JP5754038B2 - Granular salt and method for producing the same - Google Patents

Description

The present invention relates to a granular salt and a method for producing the same, and more particularly to a granular salt with improved taste and a method for producing the same.
In Japan, a plurality of anion exchange resin membranes and cation exchange resin membranes are alternately arranged between a pair of electrodes at a distance from each other, seawater is filled between the membranes, and a DC voltage is applied between the electrodes. The brine is obtained by concentrating seawater using the ion exchange resin membrane method. The obtained brine is put into a vacuum evaporator, and the water is evaporated from the brine in the vacuum evaporator to crystallize the granular salt (salt). A salt production method has been adopted.

  However, in the granular salt produced by such a method, the NaCl content is 99% by mass or more compared to the granular salt obtained by the so-called sun-made salt method, which is obtained by solar heat and wind. On the other hand, since the content of mineral components contained in seawater is very small, less than 1% by mass, there is a problem that the user is allowed to taste only the extreme saltiness.

  Therefore, the granular salt manufactured using the salt production method has been reviewed, and for example, Patent Document 1 described later discloses the following method.

  That is, a sun drying facility including a seawater evaporation facility that evaporates seawater by the sun and a deposition facility that deposits the salt crystallized by the seawater evaporation facility is installed. In the seawater evaporation facility, a ceramic pool with a depth of about 20 cm is provided on the heat insulation layer, and the seawater is introduced into the pool so that the water depth is about 2 cm. The granular salt is crystallized by evaporating the water in the sun for several days.

The above-described deposition facility comprises a ceramic pool provided on the heat insulating layer and a thatched roof covering the pool, and the granular salt crystallized as described above in the seawater evaporation facility is pooled. The operation of depositing in the inside is repeated to deposit the granular salt, which is dried for about one year in the sun.

  As a result, a granular salt having 90% by mass of NaCl, 5% by mass of minerals, and 5% by mass of water is obtained.

JP-A-8-38092

  However, in the conventional salt production method and the granular salt obtained by the method, the mineral content of the granular salt can be increased, but the taste of the obtained granular salt cannot be adjusted. There was a problem.

This invention is made | formed in view of such a situation, Comprising: Content of a mineral is large and provides the granular salt which improved the taste exhibited, and its salt manufacturing method.

Since the minerals in seawater precipitate on the surface of sodium chloride crystals, the inventors of the present invention have a relatively large surface area per unit mass if the crystal particle size is relatively small, and thus the unit of crystals. As a result of diligent investigation paying attention to the fact that the proportion of minerals contained per mass can be increased, when the inner surface of the evaporation tank has a certain roughness, it is also possible to maintain a constant amount of water stored in the evaporation tank. The present invention has been completed by obtaining the knowledge that the proportion of a relatively small particle size can be increased in the obtained crystal when the depth is set to a depth of 5 mm.

In the salt production method for obtaining the granular salt according to the present invention, the raw water obtained from seawater is heated and primary concentrated to a specific gravity of 1.12 or more and 1.22 or less . reserved in, which a salt production method to crystallize the particulate salt secondarily concentrated to a specific gravity of 1.24 or more 1.29 or less by heating, the average inner surface of 0.1μm or 0.4μm or less Secondary concentration is carried out by storing the primary concentrated solution in a salt crystallization tank having a surface roughness, and / or the salt crystallization tank is at least 19% of the depth dimension of the salt crystallization tank 50 The primary concentrated solution is stored so as to have a depth of not more than%, and the secondary concentration is performed. From the salt obtained by the secondary concentration, the salt of the crystal having a diameter of 1 mm or less is fractionated. To do.

When the primary concentrated liquid is stored in a salt crystallization tank having an inner surface with an average surface roughness of 0.1 μm or more and 0.4 μm or less and secondary concentration is performed, the surface roughness of the inner surface of the salt crystallization tank is Since the plurality of fine irregularities constituting the film function as nucleation sites for generating crystal nuclei, the rate at which fine crystal particles are generated from each nucleation site is improved. Thus, it is considered that the crystal content of the crystal having a relatively small particle size such as a diameter of 1 mm or less is increased in the crystallized salt.

In addition, when the primary concentration liquid is stored in the salt crystallization tank so that the depth is 19% or more and 50% or less of the depth dimension of the salt crystallization tank , As the depth of the primary concentrated liquid stored in the tank increases, the crystallization speed decreases, and as a result, the grain size of the crystallized crystal gradually decreases. Thus, primary concentration solution stored in ShioAkira析用tank, when 50% or less of the depth of 19% or more of the depth of the ShioAkira析用vessel, the particle size such diameter 1mm or less is relatively The content of small crystals can be increased.

Here, in a crystal having a relatively small particle size, the contents of Mg and Ca are higher than crystals having a larger particle size. In these Mg and Ca, since magnesium chloride and calcium sulfate are comprised and sweet taste is exhibited, the taste which can be exhibited can be improved .

The present inventors have studied intensively, when the average surface roughness of the inner surface of ShioAkira析用tank is 0.1 mu m or more 0.4μm or less, there is relatively small particle size such as 1mm or less in diameter The crystal content could be increased.

  On the other hand, when a salt crystallization tank having an average surface roughness of less than 0.1 μm was used, the effect of increasing the content of crystals having a target particle size did not work.

Further, when a salt crystallization tank having an average surface roughness of more than 0.4 μm is used, there is a disadvantage that the crystallized salt adheres to the inner surface of the salt crystallization tank.

The present inventors have studied intensively, particle size primarily concentrated liquid stored in ShioAkira析用tank, is greater than or equal to 19% of the depth of ShioAkira析用tank, having a diameter say a 1mm or less The crystal content of can be increased.

  On the other hand, when the introduction amount of the primary concentrated liquid exceeds 50% of the depth dimension of the salt crystallization tank, the crystal of the crystallized salt is removed from the upper edge of the salt crystallization tank before the secondary concentration is completed. In this case, the secondary concentrated liquid leaks out of the salt crystallization tank due to the capillary action of the extended crystals.

  In the salt production method of the present invention, a crystalline salt having a diameter of 1 mm or less is fractionated from the salt obtained by secondary concentration.

In the case of a crystalline salt having a diameter of 1 mm or less, the content of Mg and Ca is higher than that of a crystalline salt having a larger particle diameter. In these Mg and Ca, since magnesium chloride and calcium sulfate are comprised and sweet taste is exhibited, the taste which can be exhibited can be improved .

In the salt production method of the present invention, the primary concentrated solution is subjected to primary concentration until the specific gravity of the raw material water reaches a value of 1.12 or more and 1.22 or less , and the crystals crystallized by this primary concentration are removed. It is obtained by doing.

  When the specific gravity of the raw material water reaches 1.12, calcium sulfate starts to crystallize, and when the specific gravity of the raw material water reaches 1.22, the crystallization of calcium sulfate stops.

  Such calcium sulfate is easily fixed to the inner surface of the tank, and calcium sulfate has a very low thermal conductivity. Therefore, when calcium sulfate adheres to the inner surface of the tank, the primary concentration efficiency of the raw material water by heating is extremely high. In order to decrease, it is necessary to remove the fixed calcium sulfate from the tank. However, such a removal operation requires a lot of labor and is difficult to remove completely.

If it performed without performing such a primary concentration secondary enrichment, but before a similar phenomenon occurs by advance crystallization and removal of calcium sulphate thus by the primary concentration, secondary It is possible to prevent calcium sulfate from adhering to the inner surface of the salt crystallization tank used for concentration. Thereby, secondary concentration can be carried out efficiently.

On the other hand, calcium sulfate is a light sweet ingredient, and by setting the specific gravity at the end of primary concentration to a value from 1.12 to 1.22, the amount of calcium sulfate according to the user's preference is primary. It can be made to remain in the concentrate.

In the salt production method of the present invention, the secondary concentration is performed until the specific gravity of the primary concentrated solution reaches a value of 1.24 or more and 1.29 or less.

  When the specific gravity of the primary concentrated liquid becomes 1.24 or more, sodium chloride is crystallized. At this time, minerals such as calcium sulfate, magnesium chloride, potassium chloride, and magnesium sulfate are crystallized on the surface of the crystallized sodium chloride crystal. Analyze. Here, calcium sulfate has a light sweetness, magnesium chloride has a sweet umami, potassium chloride has a refreshing acidity, and magnesium sulfate has a deep bitter taste. Therefore, the secondary concentration is stopped when the final product reaches a specific gravity value set in advance so as to achieve a taste balance according to the user's preference.

On the other hand , the salt production method according to the present invention is characterized by fractionating a crystal salt having a diameter of 1 mm or less by sieving as required.

Thus, since the salt of the crystal having a particle diameter of 1 mm or less is separated by sieving, it can be carried out with simple equipment, and the equipment cost can be reduced.

Further, the granular salt according to the present invention obtained by the salt production method is composed of particles having a particle size of 0.25 mm or more and 2 mm or less, and the total of calcium, magnesium, potassium and sulfur is on the crystal surface of the particles. 4% to 22% by mass with respect to the total weight of the crystal.
Thus, the granular salt according to the present invention obtained by the salt production method is composed of particles having a particle size of 0.25 mm to 2 mm, and the total of calcium, magnesium, potassium and sulfur is granular on the crystal surface of the particles. The presence of 4 mass% to 22 mass% of the total weight of the salt crystals increases the content of minerals, and the various minerals are complemented to present various tastes, resulting in a rich taste. It is thought that you can.

It is a flowchart which shows the procedure of the salt making based on this invention. It is a flowchart which shows the procedure of the salt production which concerns on 2nd Embodiment. It is a flowchart which shows the procedure of the salt production which concerns on 2nd Embodiment. It is an experimental result showing the relationship between the crystallization temperature and yield of the granular salt which concerns on this invention. It is a verification result of the mineral element contained in the granular salt concerning the present invention. It is a SEM photograph of the surface of a salt particle of granular salt concerning the present invention, and a fracture surface. Surface analysis of the surface, fracture surface, and radial direction of the salt particles. Surface analysis of the surface, fracture surface, and radial direction of the salt particles. It is a surface analysis and a line analysis of the interface produced by the fracture | rupture of SS size granular salt. It is an X-ray diffraction pattern of the granular salt of the present invention. Secondary concentration was performed using a salt crystallization tank with brazing treatment and a salt crystallization tank without brazing treatment, and the results of measuring the yield of each crystallized crystal by particle size were measured. It is a histogram to show. It is a graph which shows the result of having measured the average surface roughness of the tank for various salt crystallization. It is a histogram which shows the result of having measured the yield according to the particle size of the crystallized crystal which performed secondary concentration by varying the depth of the primary concentrated liquid stored in the salt crystallization tank. Content ratio of a plurality of component elements constituting the salt of SS size according to the present invention obtained in Example 2 and content ratio of a plurality of component elements constituting a salt of another size screened in Example 2 It is a graph which shows the result of having measured. It is a graph which shows the result of having compared and examined the sample of the example of this invention, and the sample of the comparative example by the two-point identification and preference test method. The content of a plurality of component elements constituting the SS-size salt according to the present invention produced by using a primary concentrate having a specific gravity of 1.17, and other sizes sieved in the production process It is a graph which shows the result of having measured the content rate of the some component element which comprises salt. The content of a plurality of component elements constituting the SS-size salt according to the present invention produced by using a primary concentrate having a specific gravity of 1.22, and other sizes screened in the production process It is a graph which shows the result of having measured the content rate of the some component element which comprises salt.

(First embodiment)
FIG. 1 is a flowchart showing a procedure for salt production according to the present invention.

  As shown in FIG. 1, raw water is prepared (step S1).

  Here, as raw material water, seawater, brine obtained by concentrating seawater, or mixed water of seawater and brine can be used. In addition, flooded water is a membrane concentration method that concentrates seawater using a membrane such as a reverse osmosis membrane, a vacuum flash evaporation method that sprays seawater under reduced pressure to evaporate water, and sprinkled seawater is on the surface of bamboo or nets. A method obtained by various methods such as a flow-down method for evaporating water during flow and a method for evaporating the water in seawater introduced into the salt fields by the sun can be used. Such raw material water is filtered to remove contaminated impurities as necessary. Moreover, the pH of raw material water is adjusted to neutral vicinity as needed.

Then storing such raw water into the evaporation vessel (step S2), the heating was started to the primary evaporate water concentrate from raw water raw water in the evaporation chamber by solar or heater (step S3), and the specific gravity of the primary concentrate is carried out primarily concentrated until it is determined to have reached the value from 1.12 to 1.22 (step S4). When the specific gravity reaches the value from the 1.12 to 1.22, and terminates the primary enrichment (step S5), and crystallized calcium sulfate (CaSO ₄₎ and a the solid-liquid separation primary concentrate ( Step S6).

  Here, heating raw material water by sunlight means adding heat to raw water by solar heat, regardless of whether it is outdoor or indoor. Therefore, when an evaporating tank is installed in a greenhouse, it is preferable because solar heat can be used efficiently.

  By the way, when raw material water is concentrated and specific gravity reaches 1.12, calcium sulfate begins to crystallize, and when the specific gravity of raw material water reaches 1.22, crystallization of calcium sulfate stops.

  On the other hand, since calcium sulfate is easy to adhere to the inner surface of the concentration tank, and calcium sulfate has a very low thermal conductivity, if calcium sulfate adheres to the inner surface of the concentration tank, the concentration efficiency of raw water by heating Therefore, it is necessary to remove the fixed calcium sulfate from the concentration tank. However, such removal work requires a lot of labor and is difficult to remove completely.

However, when carrying out the primary concentrated at a temperature below about 30 ° C., for crystallization of calcium sulfate as needles, it is prevented from adhering to the inner surface of the condensation tank, easily removed from the concentrate tank to the outside be able to.

When performing the secondary concentrate to be described later without performing such primary concentration, but before a similar phenomenon occurs by advance crystallization and removal of calcium sulphate thus by the primary concentration, secondary It is possible to prevent calcium sulfate from adhering to the inner surface of the salt crystallization tank used for concentration. Thereby, secondary concentration can be carried out efficiently.

By the way, calcium sulfate is a light sweet component, and the specific gravity of the primary concentrated liquid at the end of the primary concentration is 1.12 to 1.1 so that the amount according to the user's preference remains in the primary concentrated liquid. Set the value up to 22.

  Here, the solid-liquid separation between the crystallized calcium sulfate and the concentrated liquid can be performed by filtering off the calcium sulfate, and the calcium sulfate is allowed to settle and the supernatant concentrated liquid is discharged into another container. Can also be performed. Furthermore, centrifugation may be used.

Next, the primary concentrated solution thus obtained is stored in a salt crystallization tank (step S10), and the raw water in the evaporation tank is heated to a temperature of less than 60 ° C. by sunlight or a heater. Then, secondary concentration for evaporating water from the primary concentrated solution is started (step S11), and the secondary concentration is determined until the specific gravity of the secondary concentrated solution reaches a value from 1.24 to 1.29 (step S12). performing concentrated, if it is determined to have reached the specific gravity of this, ends the secondary concentrate (step S13).

Here, ShioAkira The析用tank, the following average surface roughness 0.4μm or 0.1 mu m, using a material having a contact region of the primary concentrated solution of its inner surface.

  When a salt crystallization tank having an inner surface with such an average surface roughness is used, since a plurality of fine irregularities formed on the inner surface function as nucleation sites, the crystallized salt has a diameter. It is considered that the content of crystals having a relatively small particle size such as 1 mm or less increases.

On the other hand, in the case of using a salt crystallization tank having an inner surface with an average surface roughness of less than 0.1 μm or greater than 0.4 μm, the effect of increasing the content of crystals having the above-mentioned particle diameter In particular, in the latter case, the crystallized crystals are fixed in the brazing-processed brazing of the salt crystallization tank, which makes it difficult to recover the crystals.

  Various materials such as a resin material, a metal material, a metal oxide material, or a ceramic material can be used as the material for the salt crystallization tank. For example, a polystyrene resin or hard aluminum can be used.

Incidentally, when performing such secondary concentration is maintained at a temperature below 60 ° C. The temperature of the secondary concentrate as described above. When the liquid temperature at the time of secondary concentration is 60 ° C. or higher, calcium sulfate crystallizes as a ½ hydrate, which deteriorates the quality of the product obtained. However, when the liquid temperature at the time of secondary concentration is less than 60 ° C., calcium sulfate crystallizes as a dihydrate, thereby preventing the quality of the product from being deteriorated.

  On the other hand, as described above, sodium chloride crystallizes when the specific gravity of the secondary concentrated liquid becomes 1.24 or more. On the surface of the crystallized sodium chloride crystal, calcium sulfate, magnesium chloride, potassium chloride, and Minerals such as magnesium sulfate crystallize out. Here, as described above, calcium sulfate has a light sweetness, magnesium chloride has a sweet taste, potassium chloride has a refreshing acidity, and magnesium sulfate has a deep bitter taste. Therefore, the secondary concentration is stopped when the final product reaches a specific gravity value set in advance so as to achieve a taste balance according to the user's preference.

  When the crystallization of the salt is completed in this way, the crystallized salt is recovered by performing solid-liquid separation such as discharging the residual liquid, filtering, or centrifuging (step S20).

The oven, the water content of the recovered salt by performing heating or drying operation of the ventilation or the like, after dried until approximately 5% by weight (step S21), and performs sieving, diameter 1mm or less and The crystal salt (product) having such a particle size is collected (step S22).

Since the mineral in the secondary concentrated liquid is precipitated on the surface of the sodium chloride crystal, if the crystallized crystal has a relatively small particle size, the surface area per unit mass of the crystal is relatively large. The proportion of mineral contained per unit mass of is relatively high. In the salt having a particle diameter of 1 mm or less in diameter, the surface area per unit mass of the crystal is sufficiently wide, and the ratio of mineral precipitation is high. Moreover, in the salt of the particle size of below 1mm in diameter as will be described later, there is a high rate of deposited mineral components a sweetness such calcium sulfate and magnesium chloride, sweetness increased, improved taste exhibiting salt Can be obtained.

  On the other hand, as described above, a salt of a crystal having a small particle diameter such as a diameter of 1 mm or less can be produced with high efficiency by the salt production method described above.

Therefore, in the present salt production method, a salt (product) having a high mineral content and a taste with an increased sweetness can be efficiently produced.

  Such a salt is preferred because it has a relatively stronger sweetness than conventional sun-made salt, so that it is suitable for use in meat dishes such as fried meat, steak, stew and the like.

  In the present embodiment, the concentration tank used for primary concentration and the salt crystallization tank used for secondary concentration are configured in different containers, but the present invention is not limited to this, and for salt crystallization. You may make it the structure which also performs primary concentration using a tank. As a result, the salt production facility can be simplified and the facility cost can be reduced.

On the other hand, when the concentration tank used for primary concentration and the salt crystallization tank used for secondary concentration are configured in different containers, there is a risk that calcium sulfate may adhere to the inner surface having the surface roughness of the salt crystallization tank. Since there is almost no need to remove calcium sulfate, the life of the salt crystallization tank can be extended.

By the way, although the crystals other than the crystal having the particle size sorted in step S22 contain the same mineral as the conventional sun salt, the sweetness is relatively weak as compared with the salt sorted as described above. Although the saltiness is relatively strong, for example, when used in vegetable dishes such as vegetable salads and stewed vegetables, the taste matches well, so it can be used in various dishes without being discarded.

(Second Embodiment)
FIG.2 and FIG.3 is a flowchart which shows the procedure of the salt production based on 2nd Embodiment, and a particle size is relatively small by adjusting the depth of the brine in the salt crystallization tank of secondary concentration. The crystal crystallization rate is increased.

As shown in FIG. 2, raw water is prepared by performing the same operation as that described in step S1 of FIG. 1 (step S31). The raw water is stored in a concentration tank (step S32), and the primary concentration in which water is evaporated from the raw water by heating the raw water in the evaporation tank with sunlight or a heater is started (step S33). specific gravity to implement primary concentrated to determined to have reached the value from 1.12 to 1.22 (step S34). When the specific gravity reaches the value from 1.12 to 1.22 , the primary concentration is finished (step S35), and the crystallized calcium sulfate (CaSO ₄ ) and the primary concentrated solution are separated (step S36). ).

  Next, storage of the primary concentrated liquid obtained by separation into the salt crystallization tank is started (step S40). When it is determined that the depth of the primary concentrate has reached a predetermined ratio with respect to the depth dimension of the salt crystallization tank (step S41), the primary concentrate is stored, and when the predetermined ratio has been reached, The storage of the primary concentrate is terminated (step S42).

Secondary concentration in which the primary concentrated liquid in the evaporation tank is heated to a temperature of less than 60 ° C. by sunlight or a heater to evaporate water from the primary concentrated liquid (step S43), and the specific gravity of the secondary concentrated liquid is 1. The secondary concentration is performed until it is determined that the value from 24 to 1.29 has been reached (step S44). Then, when it reaches the specific gravity of this, it ends the secondary concentrate (step S45).

Here, the salt crystallization tank may be used even if the inner surface is flat as long as it has a depth of 19% or more and 50% or less of the depth dimension of the salt crystallization tank. it can.

The depth of the salt crystallization tank can be about 2 cm to about 10 cm. When the depth of the salt crystallization tank is shallower than about 2 cm, before the secondary concentration is completed, the crystals extend to the upper edge of the salt crystallization tank and extend to the inner surface of the salt crystallization tank. Due to the capillary action of crystals, the primary concentrated liquid stored in the salt crystallization tank leaks out of the salt crystallization tank. Also, when the depth of the salt crystallization tank is deeper than about 10 cm, it takes a long time for the secondary concentration, and there is a disadvantage that a salt crystal having a diameter of 1 mm or less cannot be obtained. is there.

  On the other hand, in the case of using a salt crystallization tank having an average surface roughness of 0.1 μm or more and 0.4 μm or less in the contact region of the secondary concentrated liquid as before, this average surface roughness is as described above. Since an effect also arises, it is preferable.

  The primary concentrated liquid is stored in the salt crystallization tank so as to have a depth of 19% or more and 50% or less of the depth dimension of the salt crystallization tank, and then secondary concentration is started to crystallize the salt. Analyze.

  Thus, by setting the amount of primary concentrated liquid introduced to 19% to 50% of the depth dimension of the salt crystallization tank, the crystallized salt has a relatively small particle diameter of 1 mm or less. The crystal content increases.

This is because as the depth of the primary concentrated liquid stored in the salt crystallization tank becomes deeper, the crystallization speed becomes slower, and thereby the crystal grain size to be crystallized becomes gradually smaller. Thus, primary concentration solution stored in ShioAkira析用tank, is greater than or equal to 19% of the depth of ShioAkira析用tank, increasing the content of the crystal particle size diameter is say 1mm or less It can be done.

  On the other hand, when the introduction amount of the primary concentrated liquid exceeds 50% of the depth dimension of the salt crystallization tank, the crystal of the crystallized salt is removed from the upper edge of the salt crystallization tank before the secondary concentration is completed. In this case, the secondary concentrated liquid leaks out of the salt crystallization tank due to the capillary action of the extended crystals.

As described above, when the specific gravity of the secondary concentrated liquid reaches a value from 1.24 to 1.29, after the secondary concentration is finished, solid-liquid separation such as discharge of residual liquid, filtration or centrifugation is performed. The crystallized salt is recovered (step S50).

The oven, after the salt recovered by carrying out the drying operation such as heating or ventilation by the heater and dried (step S51), salts of performing sieving, for example a particle size diameter of said 1mm or less crystalline (Product) is collected (step S52).

As a result, the salt with a high mineral content and improved taste can be efficiently produced as before.

Example 1
The result of having verified about the granular salt of this invention is demonstrated.

  According to the above embodiment, the granular salt of the present invention is heated from 20 ° C. to 60 ° C., preferably from 20 ° C. to 45 ° C. in the evaporation tank by the sun or a heater in the above step S11. Secondary concentration to evaporate the water is started, and it is crystallized by maintaining the temperature at 20 ° C. to 60 ° C., preferably 20 ° C. to 45 ° C. in the secondary concentration. FIG. 4 is an experimental result showing the relationship between the crystallization temperature and the yield.

  As shown in FIG. 4, the Nos. 1, 2, and 3 that are crystallized at a temperature higher than 45 ° C. have an SS size granular salt yield of about 30% at most, but are crystallized at 45 ° C. or lower. In Nos. 4, 5, and 6, the yield of SS-size granular salt is higher than 30%. Nos. 1 to 6 in the figure are results when a polystyrene container is used as a salt crystallization tank, but the same result is obtained even when a straw container or a hard aluminum container is used. can get. The example of the result when using a container made of firewood or a container made of hard aluminum is shown by item number 6 (琺 瑯) and item number 6 (aluminum) in the figure. These obtained the result that the yield of the granular salt of SS size was higher than the container made from polystyrene.

  In addition, an energy dispersive X-ray fluorescence analyzer (Rayny EDX- manufactured by Shimadzu Corporation) is used for M size, S size, SS size and commercially available (M size) granular salt produced by the salt production method of the present invention. 800HS), mineral components present on the crystal surface of the granular salt were confirmed.

  The granular salt of the present invention is composed of particles (S size and SS size) having a particle size of 0.25 mm to 2 mm. FIG. 5 is a verification result of mineral elements contained in the granular salt of the present invention. As shown in FIG. 5, the mineral content of calcium, magnesium, potassium and sulfur was 4.039% by mass and 5.802% by mass, respectively, with respect to the total crystal weight of the granular salt.

  Further, as shown in the figure, the granular salt composed of particles (M size) having a particle size larger than 2 mm contains 3.269% by mass of this mineral content with respect to the total crystal weight of the granular salt. It was. Further, as shown in the figure, the commercial product (M size) granular salt contained 1.867% by mass of this mineral content with respect to the total crystal weight of the granular salt.

  Thus, the granular salt of the present invention is rich in mineral content compared to other granular salts, so the multiple mineral content contains various tastes, and a rich nourishment. Can bring.

  The granular salt of the present invention contains calcium, magnesium, potassium and sulfur in an amount of 4% by mass to 22% by mass with respect to the total crystal weight of the granular salt. When calcium, magnesium, potassium and sulfur are 4 mass% or less of the granular salt based on the total weight of the crystalline crystals of the granular salt, the granular salt composed of particles (M size) having a particle size larger than 2 mm in FIG. And since the mineral content is small like the granular salt of a commercial item (M size), the deep taste by a mineral content is not obtained. Further, when calcium, magnesium, potassium and sulfur are 22 mass% or more of the granular salt based on the total crystal weight of the granular salt, sodium chloride in the seawater is 78 mass%. In addition to being unable to be carried out by the law, the sodium salt is too small, so that the original salty taste exhibited by sodium chloride is lost.

  From the viewpoint of the original salty taste exhibited by this sodium chloride, sodium is preferably 55% by mass or more with respect to the total crystal weight of the granular salt. As an example in which sodium is smaller than 55% by mass with respect to the total weight of crystals of the granular salt, a granular salt (sodium content is 54.997) composed of particles (M size) having a particle size of 2 mm or more shown in FIG. Mass%) and the sodium content is too small, so that the original salty taste of sodium chloride is lost.

  Furthermore, the granular salt of the present invention preferably contains 4 mass% or more and 6 mass% or less of calcium, magnesium, potassium, and sulfur with respect to the total crystal weight of the granular salt. The granular salt in this case is an S size and SS size granular salt shown in FIG. 5, and since the contained mineral balance is appropriate, the plural minerals contained mutually enhance various tastes, Furthermore, it can bring a rich taste.

  Moreover, although all the types of calcium, magnesium, potassium, and sulfur were contained as a mineral content in the above, at least 1 type may be contained as a mineral content among calcium, magnesium, potassium, and sulfur. When there are few kinds to contain, there exists an advantage that the taste characteristic for each mineral tends to appear in a granular salt.

  FIG. 6 is an electron microscope SEM (Scanning Electron Microscope) photograph taken with JXA-8800R, an electron probe microanalyzer of the surface and fracture surface of the salt particles. From the figure, it can be seen that the SS-sized granular salt of the present invention has a finer amount of minerals adhering to its surface than the commercially available product (M-sized) and the M-sized granular salt. Further, it can be seen from the SS size fracture surface of the present invention that the inside of the fracture surface is smooth and fine mineral particles are not seen. As described above, since a large amount of fine mineral particles are adhered to the surface of the salt particles, a taste effect due to the presence of the fine mineral particles can be effectively obtained.

  7 and 8 are an SEM photograph (SL) and surface analysis in the same field of view by the electron probe microanalyzer JXA-8800R in the surface, fracture surface, and radial direction of the salt particles. From this surface analysis, the X-ray detection intensity of each mineral element (sodium (Na), chlorine (Cl), magnesium (Mg), calcium (Ca), sulfur (S), potassium (K)) It can be seen that the SS size surface increases, and the fine SS size surface is attached in a larger amount.

  Further, FIG. 9 shows an SEM image (SL) from the interface generated by the fracture of the SS-sized granular salt by an electronic probe microanalyzer JXA-8800R, and each mineral element (sodium (Na ), Chlorine (Cl), Magnesium (Mg), Calcium (Ca), Sulfur (S), Potassium (K) surface analysis and line analysis.From this surface analysis and line analysis, each mineral content (magnesium: Mg , Calcium: Ca, sulfur: S, potassium: K) are crystallized as various mineral salts of fine particles on the surface of the granular salt.

Further, an X-ray diffraction diagram of the granular salt (crystal grains) obtained by crystallization is shown in FIG. From this X-ray diffraction diagram, diffraction lines corresponding to NaCl and CaSO ₄ 2H ₂ O can be confirmed. The peak intensity of the diffraction line corresponding to CaSO ₄ 2H ₂ O increases as the crystal grain size decreases. This result suggests that the smaller the crystal grains, the more CaSO ₄ 2H ₂ O is contained.

FIG. 10B shows an X-ray diffraction pattern of seawater component crystals that crystallize on the surface of the salt particles during the drying process after salt collection. This figure shows an X-ray diffraction pattern of seawater component crystals that crystallize on the surface of salt particles during the drying process after salt collection. Sodium chloride (NaCl), magnesium sulfate (MgSO ₄ ), and magnesium chloride (MgCl _2). ) Peak is also shown . The mineral component present on the salt surface after salt collection increases in salinity as the water evaporates due to drying , and magnesium sulfate (MgSO) accompanies the transition from (A) to (B) (C) in the figure. ₄ ) was confirmed to appear. Further, it was confirmed that magnesium chloride (MgCl ₂ ) appeared with the transition to (D) in the figure . From this, it is thought that crystallization of magnesium sulfate and magnesium chloride occurs in this order.
From the experimental results of each surface analysis, it was confirmed that calcium sulfate and these crystallized salts were crystallized as particles on the surface of the salt particles. Thus, calcium (Ca), magnesium (Mg), potassium (K) and sulfur (S), which are mineral components contained in the granular salt of the present invention, are magnesium sulfate (MgSO ₄ ), calcium sulfate (CaSO ₄ ). ), Magnesium chloride (MgCl ₂ ), calcium chloride (CaCl ₂ ), potassium chloride (KCl), and the like.

(Example 2)
The results of comparative tests on the salt crystallization tank will be described.

  FIG. 11 shows the results of secondary concentration using a salt crystallization tank that has been subjected to brazing treatment and a salt crystallization tank that has not been subjected to brazing treatment. It is a histogram which shows the measurement result, and the vertical axis shows the yield and the horizontal axis shows the crystal grain size. In the figure, (a) shows the results using the salt crystallization tank subjected to the brazing treatment, and (b) shows the results using the salt crystallization tank not subjected to the brazing treatment. ing.

  A commercially available container made of polystyrene resin (Vat A78, manufactured by Daiso Sangyo Co., Ltd.) was used for the salt crystallization tank. In addition, the dimension of a container is 23 cm in length, 31.6 cm in width, and 4.3 cm in height.

  The brazing treatment takes about 5 g of powdered calcium sulfate having an average particle diameter of about 2 mm, puts it into the container, and uses the cloth for 5 minutes on the inner surface of the container. Done by rubbing. Thereafter, the inside of the container was washed to remove the powder, and the container was dried and used for the test.

1000 ml of the primary concentrated liquid having a specific gravity of 1.22 is stored in each of the salt crystallization tanks and subjected to secondary concentration until the specific gravity reaches 1.27 by the sun below 60 ° C., and then solid-liquid separation. To obtain a salt which was dried until the water content was 2.5% by weight. The specific gravity was measured using a salt water seed meter (200 mm JAN 702007, manufactured by Ishihara Thermometer Co., Ltd.).

  Then, the dried salt was sieved into M size with a diameter exceeding 2 mm, S size with a diameter exceeding 1 mm and 2 mm or less, and SS size with a diameter of 1 mm or less, and the yield of each size was measured.

  As a result, as is apparent from FIG. 11, in the M size, the yield was higher when the salt crystallization tank not subjected to the brazing treatment was used. The yield was higher when the salt crystallization tank was used.

  Furthermore, in the SS size, which is the size of the salt according to the present invention, when a salt crystallization tank subjected to brazing was used, there was a yield of about 12% by mass. In the case of using a salt crystallization tank that had not been subjected to an attaching treatment, the yield was only about 2% by mass, and there was a 6-fold difference between the two yields.

  As described above, SS-sized granular salt could be obtained with high efficiency by using the salt crystallization tank subjected to the brazing treatment.

(Example 3)
Next, the result of examining the relationship between the surface roughness and material of the salt crystallization tank and the size of the crystal of the salt crystallized will be described.

  FIG. 12 is a graph showing the results of measuring the average surface roughness of various salt crystallization tanks, in which (a) is a container made of polystyrene described in Example 1 and brazed. (B) is a container made of polystyrene described in Example 1 and subjected to brazing treatment, (c) is a container made of hard aluminum, and (d) is stainless steel. (E) has shown the container of Arita ware.

  In addition, the container made from hard aluminum uses Akao aluminum bud No. 4, and the container made from stainless steel uses SUS304 * 18-8.

  The average surface roughness was measured according to JISB-0601 (1994) using a surface roughness measuring device (Surfcom LC-3424, Tokyo Seimitsu Co., Ltd.).

  As apparent from FIG. 12, the average surface roughness of the container (a) not subjected to the brazing treatment was 0.069 μm, whereas the average surface of the container (b) subjected to the brazing treatment was The roughness was 0.251 μm. The average surface roughness of the hard aluminum container was 0.386 μm, the average surface roughness of the stainless steel container was 0.135 μm, and the average surface roughness of the Arita ware container was 0.304 μm. .

  The operations similar to those described in Example 2 were performed using each of these containers, and the obtained salts were sieved to determine the yields of crystals of each size. (B) to (e) In any case, the yield of SS-size crystals was increased as compared to the case where the container (a) was used.

These results and more inventors experience, the effect of increasing the content of the crystal particle size diameter is say 1mm or less, the container average surface roughness of at least 0.1μm than 0.4μm or less The knowledge that it is obtained by using was obtained.

Example 4
Next, the result of having tested about the influence of the depth of the primary concentrated liquid stored in the salt crystallization tank is demonstrated.

  FIG. 13 is a histogram showing the results of measuring the yield of each crystallized crystal according to the particle size by performing secondary concentration by changing the depth of the primary concentrated solution stored in the salt crystallization tank. In the figure, the vertical axis represents the yield, and the horizontal axis represents the crystal grain size. (A) shows the result when 350 ml of the primary concentrate was stored, and (b) shows the primary concentrate. The results when 500 ml is stored, (c) shows the results when 750 ml of the primary concentrate is stored, and (d) shows the results when 1000 ml of the primary concentrate is stored.

  The salt crystallization tank was made of the same material as the container described in Example 2 and had the same dimensions, but the inner surface was not brazed.

In each of the four salt crystallization tanks, 350 ml (a), 500 ml (b), 750 ml (c), and 1000 ml (d) of a primary concentrated liquid having a specific gravity of 1.20 were stored. Therefore, the depths of the primary concentrate stored in each salt crystallization tank are 0.48 cm (a), 0.69 cm (b), 1.03 cm (c), and 1.38 cm (d), respectively. . Since the depth of the salt crystallization tank is 4.3 cm as described above, the ratio of the depth of the stored primary concentrate to the depth of the salt crystallization tank is 11.2% (a ), 16.0% (b), 24.0% (c), and 32.1% (d).

In each salt crystallization tank, secondary concentration was performed until the specific gravity reached 1.27 under the temperature condition of 53 ° C. by the sun, and then solid-liquid separation was performed to obtain a salt with a water content of 2 mass. % Until dry. Then, the dried salt was sieved into M size with a diameter exceeding 2 mm, S size with a diameter exceeding 1 mm and 2 mm or less, and SS size with a diameter of 1 mm or less, and the yield of each size was measured.

  As a result, as apparent from FIG. 13, in the SS size, the ratio of the depth of the stored primary concentrated liquid to the depth dimension of the salt crystallization tank is larger than 24.0% (c). When the ratio of the depth of the stored primary concentrate to the depth dimension of the salt crystallization tank is smaller than 16.0% (b) The yield was only about 12% by mass.

  Although not shown in FIG. 13, the ratio of the depth of the stored primary concentrate to the depth of the salt crystallization tank is 19.0% (corresponding to 600 ml under the same conditions as in this example). ) Above this level, the effect of increasing the SS size yield was obtained.

  From the above, by setting the ratio of the depth of the primary concentrated solution stored in the salt crystallization tank to the depth of the salt crystallization tank to 19.0% or more, the SS size salt is made highly efficient. Can get to.

(Example 5)
Next, the result of having measured the content rate of the component element about the salt obtained in Example 2 is demonstrated.

  14 shows the contents of a plurality of component elements constituting the SS-size salt according to the present invention obtained in Example 2, and a plurality of components constituting other-size salts screened in Example 2. FIG. It is a graph which shows the result of having measured the content rate of an element, and the vertical axis | shaft has shown the content rate and the horizontal axis has each shown the size of the screened salt. Further, in the figure, the square mark indicates Mg, the triangle mark indicates Ca, the diamond mark indicates Na, and the circle indicates K. In addition, content of Na is shown by the value of 1/100, and the actual content rate is the value which multiplied the numerical value of the graph 100 times.

  The content of each component element was measured using an energy dispersive X-ray fluorescence analyzer (Rayny EDX800HS, Shimadzu Corporation).

  As is clear from FIG. 14, the SS-size salt according to the present invention has 1.3 times the Mg and Ca contents as compared to the S-size and M-size salts having larger particle sizes. More than 3 times more.

In Mg and Ca, respectively, magnesium chloride and calcium sulfate are formed to exhibit sweetness. Therefore, in the SS size salt according to the present invention, the presenting taste can be improved .

(Example 6)
Next, the results of sensory tests on the salt of the size according to the present invention and the salt of other sizes will be described.

  The sensory test was performed as follows.

  As a sample subjected to the sensory test, the SS size salt shown in Example 2 was used as an example of the present invention, and the M size salt shown in Example 2 was used as a comparative example. And the salt of both sizes was grind | pulverized using the mortar, respectively, and it was set as the sample which mutually equalized the particle size by fractionating the salt with a particle size of 0.25 mm or more and 1 mm or less with a sieve.

  A woman who is 22 years old, 12 subjects are subjects, and each subject puts both samples separately into small dishes, and the color, aroma, salty taste, sweetness, bitterness and umami that each sample exhibits are from -3 A comparative study was conducted by a two-point discrimination / preference test method using a seven-level scale up to +3. The obtained examination data was statistically processed by t-test.

  FIG. 15 is a graph showing the results of comparative examination of the sample of the present invention and the sample of the comparative example by the two-point identification / preference test method. In the figure, when one asterisk mark is attached, the risk rate is less than 1%, and when two asterisk marks are attached, the risk rate is less than 5%. In all cases, it was judged to be significant.

As is clear from FIG. 15, the sample of the present invention was significantly weaker in saltiness, significantly stronger in sweetness, and significantly weaker in bitterness than the sample in the comparative example. That, in the sample of the present invention embodiment is a mild 0.00-called flaps, bitterness (acridity) had no meaning is obtained.

(Example 7)
Next, the result of having measured the content rate of the several component element which comprises the salt manufactured using the primary concentrated liquid of different specific gravity is demonstrated .

FIG. 16 shows the contents of a plurality of component elements constituting the SS-size salt according to the present invention obtained by using a primary concentrate having a specific gravity of 1.17, and sifted in the production process. It is a graph which shows the result of having measured the content rate of the some component element which comprises the salt of another size, FIG. 17 is the present invention obtained by manufacturing using the primary concentrated liquid whose specific gravity is 1.22. It is a graph which shows the result of having measured the content rate of the several component element which comprises the salt of SS size which concerns on, and the content rate of the several component element which comprises the salt of the other size screened in the manufacturing process. is there. In both figures, the vertical axis represents the content and the horizontal axis represents the size of the screened salt. Further, in the figure, the square mark indicates Mg, the triangle mark indicates Ca, the diamond mark indicates Na, and the circle indicates K. In addition, content of Na is shown by the value of 1/100, and the actual content rate is the value which multiplied the numerical value of the graph 100 times.

The secondary concentration is stopped when both reach the same specific gravity . On the other hand, although the same material as the container described in Example 2 and the same size were used for the salt crystallization tank, the inner surface was not brazed.

As apparent from FIGS. 16 and 17, the Ca content is in any size including the salt of the SS size according to the present invention when the primary concentrated liquid having a specific gravity of 1.17 is used. Compared with the primary concentrated liquid having a specific gravity of 1.22, it was lower.

This is because the amount of crystallization of calcium sulfate increases as the specific gravity at which primary concentration is stopped is set higher, so that the specific gravity is 1.22 primary than the concentration of Ca contained in the primary concentrated liquid of 1.17. This is probably because the concentration of Ca contained in the concentrate is lower.

On the other hand, the content of Mg is, in any size, including a salt of SS size according to the present invention, primary concentration of specific gravity as compared with the case where the specific gravity is used primarily concentrated liquid of 1.17 1.22 It was higher when the liquid was used.

In addition, in the SS size salt according to the present invention, when the primary concentrated liquid having a specific gravity of 1.17 is used and when the primary concentrated liquid having a specific gravity of 1.22 is used, The balance with the Mg content was different.

Here, as described above, Ca and Mg constitute magnesium chloride and calcium sulfate, respectively, and calcium sulfate has a sweet taste and magnesium chloride has a light taste.
As mentioned above, the taste of the salt obtained can be adjusted by using the primary concentrate of different specific gravity .

Claims (2)

A primary concentrated liquid obtained by heating raw water from seawater as a primary concentrate to a specific gravity of not less than 1.12 and not more than 1.22 is stored in a salt crystallization tank and heated. A salt production method in which a granular salt is crystallized by secondary concentration to a specific gravity of 24 to 1.29, and the inner surface has an average surface roughness of 0.1 μm or more and 0.4 μm or less in a salt crystallization tank. The primary concentrated solution is stored and then subjected to secondary concentration, or / and the salt crystallization tank has a concentration of 19% to 50% of the depth of the salt crystallization tank. To store the secondary concentration,
A method for producing a salt, wherein a salt of a crystal having a diameter of 1 mm or less is fractionated from a salt obtained by secondary concentration.   The salt production method according to claim 1, wherein the salt of the crystal having a particle diameter of 1 mm or less is fractionated by sieving.