan konnyaku flour, there is no need to directly link the harvesting of raw potatoes to the production of finished konnyaku, which has operational advantages.

etc.

The present invention has been made in view of the above-mentioned state of the prior art, and provides a novel method for continuously producing potato konjac of constant quality in a short period of time using potatoes that retain plant tissue as raw materials. It is something to do.

[Means to solve the problem]

The present invention involves feeding konjac potatoes that retain their plant tissue to a twin-screw extruder, destroying the tissue to the extent that at least glucomannan particles are released, and then mixing and stirring in the presence of water. to hydrate the glucomannan particles to a desired degree to form a sol, simultaneously or after this, add an alkaline substance to the sol and disperse it, and remove it from the outlet of the twin-screw extruder; This is a new method for producing mannan gel from konnyaku potatoes, which is characterized by forming a gel from the resulting slurry.

According to the present invention, basically, as long as the potato is cut into a size that can be fed into the extruder, integrated production is possible. The subsequent strong kneading significantly shortens the hydration time, in other words, it is possible to shorten the hydration time from several hours to just tens of seconds or minutes, achieving stable quality, which was previously difficult. Potato konjac can be manufactured with high productivity.

That is, in order to solve the above-mentioned problems, the present inventors conducted intensive research on the gelation behavior of glucomannan, and found that a twin-screw extruder was used despite using raw materials that retain plant tissue. The inventors have discovered that it is possible to perform hydration and swelling in an extremely short time by liberating glucomannan particles in the tissue, followed by wet kneading using a strong stirring force, which led to the present invention. It is.

The above process can be carried out within the barrel of a single twin-screw extruder. In other words, it is only about 1 m (2
In the barrel of the shaft extruder (of course there will be holes depending on the model, etc.), the process of destroying the potato tissue and exposing the glucomannan particles, the process of kneading the glucomannan particles to form a sol, and the process of adding and mixing an alkaline substance. The whole process of producing sweet potato konnyaku, which consists of
It can be completed within a few minutes.

As described above, the feature of the present invention is that by using a raw material that retains the potato structure, which was considered undesirable in the past, the L-processing can be effectively carried out in one step in the barrel of a twin-screw extruder. However, in order to understand the invention, the gelation behavior of glucomannan particles in the prior art will be explained next.

The particle size distribution of commercially available konjac flour is wide, several 100 μm.
There is a mixture of particles of various sizes, from large particles to fine particles of several micrometers. In addition, the particle size of glucomannan particles in konnyaku potatoes is wide within the range of the company'v! , distributed throughout the darkness. Although it is naturally thought that there are differences in the dissolution rates of glucomannan particles having different particle sizes, there was also a large difference in the time required to reach the maximum viscosity in the tests conducted by the present inventors. The results are schematically shown in FIG.

It can be seen that in the conventional manufacturing method, a mixture of five large and small particles is used as a raw material, and the timing of adding an alkaline substance and starting gelation can have a great influence on the gel properties.

For example, at the point when large particles are completely hydrated and the particle size reaches its maximum (C), the viscosity of small particles has already decreased, and the gelling ability of small particles is not fully utilized. It means that it is not. Conversely, when the viscosity of small particles reaches its maximum (A
), when the large particles have finally begun to hydrate and the viscosity is about to rise, if alkali is added at this point, the undissolved portion of the large particles will be wasted without participating in gel formation.

As described above, according to the conventional technology, the progress of gelation differs depending on the size of the particles, and the original gelling ability is not fully utilized, and it takes a long time for the particles to absorb water and the glucomannan molecules to loosen. However, there are problems in the efficiency of gel formation when sol-forming or gel-forming glucomannan particles from the state of glucomannan particles, such as the need to stir until these molecules are sufficiently dispersed in water to form a sol.

Furthermore, when using a raw material that retains the potato structure, stability and uniformity will deteriorate due to the necessary process to expose glucomannan particles from within the structure, compared to the gelation behavior of konjac flour mentioned above. I will do it.

In the present invention, the pulverization of the twin-screw extruder,
By using functions such as kneading, pressure feeding, and heating, the structure is destroyed at least to the extent that glucomannan particles are liberated, and then, by performing strong stirring and kneading in the presence of water, the glucomannan molecules are loosened. Without waiting, it turns into a sol all at once. A gel can be formed by adding an alkaline substance to this sol and performing a deacetylation reaction, but since the sol is formed in an extremely short time, the gel formation period can be significantly shortened.

In addition, an alkaline substance is allowed to exist when the potato tissue is crushed,
It is possible to achieve uniform and rapid dispersion of the substance.

The present invention will be explained in detail below.

First, the raw material that can be used in the present invention is a konjac potato that retains the tissue of a plant, and glucomannan particles are scattered in the potato tissue. however,
Konnyaku potatoes used as raw materials are not limited to fresh ones; frozen ones can also be used. Furthermore, the form of supply to the two-axis extruder is as follows:
It can be selected as appropriate depending on the type of extruder used. For example, raw potatoes can be cut into convenient sizes (about a few centimeters square) that can be fed into the feeder of an extruder, or raw potatoes can be boiled for several minutes using a hot kneader, etc. You may also cut and serve in the same way.

Next, the pulverization, kneading, pressure feeding, and
The twin-screw extruder that can be used in the present invention may be a known twin-screw extruder that uses a heating function to solize the glucomannan particles in the konjac potato, and that can be cooled or heated. Any material can be used as long as it has a structure in which the raw material supplied by the rotation of a screw in the barrel is extruded from a die provided at the outlet while applying heat and strong stirring force.

The inside of the barrel of a two-screw extruder can be functionally divided into three main parts depending on the screw arrangement. The first part is the part where the potato tissue is destroyed to expose the glucomannan particles, the second part is the part where the glucomannan is kneaded and hydrated and swelled to form a sol, and the third part is where the alkaline substance is added and mixed.

Now, the raw material supplied from the feeder may be only the cut material, but it may also be supplied together with water.

That is, the presence of water is not necessarily required when releasing glucomannan particles in the raw material from potato tissue, or when hydrating the released glucomannan particles to form a sol, 10 When 100 times the amount of water is present, pulverization, kneading, pressure feeding, and heating using a twin-screw extruder work effectively.

At this stage, it is important to consider whether it is preferable for the above-mentioned function in the barrel to act uniformly on the raw material.Since the present invention uses a raw material with a potato structure, if konjac flour or the like is used, it will be difficult to transport it within the barrel. It takes an appropriate amount of time, and a more effective kneading effect is applied, allowing for uniform processing.

There are no particular restrictions on the temperature of each barrel, and there is no problem as long as it is 0°C or higher.

In the present invention, in the first part, destroying the tissue to the extent that at least glucomannan particles are released means that the glucomannan particles scattered in the potato tissue are destroyed by the destruction of the surrounding potato tissue. The particles are exposed at least on the surface of the broken pieces, and since the particles in the potato tissue are relatively hard, they are held relatively stably even if other tissues are crushed. At least means that the particles may be further crushed into fine particles, but 2
Particle destruction is less likely to occur in the processing of the axial nixtruder, and harsh conditions are not required for destruction. That is, it is sufficient that the glucomannan particles are destroyed at least to the extent that they are exposed on the surface of the broken pieces and form a sol.

In the present invention, since the potato tissue is finely crushed in a short time as described above, it does not take a long time for the glucomannan particles in the tissue to absorb water and swell.It depends on other conditions, but from 30 seconds to IO minutes at most. It's only a matter of degree. Furthermore, the degree of symmetry is high and uniform. Since it is a uniform sol, the uniformity of the gel formed also appears to be high. In other words, this is due to the characteristics of glucomannan, which is a raw material, that it takes a long time to swell and hydrate because it is a polymeric substance, and the time required for hydration varies greatly depending on the size of the particles. It is possible to solve the problems of the conventional technology.

The sol obtained at this stage is homogeneous and highly viscous, but the viscosity etc. may be appropriately set according to the quality of the desired gel product. Here, a homogeneous sol refers to a state in which no unhydrated glucomannan particles remain in the sol, and the degree of sol formation can be determined by an increase in viscosity or by visual observation.

Next, an alkaline substance is mixed into the sol obtained above.

In this third part, the alkaline substance is uniformly dispersed in the sol to allow the glucomannan to undergo deacetylation. The alkaline substance is one that adjusts the pH of the sol to 9.5 or higher, preferably about 11 to 12.5, such as calcium hydroxide, sodium hydroxide, sodium carbonate, etc.
Although any known alkaline substance can be used, milk of lime is usually preferably used.

The alkaline substance may be added in the barrel after the sol is formed as described above, but it is also possible to add the alkaline substance in advance to the water added during sol formation, or to add an alkaline solution separately. It is also possible to add sol and perform alkaline substance mixing in parallel. This is because in the present invention, the operations up to mixing the alkaline substance can be carried out in a short time by continuously carrying out the operations within the barrel of one twin-screw extruder. In other words, it is possible to form a sol and mix the alkaline substance within the time period from when the alkaline substance is added until gelation substantially starts, usually within 1 to 2 minutes, and then discharge the sol out of the barrel. An alkaline substance can be present during solization.

The degree of progress of gelation at this stage should be set appropriately depending on the physical properties of the desired gel product, the presence or absence of post-treatment, etc.
Normally, after the above-mentioned twin-screw extruder treatment, molding, coagulation, etc. are performed to produce a product, so an alkaline substance is added to the slurry obtained after mixing, and the gelation of the slurry is suppressed to the extent that it can be molded and solidified afterwards. However, if gelation begins and the subsequent coagulation force weakens, the gel strength of the resulting gel product will decrease. It is also possible to pass the slurry discharged from the barrel through a die having a desired shape and gel it immediately after discharge; in this case, it is preferable to heat the tie temperature to 70 to 100°C. Since the degree of gelation progress is determined by the pH of the slurry, temperature, time, etc., these conditions may be set so that the extruder treatment is completed at a desired degree.

In order to obtain a gel product, molding and coagulation or heating at that time is effective for deactivating and sterilizing natural enzymes and for gel formation. That is, by placing the slurry obtained after the twin-screw extruder treatment in a desired container and leaving or heating it for several minutes at room temperature or in hot water at 70 to 100°C, gelation is completed and the desired gel product is obtained. Moreover, a desired external shape can be given by selecting the shape of the die exit.

It is optional to promote gelation or dealkalize with hot water.

Furthermore, in carrying out the present invention, products can be obtained from any part of the barrel without adding any auxiliary materials, so new konjac-related foods can be prepared.

As explained above, in the present invention, konnyaku potato with retained potato structure is used as a raw material, and the glucomannan is forcibly hydrated in a short time, kneaded to create a sol, and gelled. This is an innovative manufacturing method that allows integrated production from raw materials to products in a matter of tens of seconds or minutes, so gel formation is achieved extremely efficiently regardless of the type of raw materials (product type, particle size, etc.). be able to.

Therefore, according to the present invention, the following effects can be obtained in practice.

There is no time for microorganisms originating from food materials other than glucomannan, such as konjac potatoes and seaweed powder that is sometimes added during konjac manufacturing, to proliferate, and there is a similar risk of quality deterioration due to the action of the enzyme mannanase. excluded for a reason. In other words, according to the method developed here, glucomannan can be gelled before its quality deteriorates (such as a decrease in viscosity), so the quality of the raw material is not compromised and 100% can be utilized. Become.

In addition, in the method of the present invention, glucomannan particles are forcibly kneaded by the rotation of a screw to form a homogeneous sol, regardless of the size of the particles or whether they are made from powder or sweet potatoes. Therefore, the size of particles in the raw material has no effect on the quality of the sol. Until now, glucomannan particles have been considered to be of high quality if they are large, and even in the case of commercially available konjac flour, those with a high ratio of large particles are highly valued, while those containing many fine particles are considered to be of poor quality. However, according to the present invention, glucomannan particles are
Regardless of their size, they are hydrated and swollen by the extruder's strong stirring force, so the quality of the raw materials has almost no effect on the quality of the product.

In addition, the method of the present invention does not cause heat generation during pulverization, mechanical damage, or decrease in viscosity or solubility caused by chemical changes after pulverization due to the conventional pulverization of konjac flour. Since the raw materials are forcibly homogenized in a short time by strong crushing and pumping forces in the presence of water, negative effects on quality can be eliminated.

In addition, in the conventional method, it was difficult to stabilize the quality and there was little variation in the product, but the method of the present invention allows mixing of glucomannan particles by simply changing the combination of screws used and the rotation speed. The degree can be adjusted, and it is possible to freely produce gels with coarse or dense structures.

Furthermore, since the method of the present invention is continuous and can perform gel formation in one step, product quality including sanitary aspects can be stabilized and equipment can be simplified. Incidentally,
According to the present invention, the manufacturing time that conventionally required several hours can be reduced.
The time can be shortened to just a few minutes, and the economical and equipment-wise effects are enormous.

In addition, in the present invention, the entire process is carried out in the barrel of a single twin-screw extruder, but the sol can also be taken out from the barrel after sol formation, and this sol is better than the sol obtained by the conventional method. Since there is far less risk of microbial contamination, it can be stored for quite a long time by freezing or refrigerating, and the amount of production can be controlled.

In addition, until now, the production of potato konjac has been accompanied by technical and equipment difficulties, and for this reason, pure potato konnyaku is no longer produced, or according to the present invention, sweet potato konjac made from 100% sweet potato konnyaku is no longer produced. High-quality konjac can be easily made with almost no waste of raw materials. In addition, because the grinding force and pumping force are strong, a sol with a higher viscosity than conventional methods can be obtained, so the ratio of glucomannan to water can be set relatively freely (80 to 10% by weight). This makes it possible to produce konjac products with high dietary fiber and nutritional value.

Furthermore, in the method of the present invention, the presence of food materials other than glucomannan does not hinder the grinding and pulverization of potato tissue, so any food material can be uniformly dispersed and mixed in the sol. It can also be applied to the production of new types of konnyaku-related products.

Nearly 10 years have passed since the 2-axis extruder was introduced as a multi-functional food processing machine. meanwhile,
Many research results have been obtained by utilizing some of the various functions of the two-axis extruder, and many patents have been issued. However, the grinding, melting, mixing,
It can be said that there is no example yet where the many functions such as kneading and pressure feeding are fully utilized and applied to food processing. The basis of konjac production is to thoroughly stir glucomannan to hydrate it, and then evenly contact it with alkali to cause the sol to gel conversion.The many functions of the twin-screw extruder are It can be said that it is most suitable for manufacturing.

The method of the present invention fully utilizes the functions of a twin-screw extruder, and is a simple and efficient method that opens up a completely new aspect of konjac production, particularly konjac production from potatoes.

〔Example〕

Examples of the present invention are shown below. In addition, about 1.5c of raw konnyaku potatoes (average weight 354g) are used as raw materials here.
Konjac potatoes cut into m-square dice and konjac potatoes boiled in a hot kneader for 60 minutes and then cut were used. In addition, an FT60-N type twin-screw extruder (Mitsubishi) was used as the device, and the screw arrangement was the part for crushing the potato, exposing the glucomannan particles, and kneading [(F(
(Correct, 180am), F (Correct, 1801m), F (Correct, 6
0+am), K(kneading, 2401m)], the part where alkali is added [F(positive, 18hm), KF(kneading forward, 60mm)], the part where alkali and sol are uniformly mixed [(F(positive) , 180mm)
, K to ding, 60o+m), R (reverse 60au++
) ], and the settings are divided into three parts based on functionality. Note that the screw rotation speed was increased by 200 revolutions.

Example 1 Raw konnyaku potatoes cut into cubes and distilled water were supplied from the raw material input port at a rate of 50 g/min and 200 m1/min, respectively, and the machine was operated for 1 to 2 minutes until a homogeneous sol came out from the discharge port. 10% from the supply port in the middle of the barrel.
Calcium hydroxide suspension was added at a rate of 10 ml/min. A few seconds after adding the alkali, a stable semi-gel slurry with a homogeneous viscosity and no undissolved matter was obtained, and when this was left in a shaped container for several minutes (at room temperature), it completely gelled. It was approved to do so. In this example, the barrel was not heated but was tested at room temperature, and there was almost no rise in temperature of the raw material during treatment. The gel after solidification is highly elastic, and its average analysis value is p) 1i2.0 solid content 4.8
%, ash content 0.73%, Ca2378PI)01.

Example 2 The process was carried out under the same conditions as in Example 1, except that the barrel of the part corresponding to the crushing of konnyaku potatoes was heated to 70°C.
The raw material (item fA7oC) immediately obtained from the discharge port was darker in color than in Example 1 and had a strong amine odor as well as the characteristic odor of konjac potatoes, but the amine odor almost disappeared after being left for a while. The gel was completely formed after a few minutes. The gel after solidification is highly elastic, and its average analysis values are pH 11.1, solid content 4.83%, ash content 0.67%,
Ca was 1917 ppm.

Example 3 The treatment was carried out under the same conditions as in Example 1, using raw materials that had been previously heat-treated in a hot kneader. A more homogeneous sol (at room temperature) or a shorter time (about 1 minute) than with raw konnyaku potatoes.
Obtained with. The gel was completely formed after a few minutes. The gel after solidification is highly elastic, and its average analysis value is pH 11,
9. Solid content 4.78%, ash content 062%, CCa2427
It was pp.

〔Effect of the invention〕

As explained above, according to the present invention, glucomannan particles in the potato tissue are liberated and kneaded using a twin-screw extruder, so hydration and swelling are completed in a short time, reducing variations in the raw material. You can obtain a product of constant quality regardless of quality. Furthermore, since the method of the present invention can be carried out continuously using a single twin-screw extruder, there is little variation in products, production efficiency can be improved, and equipment can be simplified.

On the other hand, since no flying powder is generated during manufacturing, the yield is improved.
Furthermore, it is possible to reduce microbial contamination and produce products with rich variations. Further, according to the present invention, it is possible to appropriately adjust the glucomannan content by increasing the glucomannan content, thereby making it possible to produce novel foods.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the relationship between the change in viscosity of konjac flour over time and the particle size of glucomannan particles in the flour.

Claims (1)

[Claims] 1. Feeding the konjac potato that retains the tissue as a plant body to a twin-screw extruder to destroy the tissue to the extent that at least glucomannan particles are released, and then in the presence of water. The glucomannan particles are hydrated to a desired degree by mixing and stirring to form a sol, and at the same time or after this, an alkaline substance is added to the sol to disperse it and taken out from the outlet of the twin-screw extruder. , a new method for producing mannan gel from konnyaku yam, which is characterized by forming a gel from the resulting slurry. 2. Claim 1, wherein the konjac potato is raw konjac potato.
The method described in. 3. The method according to claim 1, wherein the konjac potato is a boiled konjac potato. 4. The method according to claim 1, wherein the amount of water present during the mixing and stirring is 10 to 100 times the unit weight of glucomannan.