Methods for producing concentrated products using pulp concentration and freeze-drying concentration.

Abstract

Updated 28 / 04 / 2016 A method for producing concentrated products using membrane concentration. (membrane-concentration method) and freeze-concentration method. A method that helps reduce the process time (concentration time) required in production. In large quantities (commercial level), efficiently (practically) using methods. Membrane concentration and freeze-drying concentration methods are combined: the concentration steps... Membrane concentration is used in a method where the fluid to be concentrated is cooled and the fluid being concentrated is cooled. The membrane is prepared by membrane concentration until the solid content of this fluid is reduced. It is 1.5 times more concentrated; the ice crystallization process where the fluid is concentrated. The membrane-based system was cooled, and the ice crystals of the concentrated fluid were removed. This occurs in the membrane-concentrated fluid and creates a fluid mixture that will... It becomes concentrated because the fluid mixture that is being concentrated contains the aforementioned ice crystals. And the concentrated fluid that will be further concentrated is produced from the fluid concentrated using such a membrane. By inducing the formation of ice crystals in the fluid during membrane concentration, the fluid is thus concentrated. Concentration using the membrane; and the ice crystal separation process where the fluid is mixed. This was separated into a concentrated fluid that would be further concentrated and ice crystals. This results in the recovery of a concentrated fluid that can be further concentrated after the separation process. --------------------------------------------------------------------------- A method for producing concentrated products using membrane concentration. (membrane-concentration method) and freeze-concentration method. A method that helps reduce the process time (concentration time) required in production. In large quantities (commercial level), efficiently (practically) using methods. Membrane concentration and freeze-drying concentration methods are combined: the concentration steps... Membrane concentration is used in a method where the fluid to be concentrated is cooled and the fluid being concentrated is cooled. The membrane was prepared by membrane concentration until the solid content of this fluid was reduced. More than 1.5 times concentrated; an ice crystallization process using membrane-concentrated fluid. As the fluid is cooled, ice crystals are formed from the concentrated fluid using the membrane technique. In such membrane-concentrated fluids, a fluid mixture is formed that is then further concentrated by... The fluid mixture that is being concentrated contains the aforementioned ice crystals and the fluid. The concentrate is further concentrated by producing a fluid that is concentrated using a membrane by causing... Ice crystals form in the fluid when concentrated using this membrane, thus concentrating the fluid. The membrane-based method is intensified; and the ice crystal separation process involves separating the fluid mixture. It is released as a concentrated fluid that will be further concentrated and as ice crystals, thus obtaining the following: The concentrated flow that is further concentrated after the separation process is recovered;

Description

This invention relates to a method for producing concentrated products using membrane concentration technology and freeze concentration technology. In the freeze-concentration method, the processing liquid (fluid to be processed) is not excessively heated during concentration, so the concentrated liquid can be prepared without any changes in flavor (such as heated odor) caused by heating or warming. In freeze concentration methods, two types are known: suspension crystallization (suspension crystal concentration), which generates granular ice crystals in a crystallization tank, and interfacial advance freeze concentration, which grows ice crystals on a cooling surface. Considering factors such as the ease of solid-liquid separation between ice (water) and the concentrate, interfacial advance freeze concentration is generally the most commonly used freeze concentration method. For example, Patent Document 1, which is Patent No. 4306018, proposes a scraping heat transfer freeze concentration method and its apparatus as a freeze concentration apparatus. Also, Patent Document 2, which is Patent No. 4429665, proposes a forward freeze concentration method and its apparatus as a freeze concentration apparatus. Furthermore, for liquid foods, particularly fruit juices, coffees, and teas, freeze-concentration methods have been proposed that can suppress the deterioration of the quality of the concentrated liquid. For example, Patent Document 3 describes how the deterioration of the quality of concentrated liquids such as fruit juices can be prevented by using a combination of an interfacial advance freeze-concentration method and deoxygenation treatment, and also states that this technology can be used for milk. Furthermore, in the suspension crystal concentration method, Patent Document 4 proposes a method in which seed crystals of a predetermined size are formed in each of the multiple steps, these seed crystals are transferred to a recrystallization container containing a less concentrated solution, and the generated seed crystals are then transferred to a recrystallization container containing a less concentrated solution, thereby enabling efficient concentration by the suspension crystal concentration method. Japanese Patent Publication No. 2000-334203, Japanese Patent Publication No. 2005-81215, Japanese Patent Publication No. 2006-166880, Japanese Patent Publication No. 57-105202 According to the freeze concentration method, since the processing liquid is not excessively heated during concentration, a concentrated liquid can be prepared without accompanying flavor changes (such as heating odor) due to heating or warming. In addition, it is possible to suppress the growth of microorganisms in the concentrated liquid caused by heating or warming, and suppress risks such as deterioration of the concentrated liquid by microorganisms and contamination of the concentrated liquid by microorganisms. Therefore, in the freeze concentration method, it is considered suitable for concentrating liquid raw materials with a large number of microorganisms (for example, milk materials such as raw milk before sterilization). However, conventionally, when concentrating milk materials (for example, raw milk, skim milk, fermented milk (liquid fermented milk, drinkable yogurt, etc.), lactic acid bacteria beverages, whey, buttermilk, and concentrated liquids thereof (membrane concentrated liquids, etc.)), it has been difficult to adopt a method for preparing a concentrated liquid by the freeze concentration method. This is one of the reasons for the large losses that occur when the freeze concentration method is adopted for concentrating milk materials. For example, conventionally, when a known freeze concentration method (for example, the front advancing freeze concentration method) is adopted and the solid content concentration (solid content) of milk materials such as raw milk before sterilization is concentrated up to twice the solid content concentration (solid content) before concentration, when it is large, in terms of the solid content amount, about 2% by weight of the whole is lost without being retained in the concentrated liquid. When concentrating a large amount of milk materials, such as in the large-scale (commercial scale) production of dairy products, the high loss rate results in unintended waste, which has been a major obstacle to adopting the freeze concentration method for concentrating milk materials. Thus, conventionally, it has been difficult to adopt the freeze concentration method for concentrating milk materials in practical use due to poor economic production efficiency. And if the multi-stage countercurrent concentration method of Patent Document 4 is adopted, it is necessary to use a plurality of freeze concentration devices simultaneously, etc., and it has not been easy to obtain satisfactory efficiency. From such a perspective, conventionally, for concentrating milk materials, a vacuum heating concentration method or a membrane concentration method (for example, reverse osmosis membrane: RO membrane, nanofiltration membrane: NF membrane), etc. has been adopted alone or in combination. Here, the vacuum heating concentration method is a concentration method in which moisture is evaporated from the processing liquid in a state where the milk material is heated to about 40°C to 80°C in an atmosphere depressurized by a vacuum pump or the like. However, in this vacuum heating concentration method, it is known that microorganisms proliferate in the concentrated liquid within a few days of starting the concentration of raw milk and other dairy materials before sterilization, and the degree of this proliferation is reflected in the number of microorganisms actually present in the prepared concentrated liquid. On the other hand, in order to reduce this number of microorganisms, it is assumed that the dairy materials concentrated by the vacuum heating concentration method will be heat-sterilized. Because the concentrated liquid of these dairy materials has a high concentration of solids derived from milk components, these milk components may burn onto the heat transfer surfaces and nozzles of the heat sterilizer (plate sterilizer, tube sterilizer, injection sterilizer, infusion sterilizer, scrape sterilizer, etc.), or their physical properties and quality may change significantly (for example, viscosity may increase, or aggregates may form). Therefore, it has been difficult or impossible to reduce the number of microorganisms by sterilizing this concentrated dairy material for a long period of time. The membrane concentration method involves cooling the milk material (to 5-10°C, etc.) and using a separation membrane such as a reverse osmosis membrane to pressurize the processed liquid with a pressure pump or the like to remove water and concentrate the liquid. However, this membrane concentration method is known to have a low limit to the concentration at which the processed liquid can be concentrated. For example, in a simple membrane concentration process, it was difficult or impossible to increase the solid content concentration of milk materials, such as raw milk before pasteurization, to about 30-40% by weight. Therefore, the present invention aims to provide an efficient method for producing concentrated products using (or in combination with) a membrane concentration method and a freeze concentration method that have a high recovery rate (low loss rate) and are practical for large-scale (commercial-scale) production. Through diligent research, the inventors of this invention have discovered that by combining the concentration of the fluid to be treated by a membrane concentration method (reverse osmosis membrane method: RO membrane method, nanofiltration membrane method: NF membrane method, ultrafiltration membrane method: UF membrane method, microfiltration membrane method: MF membrane method, etc.), the concentration of the membrane-concentrated fluid by suspension crystallization (or suspension crystallization method), and the separation and discharge of the ice crystals generated by the suspension crystallization method, and performing this process continuously, the processing time (concentration time), when converted to a unit volume (unit weight) of the fluid to be treated, can be efficiently shortened compared to the conventional freeze concentration method. Furthermore, we discovered that by cooling the temperature of the fluid to be treated and the treated concentrated fluid to 0-20°C during the membrane concentration method, the fluid to be treated and the treated concentrated fluid are not heated excessively. As a result, it is possible to commercially produce freeze-concentrated products (freeze-concentrated foods) that can be stored stably for a long period of time while maintaining the original flavor derived from the fluid (dairy ingredients, etc.). In this case, when using dairy material as the fluid to be processed, for example, when increasing the solid content concentration from approximately 12% by weight to approximately 30% by weight (concentrating), the concentrated product (membrane-concentrated / freeze-concentrated dairy food) obtained based on the present invention could reduce the processing time (concentration time) by up to 70% compared to conventional concentrated products (freeze-concentrated dairy food produced by conventionally known freeze-concentration methods). Specifically, when using 100 kg of dairy material as the fluid to be processed, the processing time for preparing (manufacturing) a conventional concentrated product using a conventionally known freeze-concentration method to concentrate the solid content from approximately 12% by weight to approximately 30% by weight was approximately 40 hours, while the processing time for preparing the concentrated product obtained based on the present invention was approximately 30 hours. In large-scale (commercial-scale) dairy product manufacturing, where large quantities of dairy materials are concentrated, the long processing time from the start of the process to the recovery of the concentrated product has been a major obstacle to adopting freeze-concentration for concentrating dairy materials. Thus, conventionally, it has been difficult to quickly produce concentrated products in response to supply and demand, making it impractical to adopt freeze-concentration for concentrating dairy materials. The invention described in claim 1 of the present invention is a membrane concentration method and a method for producing a concentrated product by freeze concentration, comprising: a membrane concentration step of cooling a fluid to be treated and membrane-concentrating the solid content concentration to 1.5 times or more using one of a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, or a microfiltration membrane to prepare (produce) a membrane-concentrated fluid to be treated; an ice crystal generation step of cooling the membrane-concentrated fluid to be treated, causing ice crystals to form in the membrane-concentrated fluid to be treated, and mixing the concentrated fluid to be treated, which is further concentrated by the formation of the ice crystals, with the ice crystals; and an ice crystal separation step of separating the mixed fluid into the concentrated fluid to be treated and the ice crystals, and extracting the concentrated fluid to be treated. The invention described in claim 2 is a method for producing a concentrated product by the freeze concentration method described in claim 1, characterized in that the following steps are performed in a batch manner: preparing the membrane-concentrated fluid to be treated; making a mixed fluid of the membrane-concentrated fluid to be treated, which is a further concentrated fluid to be treated, and the ice crystals; and separating the mixed fluid into the concentrated fluid to be treated and the ice crystals to extract the concentrated fluid to be treated. The invention described in claim 3 is a method for producing a concentrated product by the membrane concentration method and the freeze concentration method according to claim 1 or 2, characterized in that the ice crystal generation step and the subsequent ice crystal separation step are repeated once or more times with respect to the concentrated fluid to be treated taken out in the ice crystal separation step. The invention described in claim 4 is a method for producing a concentrated product by the membrane concentration method and freeze concentration method described in claim 3, characterized in that, in the second and subsequent ice crystal generation steps, the membrane concentration fluid to be treated in a volume corresponding to the ice crystals separated in the preceding ice crystal separation step is added to the concentrated fluid to be treated taken out in the preceding ice crystal separation step to create a new fluid to be concentrated, and the second and subsequent ice crystal generation steps are performed. The invention described in claim 5 is a method for producing a concentrated product by a membrane concentration method and a freeze concentration method according to any one of claims 1 to 4, characterized in that the fluid to be processed is any of raw milk, skim milk, fermented milk (liquid fermented milk, drinkable yogurt, etc.), lactic acid bacteria beverage, whey, or buttermilk. The invention described in claim 6 is a method for producing a concentrated product by the membrane concentration method and freeze concentration method described in any one of claims 1 to 5, characterized in that the aroma components are retained at a level of 0.7 times or more compared to an untreated product. The invention described in claim 7 is a method for producing a concentrated product by the membrane concentration method and the freeze concentration method according to any one of claims 1 to 6, characterized in that the number of viable beneficial microorganisms is maintained at 0.7 times or more compared to an untreated product. According to the present invention, it is possible to provide an efficient method for producing concentrated products using (or in combination with) membrane concentration methods and freeze concentration methods that have a high recovery rate (low loss rate) and are practical for use in large-scale (commercial-scale) manufacturing. According to the present invention, the processing time (concentration time), when converted to a unit volume (unit weight) of the fluid to be processed, can be efficiently shortened compared to the conventional freeze concentration method. According to the present invention, the waste loss rate, calculated in terms of solid content, can be suppressed to approximately 0.5% by weight or less, and concentrated products can be manufactured with a low loss rate by membrane concentration and freeze concentration methods. In conventional freeze concentration methods (for example, the interfacial advance freeze concentration method), approximately 2% by weight of the total solid content of the fluid to be treated before the freeze concentration treatment is discarded, resulting in a loss of solid content. However, in the freeze concentration method employed in the membrane concentration method and the freeze concentration method for producing concentrated products of the present invention, this loss can be suppressed to less than one-quarter of that of conventional freeze concentration methods. Furthermore, according to the present invention, since concentration is performed at low temperatures (such as 0 to 20°C) or below freezing point, where microbial growth is less likely to occur, the concentrated solution can be continuously processed (the freeze concentration device is operated) for a long period of time while suppressing microbial growth. Furthermore, in the freeze concentration method employed in the membrane concentration method and freeze concentration method for producing concentrated products of the present invention, the section for discharging the concentrated liquid and the section for removing water are separated. For example, in the case of concentrating dairy materials, the solid content concentration can be easily increased to about 30-40% by weight. Because the concentrated product obtained by this invention is not heated excessively, it is possible to commercially produce a concentrated product that can be stored stably for a long period of time while maintaining the original flavor derived from the processed fluid (dairy material, etc.). Furthermore, because the fluid to be processed is highly concentrated, concentrated foods (such as concentrated milk), which are difficult to sterilize continuously, can be hygienically concentrated by concentrating them at low temperatures (such as 0-20°C) or below freezing point, where microbial growth is less likely to occur. This allows for, for example, setting more lenient operating conditions for subsequent heat sterilization. According to the present invention, concentrated foods (such as concentrated milk) with high concentration, good flavor, or less heating odor, which could not be achieved by conventional methods, can be efficiently produced in a shorter time and with less loss of solids compared to conventional freeze-concentration methods. Furthermore, while conventional buttermilk and its processed products (such as concentrated liquids) are generally prone to flavor deterioration with heating and microbial growth even when stored under refrigeration, according to the present invention, when unpasteurized buttermilk is used as the fluid to be processed and concentrated buttermilk is produced, the concentrated buttermilk exhibits remarkable effects such as less flavor deterioration with heating and no microbial growth even when stored under refrigeration for several days. This is a schematic diagram illustrating an example of a series of apparatus configurations, including a membrane concentrator and a freeze concentrator, used when a concentrated product is manufactured according to the present invention. This is a schematic diagram illustrating a batch processing step according to the present invention. The present invention provides a method for producing a concentrated product by membrane concentration and freeze concentration, comprising a membrane concentration step of concentrating the fluid to be treated by the membrane concentration method to prepare a membrane-concentrated fluid to be treated. The freeze concentration method also comprises a step of using a suspension crystallization method (or suspension crystallization method) to concentrate the membrane-concentrated fluid to be treated after the membrane concentration step by generating granular ice crystals in the fluid to be treated after the membrane concentration step, which is placed in a crystallization tank. The subsequent freeze concentration method comprises an ice crystal generation step and an ice crystal separation step, which will be described later. In the membrane concentration process, the fluid to be treated is cooled (while cooling), and if necessary, the fluid to be treated is stirred, and the solid content concentration is increased to 1.5 times or more using one of the following: a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, or a microfiltration membrane, thereby preparing (manufacturing) a membrane-concentrated fluid to be treated. In this membrane concentration step, the concentration ratio and solid content of the membrane-concentrated fluid are not particularly limited as long as the solid content of the fluid to be treated can be concentrated (improved) to 1.5 times or more. However, from the viewpoint of efficiently shortening the processing time (concentration time) when converted to a unit volume (unit weight) of the fluid to be treated, the concentration ratio is specifically 1.5 to 3 times, preferably 1.6 to 2.7 times, more preferably 1.7 to 2.5 times, and even more preferably 1.8 to 2.2 times. The solid content is specifically 12 to 30% by weight, preferably 14 to 28% by weight, more preferably 16 to 25% by weight, and even more preferably 18 to 23% by weight. Furthermore, in the membrane concentration step, any known separation membrane can be used as long as the solid content concentration of the fluid to be treated can be concentrated to 1.5 times or more. However, from the viewpoint of separating necessary nutrients and efficiently removing water while suppressing the loss of solid content, the separation membrane is specifically a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, or a microfiltration membrane, preferably a reverse osmosis membrane, a nanofiltration membrane, or an ultrafiltration membrane, more preferably a reverse osmosis membrane, a nanofiltration membrane, or even more preferably a reverse osmosis membrane. Furthermore, in the membrane concentration process, the temperature of the fluid to be treated is not particularly limited as long as the solid content concentration of the fluid to be treated can be concentrated to 1.5 times or more. However, from the viewpoint of preventing microbial growth and enabling continuous processing over a long period of time while suppressing microbial growth, this temperature is specifically 0 to 25°C, preferably 2 to 20°C, more preferably 4 to 18°C, and even more preferably 6 to 15°C. If this temperature exceeds 25°C, the efficiency of the membrane concentration process improves, but if dairy materials are used in the fluid to be treated, microbial growth is more likely to be promoted, which may reduce the quality of the concentrated product. Also, if this temperature falls below 0°C, the fluid to be treated or the membrane-concentrated fluid to be treated may freeze and solidify, reducing the fluidity of the fluid to be treated or the membrane-concentrated fluid to be treated, which may reduce the efficiency of the membrane concentration process. In the ice crystal generation step used in the freeze concentration method performed after the membrane concentration step, the fluid to be treated with membrane concentration is cooled (while cooling), and if necessary, the fluid to be treated with membrane concentration is stirred, and ice crystals are generated in the fluid to be treated with membrane concentration, and a mixed fluid is produced consisting of the concentrated fluid to be treated, which has been concentrated by the generation of the ice crystals, and the ice crystals. In the subsequent ice crystal separation process, the mixed fluid is separated into the concentrated fluid to be treated and the ice crystals by a (solid-liquid) separation device such as a separation filter, and the concentrated fluid to be treated is removed. In this way, the fluid to be processed can be concentrated, and a concentrated product can be produced. During the concentration process, the fluid to be processed is not heated or warmed, and a concentrated product can be obtained without causing changes in flavor due to excessive heating or warming. Examples of fluids to be processed using the method for producing concentrated products according to the present invention include raw milk, skim milk, fermented milk (liquid fermented milk, drinkable yogurt, etc.), lactic acid bacteria beverages, whey, buttermilk, and milk materials containing milk components, such as concentrated liquids (membrane concentrates, etc.) thereof. In the membrane concentration method and freeze concentration method for producing concentrated products of the present invention, in the freeze concentration step, the ice crystal generation step described above and the subsequent ice crystal separation step described above can be repeated once or multiple times with respect to the fluid to be concentrated, which was extracted in the ice crystal separation step described above. In this way, concentration can be carried out at sub-zero temperatures where microbial growth is less likely to occur, and the number of microorganisms can be maintained or reduced while the solid content concentration can be easily increased to about 30-40% by weight in the case of dairy materials. In this case, in the second and subsequent ice crystal generation steps, a volume of membrane-concentrated fluid equivalent to the ice crystals separated in the previous ice crystal separation step is added to the concentrated fluid extracted in the previous ice crystal separation step to create a new concentrated fluid that can then be used in the second and subsequent ice crystal generation steps. Figure 1 is a schematic diagram showing an example of a membrane concentrator and a freeze concentrator used when a concentrated product is manufactured (a method for manufacturing a concentrated product is carried out) according to the present invention. Figure 2 is a schematic diagram showing an overview of the processing steps when batch processing is performed using a part of the configuration shown in Figure 1. A preferred embodiment of the present invention will be further described using Figure 1. In the apparatus configuration illustrated in Figure 1, the fluid to be processed (for example, raw milk) is first subjected to membrane concentration treatment using a reverse osmosis (RO) membrane at a predetermined low temperature (0 to 20°C). Then, if necessary, it is sterilized using a known sterilizer as illustrated in Figure 1, and sent to a concentration process using the freeze concentration method. In the concentration process using the freeze concentration method, the freeze concentration apparatus illustrated in Figure 1 is used. The freeze-concentration apparatus shown in Figure 1 comprises a crystal formation tank (jacketed tank) into which the fluid to be processed (for example, membrane-concentrated raw milk concentrated in the membrane concentration process described above) is fed (for example, inner diameter: 20 cm, height: 100 cm, shape of stirring blades: gantry type, capacity: 140 kg), and a crystal separation column equipped with a separation filter. The crystal formation tank and the crystal separation column are connected via a transfer pump that transfers the mixed fluid from the crystal formation tank to the crystal separation column. A refrigerant (ammonia, glycol, etc.) is supplied from a refrigerator to the jacket attached to the crystal formation tank. The refrigerant supplied from the refrigerator flows through the jacket, indirectly cooling the fluid to be processed (such as membrane-concentrated raw milk) in the crystal formation tank. Alternatively, a gate-shaped agitator can be installed inside the crystal formation tank, and if necessary, the fluid to be processed (such as membrane-concentrated raw milk) can be efficiently cooled while being stirred using this agitator. Here, we describe a jacketed tank equipped with stirring blades as a tank with a stirring function, but the invention is not limited to this jacketed tank as long as a similar effect can be obtained. Furthermore, if the shape can obtain the same stirring effect as a gate-type stirring blade, the shape is not limited to the stirring method using a gate-type stirring blade. For example, a coil-shaped stirring blade can be used, as well as sawtooth disc turbines, pitched turbines, anchor-type, propeller-type, and other shapes of stirring blades. Furthermore, in order to shorten the time required to generate ice crystals, it is preferable to pass the refrigerant through the jacket and, separately, through the stirring blades. One method of passing the refrigerant is to provide a cooling means in the tank, as is conventionally known, in which the refrigerant circulates within the tank. By passing the refrigerant through such a method, the refrigerant can be passed through the stirring blades of various shapes as exemplified above, thereby shortening the time required to generate ice crystals. The mixed fluid of ice crystals supplied to the crystal separation column via a transfer pump and the concentrated fluid to be processed (such as membrane-concentrated raw milk) that has been concentrated by the formation of these ice crystals is separated into ice crystals and concentrated fluid by the separation device of the crystal separation column. The separated ice crystals are melted with hot water or the like and discharged as separated water outside the freeze-concentrating device. While a separation filter can be used in the separation device of the crystal separation column, the crystal separation method is not limited to the separation filter, and for example, a centrifuge can also be used. Alternatively, the ice crystals can be separated by standing. When separating ice crystals from the concentrated fluid to be treated by static separation, a static separation tank is used. The mixed fluid is transferred from the jacketed tank to the static separation tank and allowed to stand. Inside the tank, a layer of ice crystals forms on the upper side, and a phase of the concentrated fluid to be treated forms on the lower side. When the solid content in the concentrated fluid to be treated reaches the desired concentration, the concentrated fluid and ice crystals are discharged from the static separation tank. The concentrated fluid to be treated (concentrated liquid) is extracted as a concentrated product manufactured by the method of the present invention, but all or part of it can be returned to the crystal generation tank for further concentration (ice crystal generation step, ice crystal separation step). For this reason, a return (circulation) means to the crystal generation tank can be provided in the middle of the discharge pipe of the concentrated fluid to be treated (concentrated liquid). Thus, according to the present invention, there is a section for removing water (separating the ice crystals of the fluid to be treated generated in the crystal generation tank using a crystal separation column) and a section for discharging the concentrated liquid (taking out the concentrated fluid to be treated as a concentrated product produced by the method of the present invention). The supply pipe that supplies and introduces the fluid to be processed into the crystal formation tank is equipped with a supply volume adjustment mechanism. This supply volume adjustment mechanism allows the weight and volume of the fluid to be processed (such as membrane-concentrated raw milk) supplied and introduced into the crystal formation tank to be adjusted according to the weight and volume of the concentrated fluid to be processed (concentrated liquid) that is returned to the crystal formation tank via the return (circulation) mechanism. For example, when the concentrated fluid to be processed (concentrated liquid) is returned to the crystal formation tank via the return means, the weight and volume of the separated water (equivalent to the weight and volume of separated ice crystals) of the fluid to be processed (such as membrane-concentrated raw milk) that is separated by the separation filter of the crystal separation column, melted with hot water, etc., and discharged outside the system of the freeze-concentrating apparatus is adjusted and controlled by the supply amount adjustment means, and supplied and introduced into the crystal formation tank from the supply pipe. In the ice crystal generation process, the fluid to be processed is cooled and, if necessary, stirred to generate ice crystals in the fluid to be processed (such as membrane-concentrated raw milk). As a result of the generation of the ice crystals, a mixed fluid is produced consisting of a concentrated fluid, which is further concentrated by the formation of the ice crystals, and the ice crystals. As described above, a jacketed tank equipped with a stirring function can be used as the crystal formation tank (crystallization tank) in which the ice crystal formation process takes place. For example, a tank with an inner diameter of 20 cm and a depth of 100 cm, equipped with gate-shaped stirring blades, can be used to stir the fluid to be processed contained in the tank at 60 to 300 rpm, preferably 100 to 200 rpm. It is considered that the formation of ice crystals can be appropriately controlled if the shear stress and Reynolds number are similar to those of the fluid to be processed mentioned in the above example, so the rotation speed of the stirring blades can be freely set. A refrigerant, such as ammonia, is supplied from a chiller to a jacket located on the outside of the tank. The temperature of the refrigerant should be within a range that allows ice crystals to form in the fluid to be processed (such as membrane-concentrated raw milk) contained in the tank, and is generally below -2°C, for example, between -6°C and -8°C. The fluid to be concentrated (such as membrane-concentrated raw milk) is placed in a jacketed tank (crystal generation tank), and the fluid is cooled by passing a refrigerant at -6 to -8°C through the jacket to generate ice crystals. In this case, the stirring blades of the tank can also be rotated to stir the fluid at 60 to 300 rpm while cooling the fluid to generate ice crystals. Furthermore, in order to shorten the time required to generate ice crystals, the refrigerant may be passed through the jacket, or separately, through the stirring blades. One method for passing the refrigerant through the stirring blades is to provide a cooling means in the tank, as is conventionally known, in which the refrigerant circulates within the tank. By using such a method of passing the refrigerant through the stirring blades of various shapes as exemplified above, the time required to generate ice crystals can be shortened. The required ice crystal size varies depending on the freezing temperature and concentration ratio of the fluid to be processed (such as membrane-concentrated raw milk), but for example, it is cooled to 0.0°C to -2.5°C, and then the ice crystals of the fluid to be processed are grown to an average size of 100 μm or more for 2 to 5 hours, preferably 3 to 5 hours. In other words, the average size of ice crystals in typical ice cream is said to be about 30 to 40 μm immediately after freezing, and about 45 to 55 μm after complete hardening. In the freeze-concentration process of the present invention, the average size of the ice crystals of the fluid to be processed is grown to 100 μm or more, which is larger than the average size of ice crystals in typical ice cream, from the viewpoint of the short time required to generate ice crystals and the ease of separation by separation filter. At this time, the average size of the ice crystals in the fluid to be treated is grown to a size of 100 to 3000 μm, preferably 150 to 2500 μm, more preferably 200 to 2000 μm, even more preferably 250 to 1500 μm, and particularly preferably 300 to 1000 μm. Furthermore, when cooling the fluid to be processed (such as membrane-concentrated raw milk) while stirring it, it is desirable to keep the concentration of ice crystals in the fluid to be processed to 50% by weight or less, preferably 45% by weight or less, and more preferably 40% by weight or less, from the viewpoint of being able to smoothly stir the fluid to be processed. However, if the fluid to be processed can be stirred with a predetermined power, there is no problem even if ice crystals are present at a concentration of 50% or more of the total weight. Subsequently, the mixture of the concentrated fluid (such as membrane-concentrated raw milk) and the ice crystals, which has been further concentrated by the formation of ice crystals, is sent from the jacketed tank (crystal formation tank) to the crystal separation column, where the ice crystal separation process takes place. At this point, when a predetermined concentration ratio is reached during the ice crystal formation process, the aforementioned mixture can be sent from the jacketed tank (crystal formation tank) to the crystal separation column to proceed to the ice crystal separation process. When transitioning from the ice crystal generation process to the ice crystal separation process, the degree of concentration (concentration ratio) of the fluid to be processed (such as membrane-concentrated raw milk) depends on the type and characteristics of the fluid to be processed. For example, when the concentration ratio reaches about 3 times (when the temperature of the fluid to be processed drops to -2.5°C to -2.0°C), the aforementioned mixed fluid can be transferred from the jacketed tank (crystal generation tank) to the crystal separation column to perform the ice crystal separation process. Furthermore, by supplying the fluid to be processed (such as membrane-concentrated raw milk) to the crystallization tank in an amount equivalent to the volume (weight or volume) of the mixed fluid sent from the jacketed tank (crystallization tank) to the crystallization column, the freeze-concentration apparatus can be operated continuously in this invention. Also, as shown in Figure 2, processing can be carried out in a batch manner. In the ice crystal separation process, the ice crystals are separated from the concentrated fluid (concentrate) by the separation device of the crystal separation column, and the concentrated fluid (concentrate) is removed. The separated ice crystals are melted with hot water or the like, and the separated water is discharged from the freeze concentration system. When using a separation filter in the separation device of a crystal separation column, the dimensions of the separation filter are such that they separate the ice crystals generated in the ice crystal formation process. Therefore, as mentioned above, if you want to grow the average size of the ice crystals in the fluid being treated to 100 μm or more, you should use a separation filter with dimensions of approximately 100 μm or more. The dimensions of the separation filter can be determined appropriately considering the type and characteristics of the fluid to be processed, the dimensions of the ice crystals produced in the ice crystal formation process, and the processing efficiency of the fluid to be processed, but at a minimum, a filter with dimensions that can separate the ice crystals produced in the ice crystal formation process should be used. Separation can also be performed by static standing. When separating ice crystals from the concentrated fluid to be treated by static standing, a tank for static standing separation is used. The mixed fluid is sent from the jacketed tank to the tank for static standing separation and left to stand. In the tank, a layer of ice crystals forms on the upper side and a phase of the concentrated fluid to be treated forms on the lower side. When the solid content in the concentrated fluid to be treated reaches the desired concentration, the concentrated fluid to be treated and the ice crystals are discharged from the tank for static standing separation. The concentrated fluid to be treated (concentrate) separated from the ice crystals can be used as is to produce the concentrated product manufactured by the present invention, or it can be subjected to the ice crystal generation process and the subsequent ice crystal separation process again to increase the degree of concentration (concentration ratio). For example, the concentrated fluid to be treated (concentrate) obtained in the ice crystal separation process can be easily concentrated to a high concentration of 20 to 50% by weight, preferably 25 to 45% by weight, and more preferably 30 to 40% by weight, by repeating the aforementioned ice crystal generation process and the subsequent ice crystal separation process one or more times. At this time, such a solid content concentration is considered preferable from the viewpoint of effectively maintaining and improving the good physical properties, quality, and flavor of the raw milk (milk material). Figure 1 illustrates the flow in which a portion of the concentrated fluid (concentrate) separated from the ice crystals is taken out to become the concentrated product manufactured according to the present invention, and the remaining portion is subjected to the ice crystal generation process and the subsequent ice crystal separation process again in order to further increase the concentration ratio. Furthermore, in the second and subsequent ice crystal generation processes, the concentrated fluid to be treated (concentrated liquid) extracted in the preceding ice crystal separation process can be further treated by adding a volume (weight or volume) of the fluid to be treated (the membrane-concentrated fluid to be treated after membrane concentration) equivalent to the ice crystals separated in the preceding ice crystal separation process to create a new fluid to be concentrated, and then proceeding with the second and subsequent ice crystal generation processes. In any case, by repeatedly performing the aforementioned ice crystal formation process and the aforementioned ice crystal separation process, the concentration ratio can be gradually increased. Furthermore, when converted to solid content, the waste loss rate can be reduced to 0.5% by weight or less. As mentioned above, the raw milk (milk material) to be processed is not particularly limited as long as it contains milk components, but if we were to distinguish it from the expression "raw milk" and give examples, they would include raw milk, skim milk, fermented milk (liquid fermented milk, drinkable yogurt, etc.), lactic acid bacteria beverages, whey, buttermilk, and concentrated liquids of these (membrane concentrates, etc.). Using these milk materials as the fluid to be processed, concentrated products (freeze-concentrated dairy foods) such as concentrated milk, concentrated skim milk, concentrated fermented milk (concentrated liquid fermented milk, concentrated drinkable yogurt, etc.), concentrated lactic acid bacteria beverages, concentrated whey, and concentrated buttermilk can be produced to which the present invention is applied. In this process, from the viewpoint of effectively maintaining and improving the good physical properties, quality, and flavor of the raw milk (dairy material), raw milk, skim milk, fermented milk (liquid fermented milk, drinkable yogurt, etc.), lactic acid bacteria beverages, and buttermilk are preferred as the fluid to be processed. Furthermore, from the viewpoint of improving the number of viable beneficial microorganisms (lactic acid bacteria, bifidobacteria, yeast, etc.) in the raw milk (dairy material), fermented milk (liquid fermented milk, drinkable yogurt, etc.) and lactic acid bacteria beverages are preferred as the fluid to be processed. Moreover, from the viewpoint of improving the (refrigerated) shelf life of the raw milk (dairy material), raw milk, skim milk, and buttermilk (including butter gelam in the concept of buttermilk) are preferred as the fluid to be processed, and from the viewpoint of the magnitude of the effect, buttermilk is more preferred. In the freeze concentration process (suspension crystallization method (or suspension crystallization method)) employed in the freeze concentration step of the manufacturing method of the present invention, the specific method is not particularly limited, and any known method may be used, and there is no particular prejudice to combining it with a known method. In the freeze concentration process used in the manufacturing method of the present invention, the method of combining it with a method of deoxygenating the fluid to be processed (e.g., dairy material) is expected to suppress changes in the flavor of the resulting fluid to be processed (e.g., freeze-concentrated dairy material) during (refrigerated) storage. In this case, the deoxygenation process is not particularly limited as long as it is a method that reduces the dissolved oxygen concentration of the fluid to be processed, but examples include gas displacement methods using an inert gas such as nitrogen, reduced pressure degassing methods using a vacuum degasser, membrane deoxygenation methods using a hollow membrane, etc. When a dairy product is used as the fluid to be processed, the concentrated product (freeze-concentrated dairy food) obtained based on the present invention can be used in the same way as conventional concentrated products (vacuum-heated concentrated dairy food). In particular, the effects of the present invention can be strongly expected in freeze-concentrated buttermilk because oxidation and photodegradation can be effectively suppressed and prevented. Furthermore, when a dairy material is used as the fluid to be processed, the concentrated product (freeze-concentrated dairy food) obtained based on the present invention can retain aroma components (highly volatile aroma components such as acetone and 2-butanone) at a rate of preferably 3 times or more, more preferably 5 times or more, even more preferably 7 times or more, and particularly preferably 9 times or more, compared to conventional concentrated products (vacuum-heated concentrated dairy food). And, when raw milk, skim milk, or buttermilk, preferably buttermilk, is used as the fluid to be processed, the concentrated product (freeze-concentrated dairy food) obtained based on the present invention can retain aroma components at a rate of preferably 0.7 times or more, more preferably 0.8 times or more, even more preferably 0.9 times or more, and particularly preferably 1 time or more, compared to the unprocessed product. On the other hand, when using, as the fluid to be treated, among dairy materials, fermented milk (such as liquid fermented milk, drinkable yogurt, etc.) or lactic acid bacteria beverages, in the concentrated product (frozen concentrated dairy food) obtained based on the present invention, the viable count of useful microorganisms (such as lactic acid bacteria, bifidobacterium, yeast, etc.) can be preferably maintained at 0.7 times or more, more preferably 0.8 times or more, still more preferably 0.9 times or more, and particularly preferably 1 time or more compared to the untreated product. And when using, as the fluid to be treated, preferably fermented milk (such as liquid fermented milk, drinkable yogurt, etc.) among dairy materials, in the concentrated product (frozen concentrated dairy food) obtained based on the present invention, the viable count of useful microorganisms (such as lactic acid bacteria, bifidobacterium, yeast, etc.) can be preferably maintained at 5×10⁶ cfu / g or more, more preferably 10⁷ cfu / g or more, still more preferably 5×10⁷ cfu / g or more, and particularly preferably 10⁸ cfu / g or more compared to the untreated product. FIG. 2 is a schematic diagram showing an example of a freeze concentration apparatus when a concentrated product is manufactured (a method for manufacturing a concentrated product is carried out) by performing, in a batchwise manner, the process of preparing the membrane concentrated fluid to be treated described above, the process of making the concentrated fluid to be treated, which is further concentrated from the fluid to be treated, into a mixed fluid with the ice crystals, and the process of separating the mixed fluid into the concentrated fluid to be treated and the ice crystals and taking out the concentrated fluid to be treated. In the apparatus configuration illustrated in FIG. 2, first, the fluid to be treated (for example, raw milk) is subjected to a membrane concentration treatment by a reverse osmosis membrane (RO membrane) in a predetermined low temperature state (0 to 20°C). For example, the fluid to be treated with a solid content concentration of 9% by weight is concentrated to 15% by weight. Thereafter, it is sterilized by a known sterilizer and sent to a concentration step by a freeze concentration method. In the concentration step by a freeze concentration method, the freeze concentration apparatus illustrated in FIG. 2 is used. The freezing concentration device shown in Fig. 2 includes a crystal generation tank (jacketed tank) (for example, inner diameter: 50 cm, height: 70 cm, shape of stirring blades: coil type, capacity: 140 kg) into which a processing fluid (for example, the membrane-concentrated raw milk concentrated in the membrane concentration step as described above) is introduced, and a tank for static separation treatment (static separation treatment tank). The crystal generation tank and the tank for static separation treatment (static separation treatment tank) are connected via a transfer pump (not shown) that transfers the mixed fluid from the crystal generation tank to the tank for static separation treatment (static separation treatment tank). The crystal generation tank shown in Fig. 2 is provided with a jacket to which a refrigerant (ammonia, glycol, etc.) is supplied from a refrigerator. Also, a cooling means for circulating the refrigerant inside the crystal generation tank is provided. When the refrigerant supplied from the refrigerator flows in the jacket, or when the refrigerant circulates inside the crystal generation tank by the cooling means and is passed through the stirring blades, the processing fluid (such as membrane-concentrated raw milk) inside the crystal generation tank is indirectly cooled, ice crystals of the processing fluid (such as membrane-concentrated raw milk) are generated in the processing fluid (such as membrane-concentrated raw milk), and a mixed fluid of the concentrated processing fluid in which the processing fluid (such as membrane-concentrated raw milk) is further concentrated due to the generation of the ice crystals and the ice crystals is generated. The mixed fluid of the ice crystals supplied via a transfer pump into the tank for static separation treatment (static separation treatment tank) and the concentrated processing fluid in which the processing fluid (such as membrane-concentrated raw milk) is concentrated due to the generation of the ice crystals is separated into ice crystals and the concentrated processing fluid (concentrate) by standing still in the tank, and the concentrated processing fluid (concentrate) is taken out. The separated ice crystals are melted by warm water or the like and discharged outside the system of the freezing concentration device as separated water. Thus, separately from the freezing concentration device described with reference to Fig. 1, the membrane-concentrated processing fluid adjustment step, the ice crystal generation step, and the ice crystal separation step can also be processed batchwise. The following describes an example of a method for producing a concentrated product according to the present invention, using a series of devices consisting of a membrane concentration apparatus and a freeze concentration apparatus, the schematic configurations of which are shown in Figures 1 and 2. However, the present invention is not limited to the preferred embodiments described above or the following examples, and can be modified in various forms within the technical scope as understood from the claims. [Example 1] 100 kg of raw milk (raw milk, solid content concentration: 12.3% by weight) was used as the fluid to be treated. This raw milk was kept at approximately 10°C and subjected to membrane concentration treatment using a reverse osmosis membrane (RO membrane) to obtain a membrane-concentrated fluid (approximately 1.8 times concentrated compared to the raw milk, solid content concentration: approximately 22% by weight). This membrane-concentrated fluid was introduced into a crystal formation tank (jacketed tank) (inner diameter: 20 cm, height: 100 cm, stirring blade shape: gantry type, capacity: 140 kg). A refrigerant controlled to -6 to -8°C was passed through the jacket via a commercially available refrigerator, and stirring and cooling were started in the jacketed tank (stirring speed: 150 rpm). After five hours, it was confirmed that the temperature of the condensed milk, the fluid being treated, was -1.9°C, the solid content concentration of the condensed milk was 32% by weight, and the ice crystal concentration was 30% by weight. Subsequently, the liquid was started to flow from the crystal generation tank to the crystal separation column (the separation filter used here has dimensions of 100 μm) (flow rate: 0.5 liters / second). The ice crystals separated by the crystal separation column were discharged, and the entire volume of concentrated milk that had permeated (passed through) the crystal separation column was returned to the crystal formation tank. At this time, the aforementioned membrane-concentrated fluid (approximately twice the concentration of the raw milk, solid content concentration: approximately 24% by weight) was continuously added to the crystal formation tank so that its weight was equal to the weight of the ice crystals separated and discharged by the crystal separation column. When this process was continued for approximately 30 hours, concentrated milk (concentrated product) with a solid content of 32% by weight and a temperature of -1.9°C was continuously obtained. Furthermore, the ice crystals discharged at this time contained only 0.3 kg of milk solids. In other words, the amount of milk solids not recovered into the concentrated milk was only 0.3% by weight of the total. In this embodiment, the process is carried out continuously according to the steps shown in Figure 1, but it is also possible to carry out the process batch-wise according to the steps shown in Figure 2. [Example 2] 100 kg of buttermilk (raw milk, solids concentration: 10.6% by weight) was used as the fluid to be treated. This buttermilk was kept at approximately 10°C and subjected to membrane concentration treatment using a reverse osmosis membrane (RO membrane) to obtain a membrane-concentrated fluid (approximately 1.7 times concentrated compared to the raw milk, solids concentration: approximately 18% by weight). This membrane-concentrated fluid was introduced into a crystal formation tank (jacketed tank) (inner diameter: 20 cm, height: 100 cm, stirring blade shape: gantry type, capacity: 140 kg). A refrigerant controlled to -6 to -8°C was passed through the jacket via a commercially available refrigerator, and stirring and cooling were started in the jacketed tank (stirring speed: 150 rpm). After five hours, it was confirmed that the temperature of the treated fluid, concentrated buttermilk, was -1.9°C, the solid content concentration of concentrated buttermilk was 32% by weight, and the ice crystal concentration was 30% by weight. Subsequently, the liquid was started to flow from the crystal generation tank to the crystal separation column (the separation filter used here has dimensions of 100 μm) (flow rate: 0.5 liters / second). The ice crystals separated by the crystal separation column were discharged, and the entire volume of concentrated buttermilk that had permeated the crystal separation column was returned to the crystal formation tank. At this time, the aforementioned membrane-concentrated fluid (approximately twice the concentration of the raw milk, solid content concentration: approximately 21% by weight) was continuously added to the crystal formation tank so that its weight was equal to the weight of the ice crystals separated and discharged by the crystal separation column. When this process was continued for approximately 30 hours, concentrated buttermilk (concentrated product) with a solid content of 32% by weight and a temperature of -1.9°C was continuously obtained. Furthermore, the ice crystals discharged at this time contained only 0.2 kg of milk solids. In other words, the amount of milk solids not recovered into the concentrated buttermilk was only 0.2% by weight of the total. In this embodiment, the process is carried out continuously according to the steps shown in Figure 1, but it is also possible to carry out the process batch-wise according to the steps shown in Figure 2. [Example 3] 100 kg of skim milk (raw milk, solid content concentration: 9.0% by weight) was used as the fluid to be treated. This skim milk was kept at approximately 10°C and subjected to membrane concentration treatment using a reverse osmosis membrane (RO membrane) to obtain a membrane-concentrated fluid (approximately 1.8 times concentrated compared to the raw milk, solid content concentration: approximately 16% by weight). This membrane-concentrated fluid was introduced into a crystal formation tank (jacketed tank) (inner diameter: 20 cm, height: 100 cm, stirring blade shape: gantry type, capacity: 140 kg). A refrigerant controlled to -6 to -8°C was passed through the jacket via a commercially available refrigerator, and stirring and cooling were started in the jacketed tank (stirring speed: 150 rpm). After five hours, it was confirmed that the temperature of the concentrated skim milk, the fluid being treated, was -1.9°C, the solid content concentration of the concentrated skim milk was 36% by weight, and the ice crystal concentration was 30% by weight. Subsequently, the liquid was started to flow from the crystal generation tank to the crystal separation column (the separation filter used here has dimensions of 100 μm) (flow rate: 0.5 liters / second). The ice crystals separated by the crystal separation column were discharged, and the entire volume of concentrated buttermilk that had permeated the crystal separation column was returned to the crystal formation tank. At this time, the aforementioned membrane-concentrated fluid (approximately twice the concentration of the raw milk, solid content concentration: approximately 18% by weight) was continuously added to the crystal formation tank so that its weight was equal to the weight of the ice crystals separated and discharged by the crystal separation column. When this process was continued for approximately 30 hours, concentrated skim milk (concentrated product) with a solid content of 36% by weight and a temperature of -1.9°C was continuously obtained. Furthermore, the ice crystals discharged at this time contained only 0.5 kg of milk solids. In other words, the amount of milk solids not recovered in the concentrated milk was only 0.5% by weight of the total. In this embodiment, the process is carried out continuously according to the steps shown in Figure 1, but it is also possible to carry out the process batch-wise according to the steps shown in Figure 2. [Example 4] The case in which processing is performed batch by batch according to the steps shown in Figure 2 will be explained. 180 kg of skim milk (raw milk, solids content: 9.0%) was used as the fluid to be treated. This skim milk was kept at approximately 10°C and subjected to membrane concentration treatment using a reverse osmosis membrane (RO membrane, operating pressure 0.8-4 MPa, permeate discharge rate 4-14 kg / m² / h) to obtain a membrane-concentrated fluid (approximately 1.7 times concentrated from the raw milk: solids content approximately 15%). This membrane-concentrated fluid was then introduced into a crystal formation tank (jacketed tank) (inner diameter: 50 cm, height: 70 cm, stirring blade shape: coil type, capacity: 140 kg). A refrigerant controlled to -6 to -8°C was passed through the jacket via a commercially available refrigerator (not shown), and stirring and cooling were started in the jacketed tank (stirring speed: 57 rpm). After five hours, it was confirmed that the temperature of the concentrated skim milk, the fluid being treated, was -1.2°C, the solid content concentration of the concentrated skim milk was 23% by weight, and the ice crystal concentration was 37% by weight. The fluid to be treated, in which ice crystals were dispersed, was removed from the jacketed tank, and the mixed fluid was transferred from the jacketed tank to a tank for static separation treatment (static separation treatment tank), where it was allowed to stand and separate the ice crystals. After approximately 15 minutes, the concentration of milk solids contained in the ice crystals was 0.1% by weight. In this embodiment, the processing was carried out batch by following the steps shown in Figure 2, but it is also possible to carry out the processing continuously by following the steps shown in Figure 1. Furthermore, when cooling a jacketed tank, it was confirmed that if a cooling means is provided within the tank that circulates refrigerant not only through the jacket but also through coil-shaped stirring blades, the ice crystal concentration can reach the desired concentration in a short time. [Comparative Example 1] 100 kg of raw milk (raw milk, solids content: 12.3% by weight) was used as the fluid to be processed. This raw milk was put into a crystal formation tank (jacketed tank) (inner diameter: 20 cm, height: 100 cm, shape of stirring blades: gantry type, capacity: 140 kg). A refrigerant controlled to -6 to -8°C was passed through the jacket via a commercially available refrigerator, and stirring and cooling were started in the jacketed tank (stirring speed: 150 rpm). After five hours, it was confirmed that the temperature of the condensed milk, the fluid being treated, was -0.4°C, the solid content concentration of the condensed milk was 15% by weight, and the ice crystal concentration was 30% by weight. Subsequently, the liquid was started flowing from the crystal generation tank to the crystal separation device (the separation filter used here has dimensions of 100 μm) (flow rate: 0.5 liters / second). The ice crystals separated by the crystal separation device were discharged, and the entire volume of concentrated milk that had passed through the crystal separation device was returned to the crystal generation tank. At this time, raw milk (raw material, solid content concentration: 12.3% by weight) was continuously added to the crystal generation tank so that its weight was equal to the weight of the ice crystals separated and discharged by the crystal separation device. By continuing this process for approximately 40 hours, we were able to continuously obtain concentrated milk (concentrated product) with a solid content of 32% by weight and a temperature of -1.9°C.

Claims

Revised 13 / 09 / 2018 Claims: None ----------------------------------------------------------------------------- Revised 28 / 04 / 2016 1. Methods for producing concentrated products using the membrane-concentration method and the freeze-concentration method, which include: the membrane-concentration step where the fluid to be concentrated is cooled and the membrane-concentrated fluid is prepared by membrane concentration until the solids content of this fluid is greater than 1.5 times concentration is achieved using one of the following types of membranes: reverse osmositic membrane, nanofiltration membrane, ultrafiltration membrane, and precision filtration membrane. The ice crystallization process involves cooling the membrane-concentrated fluid, causing ice crystals to form within the concentrated fluid. This results in a concentrated fluid mixture containing the ice crystals and the concentrated fluid produced from the membrane-concentrated fluid. The ice crystal separation process separates the concentrated fluid into the concentrated fluid and the ice crystals, and the concentrated fluid is then recovered.The methods for producing concentrated products using the pulp concentrater and cryo-concentrate methods according to claim 1, where the preparation of the pulp concentrater fluid, the formation of the resulting fluid mixture containing the resulting ice crystals and the resulting concentrater fluid produced from the pulp concentrater fluid, the further concentration of the resulting concentrater fluid produced from the pulp concentrater fluid, the separation of the resulting fluid mixture into the resulting concentrater fluid and the resulting ice crystals, and the recovery of the resulting concentrater fluid are performed in a batch basis.3.Methods for producing concentrated products using the pulp concentration method and the freeze-drying concentration method according to claim 1 or 2, where the aforementioned ice crystallization step and the aforementioned ice crystallization step after the ice crystallization step are repeated one or more times for the concentrated fluid to be concentrated that is recovered during the ice crystallization step. 4.The method for producing concentrated products using the pulp concentrater and cryoconcentrate methods according to claim 3, whereby the aforementioned ice crystallization steps, after the second and subsequent steps, are performed for a new set of concentrates obtained by immediately adding the pulp concentrater fluid prepared by the pulp concentrater step, which has the same capacity as the ice crystals separated during the previous ice crystallization step, to the concentrates to be made from the concentrates recovered during the previous ice crystallization step.5.

6. A method of producing concentrated products using pulp concentrate and freeze concentrate methods according to one of the claims in Cases 1 to 4, where the concentrate fluid is one of the fluids of raw milk, skimmed milk, fermented milk (e.g., liquid sour milk, ready-to-drink yogurt, lactic acid beverage, whey, and buttermilk.

7. A method of producing concentrated products using pulp concentrate and freeze concentrate methods according to one of the claims in Cases 1 to 5, where, compared to the unconcentrated product, the concentrated product obtained by any of the methods described in Cases 1 to 5 has 0.7 times more of the fragrance component.Methods for producing concentrated products using the membrane concentration method and the freeze-concentration method according to any one of the claims 1 to 6, where, compared to the unconcentrated product, the concentrated product obtained by any of the methods described in claims 1 to 6 contains 0.7 times more live bacteria of beneficial microorganisms.---------------------------------------------------1. Methods for producing concentrated products using the membrane concentration method and the freeze-concentration method, which include: a membrane concentration step where the fluid to be concentrated is cooled and the membrane-concentrated fluid is prepared by membrane concentration until the solids content of this fluid is greater than 1.5 times concentration is achieved using one of the following types of membranes: reverse osmositic membrane, nanofiltration membrane, ultrafiltration membrane, and precision filtration membrane. The ice crystallization process involves cooling the membrane-concentrated fluid, causing ice crystals to form within the concentrated fluid. This results in a concentrated fluid mixture containing the ice crystals and the concentrated fluid produced from the membrane-concentrated fluid. The ice crystal separation process separates the concentrated fluid into the concentrated fluid and the ice crystals, and the concentrated fluid is then recovered.The methods for producing concentrated products using the pulp concentrater and cryo-concentrate methods according to claim 1, where the preparation of the pulp concentrater fluid, the formation of the resulting fluid mixture containing the resulting ice crystals and the resulting concentrater fluid produced from the pulp concentrater fluid, the further concentration of the resulting concentrater fluid produced from the pulp concentrater fluid, the separation of the resulting fluid mixture into the resulting concentrater fluid and the resulting ice crystals, and the recovery of the resulting concentrater fluid are performed in a batch basis.3.Methods for producing concentrated products using the pulp concentration method and the freeze-drying concentration method according to claim 1 or 2, where the ice crystallization step and the ice crystal separation step are repeated one or more times for the concentrated fluid to be concentrated that is recovered during the ice crystal separation step. 4.The method for producing concentrated products using the pulp concentrater and cryoconcentrate methods according to claim 3, where the aforementioned ice crystallization steps, after the second and subsequent steps, are performed for a new set of concentrates obtained by immediately adding the pulp concentrater fluid prepared by the pulp concentrater step, which has the same capacity as the ice crystals separated during the previous ice crystallization step, to the concentrates to be made from the concentrates recovered during the previous ice crystallization step.5.

6. A method of producing concentrated products using pulp concentrate and freeze concentrate methods according to one of the claims in Cases 1 to 4, where the concentrate fluid is one of the fluids of raw milk, skimmed milk, fermented milk (e.g., liquid sour milk, ready-to-drink yogurt, lactic acid beverage, whey, and buttermilk.

7. A method of producing concentrated products using pulp concentrate and freeze concentrate methods according to one of the claims in Cases 1 to 5, where, compared to the unconcentrated product, the concentrated product obtained by any of the methods described in Cases 1 to 5 has 0.7 times more of the fragrance component.The production method of concentrated products using the pulp concentration method and the freeze-dry concentration method according to any of the claims 1 to 6, where, compared to the unconcentrated product, the concentrated product obtained by any of the production methods described in claims 1 to 6 contains more than 0.7 times the live bacteria of beneficial microorganisms;