WO2004045316A1 - Method of processing liquid food and processing apparatus - Google Patents

Abstract

A method of processing a liquid food, characterized by comprising the first step of introducing pressurized carbon dioxide in a processing tank charged with a liquid food and circulating under agitation pressurized carbon dioxide through the liquid food in the processing tank so as to dissolve carbon dioxide in the liquid food and to uniformize the concentration of dissolved carbon dioxide in the liquid food; the second step of sustaining such conditions that any enzymes contained in the liquid food are deactivated and/or any microorganisms contained therein are annihilated while maintaining the concentration of dissolved carbon dioxide in the liquid food at a constant level; and the third step of discharging portion of pressurized carbon dioxide and thereafter passing an inert gas through the liquid food so as to circulate under agitation the inert gas through the liquid food in the processing tank, thereby removing dissolved carbon dioxide. There is further provided an apparatus for carrying out the method. These method and apparatus enable not only without escape of scent of the liquid food, realizing efficient sterilization and enzyme deactivation but also efficiently removing carbon dioxide dissolved in the liquid food to thereby minimize the loss of scent components.

Description

 Description Liquid food processing method and processing equipment

Technical field

 The present invention is directed to a liquid food that can efficiently dissolve pressurized carbon dioxide in a liquid food, enhance sterilization and enzyme killing effects, and efficiently remove dissolved carbon dioxide without losing the aroma of the liquid food. The present invention relates to a processing method and a processing apparatus. Background art

 In recent years, there has been a demand for maintaining the quality, freshness and naturalness of foods, reducing the amount of additives to foods, and avoiding excessive heating of foods to sterilize foods. Therefore, there is a growing demand for technologies that can replace food heating, and non-heat sterilization of liquid foods using pressurized carbon dioxide has high potential as a next-generation technology. Development is underway.

 The present inventors believe that the sterilization effect of the non-heat sterilization method for liquid foods using pressurized carbon dioxide varies remarkably, and this is attributed to the low degree of contact between the cells and carbon dioxide. The present inventors have found a method of strongly increasing the contact, and have been able to propose a pasteurization technique having a remarkably enhanced sterilization effect (Japanese Patent Application Laid-Open No. 7-170965). The point of the above technology is that by injecting carbon dioxide into the system in fine bubbles through the filter, the solubility of carbon dioxide can reach 98% of the saturated solubility of carbon dioxide in the system. is there. Specifically, we proposed a method of inactivating enzymes by bringing supercritical carbon dioxide into contact with enzyme-containing liquid food.

According to the method described in Japanese Patent Application Laid-Open No. 7-170965, The enzyme-containing liquid food is stored, and the inside of the treatment tank is maintained at a predetermined temperature and pressure condition in a sealed state. A supercritical fluid of carbon dioxide is passed through the filter through the filter to a very small size (average diameter: 1). (Less than 0,0 m), the supercritical fluid is easily dissolved in the liquid food. According to this method, not only can the enzyme be efficiently deactivated, but also the safety is high because only carbon dioxide comes into contact with food. Further, according to this method, sterilization treatment of microorganisms such as bacteria, yeasts and molds can be performed at the same time.

 However, in a method of dissolving a supercritical fluid in a liquid food by supplying a supercritical fluid of carbon dioxide in a fine size through a filter, the carbon dioxide is not used in a dead-end type treatment tank. Insufficient disinfection and enzyme inactivation effects can be obtained because sufficient dissolution cannot be achieved. On the other hand, in the aeration type dissolution tank, although sufficient sterilization and enzyme deactivation effects can be obtained, there is a problem that fragrance components in liquid foods are extracted by supercritical carbon dioxide fluid (Journal of Food Science, 59). , 231-233 (1994)).

 The present inventors have further proposed a new continuous processing apparatus in order to perform such a sterilization treatment and an enzyme deactivation treatment more efficiently and without deterioration in quality (Japanese Patent Laid-Open No. 11-33008). No. 7 and Japanese Patent Application Laid-Open No. 9-1204604).

In the continuous apparatus described in JP-A-11-33087 and JP-A-9204044, liquid food is continuously supplied to the bottom of a processing tank maintained at a predetermined pressure and a predetermined temperature. While supplying supercritical carbon dioxide continuously through a mesh filter arranged at the bottom of the processing tank, and providing a liquid outlet near the top of the processing tank below the liquid level. Has been collected. In the treatment tank, the liquid food and the micro-bubble supercritical fluid come into contact with each other while flowing in parallel in the ascending direction, so that not only sterilization but also the enzyme can be efficiently deactivated. In addition, a supercritical fluid outlet is provided at the top of the processing tank, and the supercritical fluid can be taken out and returned to the carbon dioxide supply source for reuse. According to this device, liquid food can be processed continuously, Mass processing is possible.

 However, the methods for treating liquid foods described in JP-A-11-33087 and JP-A-9-206044 are supercritical (71 atm, 31 ° C or higher). ) Or subcritical (60 to 70 atm, 25 ° C or higher) carbon dioxide in microbubbles through a small-diameter filter and ejected into liquid foods, Although the dissolution efficiency can be improved, the dissolution and retention of carbon dioxide and the removal of dissolved carbon dioxide are performed in different places.

 Therefore, a high-pressure pump for sending liquid food is indispensable, which not only makes it difficult to increase the size and installation space of the equipment, but also uses a large amount of carbon dioxide and makes it difficult to recycle carbon dioxide. There is a problem that is. In addition, in this continuous treatment method, the flow rate and pressure control are extremely complicated, which leads to an increase in equipment costs and treatment costs, and lacks economy. Furthermore, in order to obtain a sufficient bactericidal and enzyme inactivating effect, the liquid food must be retained for a predetermined time in a state in which a sufficient amount of carbon dioxide has been dissolved. Needs to be determined.

 On the other hand, the sample treated by the above method contains carbon dioxide at a concentration that can be easily sensed by humans even after the atmospheric pressure is released. For this reason, before the above method is put to practical use, it is necessary to remove the carbon dioxide remaining in the product to a level that cannot be detected by humans before filling the liquid food into the container.

Therefore, an object of the present invention is to dissolve pressurized carbon dioxide in a liquid food without losing the scent of the liquid food, to efficiently sterilize the liquid food and deactivate enzymes, and to remove carbon dioxide. Provided is a liquid food processing method for efficiently removing carbon dioxide dissolved in a liquid food while suppressing foaming and loss of aroma components and the like of the liquid food, and an apparatus for performing the liquid food processing method And the small size of the device It is an object of the present invention to provide a liquid food processing apparatus capable of realizing cost saving by realizing a space saving by cost reduction. Disclosure of the invention

 The present inventors have conducted intensive studies to solve the above problems, and as a result, by agitating and circulating pressurized liquid, gas, and supercritical carbon dioxide introduced into the liquid food in the treatment tank into the liquid food, Dissolve the pressurized carbon dioxide almost to the saturation level without losing the scent of the liquid food, make the concentration of the dissolved pressurized carbon dioxide uniform throughout the treatment tank, and maintain that state for a predetermined time. Thus, sterilization and enzyme deactivation of liquid food can be efficiently performed. Then, after agitating and circulating the liquid food, the pressurized carbon dioxide is reduced to a predetermined pressure, and the remaining carbon dioxide is removed by an inert gas. By extracting and removing carbon, carbon dioxide can be removed while suppressing foaming due to carbon dioxide, and concentration polarization of aroma components and the like in liquid food can be suppressed. It found that it is possible to suppress the excessive loss of aroma components by, and have completed the present invention.

 That is, the present invention is specified by the following items [1] to [6].

[1] Pressurized carbon dioxide is introduced into a processing tank filled with liquid food, and the pressurized carbon dioxide is stirred and circulated into the liquid food in the processing tank to dissolve the carbon dioxide in the liquid food. And a first step of making the concentration of dissolved carbon dioxide in the liquid food uniform, deactivating enzymes contained in the liquid food while maintaining the concentration of dissolved carbon dioxide in the liquid food uniform, and / or The second step to maintain the conditions for killing, and, after discharging a part of the pressurized carbon dioxide, passing an inert gas through the liquid food and stirring and circulating the inert gas through the liquid food in the treatment tank. A method for treating a liquid food, comprising a third step of removing dissolved carbon dioxide. [2] After the first step, a step of heating the liquid food in which the pressurized carbon dioxide is dissolved is provided, and / or, after the second step, a step of cooling the liquid food in which the pressurized carbon dioxide is dissolved is provided. The method for treating a liquid food according to [1], characterized in that:

 [3] A liquid food processing apparatus having a gas inlet and a gas outlet, a liquid food inlet and a liquid food outlet, and having a built-in rotatable hollow shaft, wherein (1) the hollow shaft and the liquid shaft (2) The hollow shaft is provided with a carbon dioxide or inert gas inlet at an end thereof, and communicates with the hollow shaft at an arbitrary position on the hollow shaft. A gas dispersing device having a plurality of small holes for dispersing carbon dioxide or an inert gas formed by the above-described method is provided. Further, the hollow shaft is provided with a plurality of stirring blades communicating with or not communicating with the hollow shaft. An apparatus for treating liquid food, comprising:

 [4] The apparatus for treating a liquid food according to [3], further comprising means for heating or cooling the liquid food in the treatment tank.

 [5] The processing tank has a gas inlet and a gas outlet, a liquid food inlet and a liquid food outlet, and at least one baffle plate fixed to the inner wall of the processing tank, and has a built-in rotatable stirring shaft. (1) a contact portion between the stirring shaft and the treatment tank is formed in an airtight manner; and (2) the stirring shaft is provided in a vicinity of a liquid surface of the liquid food. An apparatus for treating liquid food, comprising a turbine-type stirring blade and at least one propeller-type stirring blade provided below the turbine-type stirring blade.

 [6] The apparatus for treating liquid food according to claim 5, wherein the treatment tank is provided with means for heating or cooling the liquid food. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a liquid food processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the gas generating unit according to Embodiment 1 of the present invention.

 FIG. 3 is a side view of the gas generating unit according to Embodiment 1 of the present invention.

 FIG. 4 shows a liquid food processing apparatus according to Embodiment 2 of the present invention.

 FIG. 5 shows a liquid food processing apparatus according to Embodiment 3 of the present invention.

 FIG. 6 is a graph showing the relationship between the temperature and pressure in dissolved pressure and the concentration of dissolved carbon dioxide in Example 1.

 FIG. 7 is a graph showing the relationship between the processing time and the survival rate in the second embodiment. FIG. 8 shows a conventional Dead-end type processing apparatus.

 FIG. 9 is a graph showing the relationship between the treatment time and the survival rate of yeast in Comparative Example 1.

 FIG. 10 shows a conventional ventilation type processing apparatus.

 FIG. 11 is a graph showing the relationship between the treatment time and the survival rate of yeast in Comparative Example 2.

 Fig. 12 shows a conventional aeration-type processing apparatus provided with stirring blades.

 FIG. 13 is a graph showing the relationship between the treatment time and the survival rate of yeast in Comparative Example 3.

 FIG. 14 shows a liquid food processing apparatus according to Embodiment 4 of the present invention. FIG. 15 is a graph showing the relationship between the treatment time and the survival rate of yeast in Example 3. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in detail.

In the method for treating a liquid food of the present invention, pressurized carbon dioxide is introduced into a treatment tank filled with the liquid food, and the pressurized carbon dioxide is stirred and circulated through the liquid food in the treatment tank. First step of dissolving carbon dioxide in liquid food and making the concentration of dissolved carbon dioxide in the liquid food uniform, the concentration of dissolved carbon dioxide in liquid food The second step of maintaining the conditions to inactivate enzymes contained in the liquid food and kill z or micro-organisms while maintaining the degree of uniformity, and after removing a part of pressurized carbon dioxide, Removing dissolved carbon dioxide by ventilating an inert gas through the process.

 In the first step of the treatment method of the present invention, the pressurized carbon dioxide introduced into the treatment tank filled with the liquid food is dissolved in the liquid food without losing the aroma of the liquid food, and It is important to make the concentration of dissolved carbon dioxide uniform, and for this purpose, the introduced pressurized carbon dioxide is agitated and circulated through the liquid food as microbubbles.

 In the second step of the treatment method of the present invention, it is important to maintain the concentration of dissolved carbon dioxide in the liquid food uniformly in all places in the treatment tank and to maintain the concentration for a predetermined time. Stir and circulate the liquid food in which pressurized carbon dioxide is dissolved without heating (30-65 ° C) or heating. By this step, the number of surviving bacteria can be reduced to at least 1 Z 1, 0000, 0000 or less in a normal sterilization step.

 In the third step of the treatment method of the present invention, in order to prevent liquid food from overflowing from the treatment tank, pressurized carbon dioxide is depressurized while suppressing foaming, and a part thereof is discharged. To form microbubbles, and the remaining carbon dioxide is extracted and removed into the microbubbles of the inert gas. In this step as well, it is important to stir and circulate the liquid food containing residual carbon dioxide and inert gas. As a result, the microbubbles of the inert gas are evenly dispersed in the liquid food, the polarization of the concentration of aroma components and the like in the liquid food is suppressed, and the carbon dioxide remaining in the liquid food is efficiently removed. At the same time, excessive loss of fragrance components and the like can be suppressed.

Thus, in all the steps of the method for treating liquid food of the present invention, it is important to agitate and circulate the liquid food together with microbubbles of pressurized carbon dioxide and inert gas. is there. The method of agitating and circulating the liquid food is not particularly limited. It is preferable to use the processing apparatus A or the liquid food processing apparatus B including a baffle plate fixed to the inner wall of the processing tank, a turbine-type stirring blade rotating in the processing tank, and a propeller-type stirring blade.

 The pressurized carbon dioxide in the present invention may be in a liquid, gas or supercritical state, and is preferably carbon dioxide in a state near the evaporation line in the phase diagram. Specifically, carbon dioxide having a temperature of 10 to 60 ° C, preferably 10 to 30 ° C, and a pressure of 20 to 300 atm, preferably 40 to 100 atm It is. Pressurized carbon dioxide must have a density lower than that of liquid food, but if the conditions above are appropriately selected, the density of pressurized carbon dioxide can easily be made smaller than the density of liquid food. Can be.

 The pressurized carbon dioxide in the present invention is supplied from a storage tank filled with liquefied carbon dioxide gas as a supply source, but may be supplied under pressure by a pump if necessary. Alternatively, the pressure can be increased to a predetermined pressure and stored in a storage tank, and this can be used as a direct supply source. The temperature of the liquid food can be monitored by a temperature sensor, and the pressure in the processing tank can be monitored by a pressure sensor. When the pressurized carbon dioxide is supplied directly from the pressure pump, the pressure in the processing tank is adjusted by controlling the pressure pump based on the output of the pressure sensor attached to the processing tank. When pressurized carbon dioxide is supplied from the pressurized carbon dioxide storage tank, the treatment tank does not require a pressure control valve.

 A liquid food processing apparatus A having a built-in hollow shaft provided with a gas dispersing apparatus having a gas suction port and a plurality of small holes and a stirring blade, which is suitable for performing the liquid food processing method of the present invention, is used. Then, the method for treating liquid food of the present invention will be described in more detail.

In processing unit A, a gas dispersing unit having a gas suction port and By rotating the hollow shaft provided with the stirring blades in the liquid food, a decompression portion was created at the tip of the gas dispersion device (gas generation unit), and as a result, it was protruded from the end of the hollow shaft. Pressurized carbon dioxide is sucked through the inside of the hollow shaft from the suction port, and the carbon dioxide can be made into microbubbles by the shearing force of the gas dispersing device to be dispersed in the radial direction of the treatment tank. The radial dispersion of pressurized carbon dioxide generated in this way is spread in the vertical direction in the radial direction by the stirring blades arranged on the hollow shaft, and the liquid food is circulated in the processing tank in the vertical direction. However, the bias of the concentration distribution of the dissolved carbon dioxide in the treatment tank can be eliminated, and the concentration distribution of the dissolved carbon dioxide can be made uniform in the treatment tank. Thereby, the pressurized carbon dioxide can be efficiently dissolved in the liquid food without losing the aroma of the liquid food.

 On the other hand, the concentration of dissolved carbon dioxide cannot be sufficiently increased in the processing tank of the Dead-end method. In the aeration-type treatment tank, the scent of liquid food is extracted by pressurized carbon dioxide and discharged from the treatment tank together with pressurized carbon dioxide, so that the fragrance of the liquid food is weakened. In a sparger-type treatment tank, pressurized carbon dioxide and an inert gas must be supplied into the liquid food, but in this case, the treatment of the liquid food that has entered the inside of the concave portion of the supply port is improper. It is feared that it will be sufficient. This is the same in a treatment tank system in which pressurized carbon dioxide is circulated externally.

The amount (volume) of pressurized carbon dioxide that comes into contact with the liquid food is determined by the carbon dioxide suction power generated by rotating the hollow shaft and rotating the carbon dioxide gas generator. Although it depends on the size and shape of the processing tank, the carbon dioxide suction capacity is preferably ^{4 to 2} Om ³ h as the volume of pressurized carbon dioxide per lm ³ of the processing tank. Here, as the suction capacity is less than 4 m ³ Zh, dissolution rate of carbon dioxide into the liquid food is reduced, the time required for dissolving carbon dioxide process tended to be longer, larger than 2 0 m ³ Zh Introducing pressurized carbon dioxide to increase the hold-up volume of liquid food in the treatment tank It becomes necessary to increase the space above the processing tank.

 The number of revolutions when rotating the gas generating section or the stirring blade around the hollow shaft depends on the diameter of the gas generating section and the type of liquid food to be processed. For example, in the case of orange juice, 100 to 60 0 rpm is preferred. Here, if the rotation speed is less than 100 rpm, the amount of pressurized carbon dioxide or microbubbles of inert gas in the liquid food becomes insufficient, and the dissolution of carbon dioxide in the first step is prolonged. Not only does it take time, but the efficiency of removing the remaining carbon dioxide in the third step is reduced. Furthermore, since the vertical circulation of the liquid food by the stirring blade is reduced, it tends to be difficult to suppress the concentration polarization of volatile components such as aroma components. On the other hand, if the rotation speed exceeds 600 rpm, the hold-up volume of the liquid food tends to be excessively increased due to excessive generation of microbubbles of pressurized carbon dioxide. In addition, extra power consumption and deterioration of sealing means such as a mechanical seal for rotating the hollow shaft in a sealed state are hastened.

 After dissolving the pressurized carbon dioxide, making the dissolved carbon dioxide concentration in the liquid food uniform in all places in the treatment tank can deactivate the enzymes contained in the liquid food in the second step and / or It is extremely important in the process of killing microorganisms (sterilization process). In other words, in the normal sterilization process, it is necessary to reduce the number of surviving bacteria to at least 11, 000, 0000 or less. To achieve this, the dissolved carbon dioxide is diffused evenly to the vicinity of the treatment tank wall. It is necessary to make it. Thus, in order to disperse the dissolved carbon dioxide concentration as uniformly as possible up to the vicinity of the processing tank wall, the liquid entrainment effect due to the rise of the microbubbles of pressurized carbon dioxide generated at the bottom of the processing tank, etc. Based agitation is not sufficient.

To this end, it is important to provide an effective stirring blade on the hollow shaft, depending on the size, shape and material of the treatment tank and the type of liquid food. Specifically, it is effective to use a propeller type stirring blade, a turbine type stirring blade, or a combination thereof. The liquid food is stirred by stirring the liquid food with stirring blades. The product can be circulated in the vertical direction, and the concentration of dissolved carbon dioxide in the liquid food can be made uniform at all places in the treatment tank. The rotation speed of these stirring blades is 60 r ρ π! ~ 600 rpm is preferred. Here, as the stirring speed becomes lower than 60 rpm, there is a tendency that the diffusion of dissolved carbon dioxide near the wall of the treatment tank decreases, and the disinfection effect tends to decrease. On the other hand, as the rotation speed exceeds 600 rpm, the power consumption increases and the deterioration of the sealing means of the hollow shaft tends to accelerate.

 With the pressurized carbon dioxide in the present invention, the carbon dioxide discharged from the treatment tank is further pressurized, and the carbon dioxide liquefied and cooled and stored in the storage tank can be reused as necessary. At this time, it is also possible to separate and remove unnecessary volatile components. The gas, liquid, or supercritical state can be directly reused without special pressure adjustment, heating, or cooling.

 In order to reuse pressurized carbon dioxide, it is possible to directly reuse pressurized carbon dioxide by arranging a plurality of processing tanks and providing a time lag between the processing steps performed in each processing tank. In other words, it is possible to move directly from the preceding treatment tank, which has completed the step of holding the dissolved carbon dioxide under pressure, to the upper space of the next treatment tank filled with a certain amount of liquid food via the pressurized carbon dioxide outlet. it can. This operation recycles about 50% of the carbon dioxide. In order to further increase the recycling rate, it is necessary to transfer carbon dioxide via a pressurized pump. The logarithm of the rate of liquid food sterilization and enzyme deactivation increases linearly with the liquid food processing temperature and dissolved carbon dioxide (dissolved carbon dioxide) concentration. Therefore, after dissolving the pressurized carbon dioxide, the temperature of the liquid food is raised to a predetermined level and maintained for a predetermined time, whereby the microorganisms in the liquid food can be surely killed.

Specifically, by raising the temperature of the liquid food in which pressurized carbon dioxide is dissolved from 10 to 30 ° C to 30 to 65 ° C while the treatment tank is sealed, the inside of the treatment tank ( Pressurized carbon dioxide) can be raised from 30 to 80 &1; 111 to 50 to 300 & tm, and it is preferable to keep the pressure as it is for 3 to 60 minutes. However, these conditions are appropriately changed depending on the type of liquid food. Here, as the pressure of pressurized carbon dioxide becomes higher than 300 atm, it tends to require a lot of cost to increase the pressure resistance of the treatment tank, and as the pressure becomes lower than 50 atm, sterilization becomes more likely. The effect tends to be smaller. In addition, the quality of the liquid food tends to decrease as the temperature of the heated liquid food rises above 65 ° C, and the sterilizing effect tends to become insufficient as the temperature falls below 30 ° C. Is seen. In addition, the number of surviving bacteria tends to increase as the holding time is shorter than 3 minutes, and the treatment efficiency tends to decrease as the holding time is longer than 60 minutes.

 After the liquid food in which carbon dioxide is dissolved is held for a predetermined time, a step of reducing the pressure of the pressurized carbon dioxide is performed. Although the pressure after the pressure reduction is not particularly limited, it is 1 atm (atmospheric pressure) to 20 atm, preferably 5 to 10 atm. Here, as the pressure becomes lower than 5 atm, foaming during decompression increases, and in order to prevent liquid food from overflowing from the processing tank during decompression, the upper gap when filling the processing tank with liquid food is required. Need to be kept large. If the pressure after discharging the pressurized carbon dioxide is higher than 10 atm, the amount (mass) of the inert gas used to remove the dissolved carbon dioxide tends to increase. Can be seen.

As the inert gas used in the present invention, other than nitrogen, argon, helium and the like can be used as long as they are safe without toxicity and are inert to liquid foods. Means for generating the inert gas include, but are not limited to, compression tanks (high-pressure storage tanks), liquefaction tanks, and those obtained by separating nitrogen in the atmosphere at the site. Here, as a method for separating nitrogen in the atmosphere, a PSA method (Pressure swing adsorption method) or the like is used. In addition, inert gas It is preferable to ventilate the cells.

 By extracting the dissolved carbon dioxide into the microbubbles of the inert gas, the dissolved carbon dioxide can be removed. That is, while the microbubbles of the inert gas are being stirred in the liquid food, the dissolved carbon dioxide molecules diffuse into the microbubbles according to Henry's law, are taken into the microbubbles, and become incompatible with the carbon dioxide. The enlarged bubbles composed of the active gas mixture collapse on the liquid level in the treatment tank, and the carbon dioxide is discharged out of the system together with the inert gas. Further, in the step of passing an inert gas into the liquid food, it is possible to suppress concentration polarization of aroma components and the like generated in the liquid food. Specifically, microbubbles of inert gas are generated in the liquid food, and the upflow and downflow can be generated more effectively by using a stirring blade. Can be made uniform. In this case, by providing a partition wall in the treatment tank containing the liquid food, the ascending flow and the descending flow can be generated even more effectively.

Since the liquid food that is being treated with pressurized carbon dioxide contains 10 to 30 times the volume of carbon dioxide (converted to standard conditions) compared to the liquid food, if the pressure is reduced as it is after the treatment, Intense foaming occurs in liquid food, and a large amount of liquid food overflows from the treatment tank filled with liquid food. In other words, even if a high concentration of dissolved carbon dioxide is contained under pressure, foaming in liquid food caused by depressurization is slight up to 5 to 10 atm, but the pressure is low. As the temperature increases, the foaming of dissolved carbon dioxide increases. The reason is that even if the amount (mass) of carbon dioxide emitted per unit time under pressure is large, it is removed in a compressed state, so the volume of carbon dioxide separated from liquid food is small. is there. On the other hand, in the depressurization operation at 5 atm or less, the compression rate in the treatment tank is low even if the amount of carbon dioxide removed per unit time is small, Intense foaming occurs in the interior. In order to avoid violent bubbling of carbon dioxide in liquid foods, the pressure is reduced by directly discharging carbon dioxide from the processing tank up to the processing pressure of 5 to 10 atm, and after that, it is not pressurized. It is preferable to carry out aeration and agitation of microbubbles of the active gas. In other words, when the pressure is 5 to 10 atm or less, the dissolved carbon dioxide can be removed by extracting the dissolved carbon dioxide with an inert gas without expanding, while suppressing foaming. The reason is that the inert gas (nitrogen) has a solubility in an aqueous solution that is almost 1/25 that of carbon dioxide, so that the liquid food from which carbon dioxide is separated does not show any foaming properties.

 Under these circumstances, the supply pressure of the inert gas is determined in consideration of the following factors.

 1) As the pressure of the inert gas increases, the contact area with the liquid food decreases, and the extraction rate of dissolved carbon dioxide decreases. 2) The higher the pressure of the inert gas, the larger the amount (mass) of the inert gas required to extract the dissolved gas. 3) Operation at higher pressure than necessary is disadvantageous because a compressor for increasing pressure is required. 4) If the pressure of the inert gas is too low, in the operation of discharging carbon dioxide up to that pressure, the liquid food will foam and overflow from the treatment tank.

Considering the above points, for liquid foods that contain high concentrations of dissolved carbon dioxide under pressure, the dissolved carbon dioxide can be separated by depressurization without ventilating inert gas from 5 to 10 atm. After the pressure of the liquid food drops to about 5 to 10 atm, it is preferable to extract and separate dissolved carbon dioxide by passing an inert gas pressurized to the same degree. At this time, the pressure of the inert gas supplied along with the removal of the dissolved carbon dioxide can be reduced. Means for heating or cooling liquid foods ・ As a method, one or more coils with heating and cooling media inserted inside the treatment tank and inside the treatment tank are covered, and between the treatment tank and Jacket with heating / cooling medium inserted, inside processing tank Heating / cooling method using one or more plate-type heat exchangers and the like arranged in the above, but is not limited thereto. Water, steam, oil, or the like is used as the heating / cooling medium.

 In the processing apparatus B suitable for performing the processing method of the present invention, a baffle plate fixed to the inner wall surface of the processing tank, a one-bottle type stirring blade provided near the liquid surface, and a lower part thereof are provided below. By rotating the propeller-type stirring blade in the treatment tank, the introduced pressurized carbon dioxide or inert gas and the liquid food are efficiently mixed, and the concentration of pressurized carbon dioxide or inert gas in the treatment tank is reduced. It can be uniform at all positions. That is, a large number of air bubbles can be generated near the liquid surface by stirring with the evening bottle type stirring blade provided near the liquid surface and the baffle plate fixed to the processing tank. By the flow in the direction of the stirring axis caused by the provided propeller-type stirring blade, bubbles near the liquid surface can be circulated and mixed to the lower part of the processing tank. As a result, similarly to the processing apparatus 1 described above, the carbon dioxide can be efficiently dissolved uniformly in the liquid food, and the dissolved carbon dioxide can be removed by the inert gas without impairing the aroma of the liquid food. be able to.

 The position of the turbine type stirring blade is provided near the liquid surface, and the position can vary depending on the volume of the processing tank, the diameter of the stirring blade, the rotation speed, and the like. It is arranged to generate active gas below the liquid surface as fine bubbles.

The baffle plate will be installed at the same depth as the turbine type stirring blade. Thus, the circular motion caused by the rotational motion of the turbine-type stirring blade is suppressed by the baffle plate, and bubbles can be effectively generated near the tip of the turbine-type stirring blade. Liquid foods to which the present invention is applied include vegetable juice, fruit juice, coffee, black tea, green tea, oolong tea, cocoa, beer, sugar, milk, cream and other sweeteners, and various beverages to which other additives are added, Milk, processed milk, fermented milk, milk Examples include, but are not limited to, beverages, wine, sake, soy sauce, mentsuyu, mirin, vinegar, and nutrient drinks.

 Hereinafter, a liquid food processing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

 (Embodiment 1)

 FIG. 1 is a schematic diagram of a liquid food processing apparatus according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a gas generator, and FIG. 3 is a side view of the gas generator.

In the figure, 1 is a liquid food processing apparatus according to the present embodiment, 2 is a cylindrical processing tank made of pressure-resistant stainless steel that stores liquid food, 3 is a liquid food stored in a processing tank 2, and 4 is a liquid food. A stainless steel hollow shaft that is formed rotatably at the approximate center of the processing tank 2 and allows pressurized carbon dioxide or inert gas to pass through inside. 5 is a portion that communicates with the hollow shaft 4 and agitates the liquid food in the axial direction. A stainless steel gas generator with a number of small holes in the donut-shaped outer surface supported by a lateral communication pipe with a large gap so that it is not blocked, 6 was disposed on the hollow shaft 4, Stainless steel agitating blade for stirring liquid food, 7 is protruded from the end of hollow shaft 4 above the liquid level of liquid food in processing tank 2 and suction to suck pressurized carbon dioxide or inert gas The hole 8 is in the contact area between the hollow shaft 4 penetrating into the treatment tank 2 and the treatment tank 2. The formed magnetic drive as a means for sealing the inside of the processing tank 2, and 9 is a gas inlet formed above the processing tank 2 for introducing pressurized carbon dioxide or inert gas into the processing tank 2. , 10 is a gas outlet formed above the processing tank 2 for discharging pressurized carbon dioxide or inert gas from the processing tank 2 to the outside, 11 is a pressure regulating valve for reducing the carbon dioxide in the processing tank 2 Reference numeral 12 denotes a motor fixed to the upper end of the hollow shaft 4 and serves as a driving unit for rotating the hollow shaft 4. Reference numeral 13 denotes a motor formed at the lower side of the processing tank 2 for introducing liquid food into the processing tank 2. A food inlet 14 is a food outlet formed in the lower side of the processing tank 2 for discharging liquid food to the outside. In addition, a thermometer and pressure sensor required to adjust the temperature and pressure in the processing tank 2 It is also possible to provide a sensor or the like. By these adjustments, a sufficient bactericidal effect can be exhibited in the treatment tank 2. Here, as the liquid food processing apparatus 1, a stirred tank reactor (manufactured by BIAZZI) having a hollow shaft provided with a stirring blade can be used.

Here, examples of the material of the treatment tank 2 include stainless steel, iron and steel, various types of reinforced plastics, and composite materials thereof, but are not limited thereto. The size of the processing tank 2, depending on the liquid food manufacturing scale, 0.. 5 to 2 0 m ³ is preferred. Here, as the volume becomes larger than 2 Om ³ , there is a tendency that the manufacturing cost of the treatment tank 2 having pressure resistance tends to increase significantly. In such cases, it is advantageous to the processing tank 2 having a volume of several m ³ multiple installation. Examples of the shape of the treatment tank 2 include a cylindrical shape and a polygonal shape, but are not particularly limited.

The hollow shaft 4 used in the present invention is rotatably formed at a substantially central portion in the treatment tank 2, and a suction hole 7 through which pressurized carbon dioxide or an inert gas is sucked is provided at an end of the hollow shaft 4. Have been. Examples of the material of the hollow shaft 4 include, but are not limited to, stainless steel and steel. The protruding position of the suction hole 7 is advantageous because the larger the distance from the liquid surface when the liquid food is filled, the larger the hold-up volume per suction volume of pressurized carbon dioxide or inert gas can be set. . However, its shape and size are not particularly limited. The shape of the gas generating section 5 of pressurized carbon dioxide or inert gas is not particularly limited, but a large gap is provided at the portion communicating with the hollow shaft 4 so that the stirring of the liquid food in the axial direction is not interrupted. It is preferable that a number of small holes are provided in the donut-shaped outer surface supported by the provided lateral communication pipe. The size of such small holes efficiently generates fine bubbles of pressurized carbon dioxide and inert gas, but an excessively small hole size is not preferable in consideration of the ease of cleaning of the apparatus with a chemical solution or the like. Examples of the material of the gas generating section 5 include stainless steel and steel. But not limited to these.

 The stirring blade 6 used in the present invention is disposed on the hollow shaft 4, and specifically includes a propeller stirring blade, a turbine stirring blade, and the like, but is not limited thereto. The use of the stirring blade 6 mainly causes an axial flow to efficiently contact the liquid food with the pressurized carbon dioxide to promote its dissolution. In addition, the dissolved carbon dioxide can be uniformly diffused to the vicinity of the processing tank wall, and at the same time, the adsorption of microorganisms and the like to the wall surface inside the processing tank 2 can be suppressed, and the sterilization efficiency can be improved. In addition, heat exchange can be promoted.

 As a means for sealing the inside of the processing tank 2 of the present invention, in addition to the magnetic drive 8, a ground type or a mechanical seal or the like is used, but is not limited thereto.

 The drive unit for rotating the hollow shaft 4 in the present invention is not particularly limited, but a motor 12 or the like is used.

 The processing method using the liquid food processing apparatus according to the first embodiment will be described below.

 The liquid food 3 is introduced from the food inlet 13 in the liquid food processing apparatus according to the first embodiment, and the hollow shaft 4 in the processing tank 2 is rotated by operating the motor 12.

 Pressurized carbon dioxide is introduced into the treatment tank 2 from the gas inlet 9 and sucked into the hollow shaft 4 from the suction hole 7, and pressurized carbon dioxide is generated in the liquid food 3 from the gas generator 5. At the same time, the stirring blade 6 is rotated around the hollow shaft 4 to bring the pressurized carbon dioxide into sufficient contact with the liquid food 3 to dissolve the pressurized carbon dioxide in the liquid food 3, and to dissolve the dissolved pressurized carbon dioxide. Make the concentration uniform.

Next, the gas inlet 9 is closed, the temperature of the liquid food 3 is kept at room temperature, and the pressure in the processing tank 2 is maintained at 70 to 150 atm for 5 to 30 minutes, so that the liquid food 3 is introduced into the liquid food 3. Deactivates the enzymes involved and kills microorganisms. Thereafter, the carbon dioxide in the treatment tank 2 is gradually discharged from the pressure regulating valve 11, and when the pressure in the treatment tank 2 decreases to 5 to 10 atm, a compression cylinder (not shown) is used. Nitrogen gas, which is an inert gas, is introduced from the gas inlet 9, is sucked into the hollow shaft 4 from the suction hole 7, and nitrogen gas microbubbles are generated in the liquid food 3 from the gas generator 5. The liquid food 3 thus treated is discharged out of the treatment tank 2 from the food outlet 14.

 The following effects are obtained by performing the processing method using the liquid food processing apparatus in the first embodiment.

 Since a circulating treatment tank is used, carbon dioxide can be dissolved more efficiently than a non-circulation treatment tank (Dead-end method) or a vented treatment tank, and the amount of carbon dioxide used And the recycling of carbon dioxide is easy, and the loss of aroma components can be minimized.

 By stirring the liquid food in the processing tank, the concentration of dissolved carbon dioxide in the processing tank and the temperature of the liquid food can be kept constant. Furthermore, adsorption of microorganisms on the wall surface in the treatment tank can be suppressed, and high sterilization efficiency can be obtained.

 Filling of liquid foods ・ Dissolution of carbon dioxide ・ Temperature control of liquid foods ・ Removal of dissolved carbon dioxide is carried out in the same processing tank at different times, so it is necessary to install a high-pressure pump for sending liquid foods And space saving can be realized. Further, the range of setting various conditions is wide, and the residence time can be set regardless of the processing speed in the batch processing of the present invention. That is, by increasing the residence time, a sufficient sterilizing effect can be obtained even at a low sterilizing temperature. Furthermore, since only the pressure in the processing tank is controlled and flow rate control is not required, system control is easy, safety is excellent, and an energy-saving system can be realized.

After efficient sterilization of liquid food using pressurized carbon dioxide, Prior to filling food containers, carbon dioxide contained at concentrations easily perceived by humans in the treatment tank can be removed to levels that are not perceived by humans.

 (Embodiment 2)

 FIG. 4 is a schematic diagram of a liquid food processing apparatus according to Embodiment 2 of the present invention.

 In the figure, 1a is a liquid food processing apparatus according to the present embodiment, 2a is a pressure-resistant stainless steel cylindrical processing tank for storing liquid food, 3a is a liquid food stored in the processing tank 2a, 4a is a rotatable shaft formed approximately in the center of the processing tank 2a, and a stainless steel hollow shaft through which pressurized carbon dioxide or inert gas passes.5a is a liquid that communicates with the hollow shaft 4a. Stainless steel gas generator with a number of small holes on the donut-shaped outer surface supported by a horizontal communication pipe with a large gap so that the axial stirring of food is not interrupted, 6a is a hollow shaft 4a, a stainless steel stirring blade for agitating liquid food, 7a is protruded from the end of the hollow shaft 4a above the liquid level of the liquid food in the treatment tank 2a, and pressurized dioxide Suction hole for sucking carbon or inert gas, 8a is hollow shaft 4a passing through processing tank 2a Magnetic drive as a means for sealing the inside of the processing tank 2a formed at the contact part with the processing tank 2a, 9a is formed above the processing tank 2a, and pressurized in the processing tank 2a Gas inlet for introducing pressurized carbon dioxide or inert gas, 10a is formed above treatment tank 2a, and gas for discharging pressurized carbon dioxide or inert gas from processing tank 2a to the outside Discharge port, 1 a is a pressure regulating valve for reducing the carbon dioxide in the processing tank 2 a, and 12 a is a hollow shaft fixed to the upper end of the hollow shaft 4 a

A motor as a drive unit for rotating 4a, 13a is formed on the lower side of processing tank 2a, and a food inlet for introducing liquid food into processing tank 2a, 14a is processing tank 2 a food outlet formed on the lower side of a to discharge liquid food to the outside, 1

5a is a heating or cooling coil arranged in the processing tank 2a. The processing It is also possible to provide a thermometer, a pressure sensor, and the like necessary for adjusting the temperature and pressure in the tank 2a. By these adjustments, a sufficient bactericidal effect can be exhibited in the treatment tank 2a. Here, for the liquid food processing apparatus 1a, a stirred tank reactor (manufactured by BIAZZI) having a hollow shaft equipped with stirring blades can be used.

 A processing method using the liquid food processing apparatus 1a according to the present embodiment will be described below.

 Liquid food 3a is introduced from the food inlet 13a of the liquid food processing apparatus 1a, and the hollow shaft 4a in the processing tank 2a is operated and rotated by the motor 12a. Pressurized carbon dioxide is introduced into the treatment tank 2a from the gas inlet 9a and is sucked into the hollow shaft 4a from the suction hole 7a, and pressurized carbon dioxide is supplied from the gas generator 5a to the liquid food 3. a, while rotating the stirring blade 6a around the hollow shaft 4a to bring the pressurized carbon dioxide into sufficient contact with the liquid food 3a to dissolve the pressurized carbon dioxide in the liquid food 3a. Make the concentration of dissolved pressurized carbon dioxide uniform. Next, the gas inlet 9a is closed, a heating medium (hot water 60 ° C) is supplied, and the temperature of the liquid food 3a is raised to 35 to 40 ° (: the pressure in the processing tank 2a is reduced to 70 to 40 ° C). By maintaining at 150 atm for 5 to 30 minutes, the enzymes contained in the liquid food 3a are inactivated, and the microorganisms are killed.

 After that, while supplying a cooling medium (cooling water at 10 ° C), the temperature is lowered to 25 to 30 ° C, and the carbon dioxide in the treatment layer 2 a is gradually discharged from the pressure regulating valve 11 a. When the pressure in the processing tank 2a drops to 5 to 10 atm, nitrogen gas, which is an inert gas, is introduced from the gas inlet 9a using a compression cylinder (not shown), and the suction hole 7a Then, the liquid is sucked into the hollow shaft 4a, and micro gas bubbles of nitrogen gas are generated in the liquid food 3a from the gas generator 5a. The liquid food 3a thus treated is discharged from the treatment outlet 2a from the food discharge port 14a.

In the present embodiment, in addition to the effects obtained in Embodiment 1, liquid food By heating the liquid food after dissolving the pressurized carbon dioxide therein, the sterilizing effect can be further increased without lowering the dissolved carbon dioxide concentration. Further, since a plurality of coils are arranged in the processing tank, the thermal efficiency can be improved.

 (Embodiment 3)

FIG. 5 is a schematic diagram of a liquid food processing apparatus according to Embodiment 3 of the present invention. In the figure, 1b is a liquid food processing apparatus according to the present embodiment, 2b is a pressure-resistant stainless steel cylindrical processing tank for storing liquid food, 3b is a liquid food stored in processing tank 2b, 4b is a stainless steel hollow shaft that is rotatably formed at the approximate center of the processing tank 2b and allows pressurized carbon dioxide or inert gas to pass through it.5b is a liquid that communicates with the hollow shaft 4b. Stainless steel gas generator with a number of small holes on the donut-shaped outer surface supported by a horizontal communication pipe with a large gap so that the axial stirring of food is not interrupted, 6b is a hollow shaft 4b, a stainless steel stirring blade for stirring liquid food, 7b is protruded from the end of the hollow shaft 4b above the liquid level of the liquid food in the treatment tank 2b, and pressurized dioxide Suction hole for sucking carbon or inert gas, 8 b is hollow shaft inserted into treatment tank 2 b 4 b Magnetic drive as a means for sealing the inside of the processing tank 2b formed at the contact part with the processing tank 2b, 9b is formed above the processing tank 2b and pressurized in the processing tank 2b A gas inlet for introducing pressurized carbon dioxide or inert gas, 10b is formed above the processing tank 2b, and is a gas for discharging pressurized carbon dioxide or inert gas from the processing tank 2b to the outside. Outlet, 11 b is a pressure regulating valve for reducing the carbon dioxide in the processing tank 2 b, 12 b is a motor fixed to the upper end of the hollow shaft 4 b and serves as a drive unit for rotating the hollow shaft 4 b, 13 b is formed in the lower side of processing tank 2b, and is a food inlet for introducing liquid food into processing tank 2b, and 14b is formed in the lower side of processing tank 2b, and allows liquid food to the outside. A food outlet 17b for discharging is a heating or cooling jacket provided on the outer surface of the processing tank 2b. In addition, it is also possible to provide a thermometer, a pressure sensor, and the like necessary for adjusting the temperature and pressure in the processing tank 2b. By these adjustments, a sufficient bactericidal effect can be exhibited in the treatment tank 2b. Here, for the liquid food processing apparatus lb, a stirred tank reactor (manufactured by BIAZZI) having a hollow shaft equipped with stirring blades can be used.

 Further, the method for treating liquid food is the same as that in Embodiment 2, and therefore the description is omitted.

 According to the present embodiment, the heating time of the liquid food can be shortened as compared with the method of introducing the pre-heated liquid food into the processing tank (the method without a heating device). Quality degradation can be minimized. Also, a pump with a lower pressure specification can be used as a pump for sending liquid carbon dioxide. Further, since the pressurized carbon dioxide is dissolved in the liquid food at a low temperature, the dissolution rate of the carbon dioxide can be increased.

 (Embodiment 4)

 FIG. 14 is a schematic diagram of a liquid food processing apparatus according to Embodiment 4 of the present invention.

In FIGS. 14 and 14, 1 c is a liquid food processing apparatus according to the present embodiment, 2 c is a cylindrical processing tank made of pressure-resistant stainless steel for storing liquid food, and 3 c is stored in processing tank 2 c 37 is a stirring shaft rotatably formed substantially at the center of the processing tank 2c, and 38 is a stirrer that generates a large number of bubbles from the introduced pressurized carbon dioxide or inert gas. A stainless steel evening bin type stirring blade disposed near the liquid surface of shaft 37, 39 is a stainless steel propeller type stirring blade for stirring liquid food disposed on stirring shaft 37, 4 0 is a baffle plate fixed to the inner wall surface of the processing tank 2c, and 8c is a processing tank 2c formed at a contact portion between the stirring shaft 37 inserted into the processing tank 2c and the processing tank 2c. A magnetic drive as a means for sealing the inside, 12 c rotates the stirring shaft 37 fixed to the upper end of the stirring shaft 37 As a driving unit, 9 c is formed above the processing tank 2 c, a gas inlet for introducing pressurized carbon dioxide or inert gas into the processing tank 2 c, and 10 c is a processing tank. A gas outlet formed above 2 c to discharge pressurized carbon dioxide or inert gas from the treatment tank 2 c to the outside, 1 1 c is a pressure regulating valve for reducing the carbon dioxide in the treatment tank 2 c, 1 2 c is a motor fixed to the upper end of the stirring shaft 37 and serves as a drive unit for rotating the stirring shaft 37, and 13 c is formed on the lower side of the treatment tank 2 c to process liquid foods A food introduction port for introducing into the tank 2c, and a food outlet 14c formed on the lower side of the treatment tank 2c for discharging liquid food to the outside. In addition, the processing apparatus 1c of the present embodiment includes a heating or cooling jacket (not shown) provided on the outer surface of the processing tank 2c or a heating or cooling jacket disposed in the processing tank 2c. A recirculating coil (not shown) can be provided. In addition, it is also possible to provide a thermometer, a pressure sensor, and the like necessary for adjusting the temperature and pressure in the processing tank 2c. By these adjustments, a sufficient bactericidal effect can be exhibited in the treatment tank 2c.

 Since the turbine-type stirring blade 38 in the present embodiment is disposed near the liquid surface of the liquid food 3c on the stirring shaft 37, the introduced pressurized carbon dioxide is combined with the operation of the baffle plate 40. Alternatively, many bubbles of inert gas can be generated near the liquid surface, and nearby bubbles are processed by the flow in the direction of the stirring shaft 37 caused by the propeller-type stirring blades 39 disposed deep in the processing tank. It can be circulated and mixed deep into the tank 2c.

 A processing method using the liquid food processing apparatus 1c according to the present embodiment will be described below.

The liquid food 3c is introduced from the food introduction port 13 of the liquid food processing apparatus 1c, and the stirring shaft 37 in the processing tank 2c is operated and rotated by the motor 12c. Pressurized carbon dioxide is introduced into the processing tank 2c from the gas inlet 9c, and a number of bubbles are generated near the liquid surface by the stirring of the turbine-type stirring blade 38 and the baffle plate 40. Next, the bubbles in the direction of the stirring shaft 37 caused by the propeller-type stirring blades 39 are circulated to circulate nearby bubbles deep into the treatment tank 2c, and the pressurized carbon dioxide is brought into sufficient contact with the liquid food 3c, and Dissolve pressurized carbon dioxide in food 3c and equalize the concentration of dissolved pressurized carbon dioxide.

 Next, the gas inlet 9c is closed, the temperature of the liquid food 3c is kept at room temperature, and the pressure in the processing tank 2c is maintained at 70 to 150 atm for 5 to 30 minutes, whereby the liquid food 3 is obtained. Deactivates enzymes contained in c and kills microorganisms.

 Thereafter, the carbon dioxide in the treatment bed 2c is gradually discharged from the pressure regulating valve 11c, and when the pressure in the treatment tank 2c falls to 5 to 10 atm, a compression cylinder (not shown) is opened. Nitrogen gas, which is an inert gas, was introduced from the gas inlet 9c, and a number of bubbles of nitrogen gas were generated near the liquid surface by the stirring of the turbine-type stirring blade 38 and the baffle plate 40. Next, by flowing in the direction of the stirring shaft 37 caused by the propeller-type stirring blade 39, nearby bubbles are circulated deep into the treatment tank 2c, and dissolved carbon dioxide gas is extracted into the nitrogen gas bubbles. Remove from gas outlet 10c. The liquid food 3c thus treated is discharged out of the treatment tank 2c from the food discharge port 14c.

 The processing method using the liquid food processing apparatus according to the fourth embodiment has the same operation as that of the first embodiment. Example

 Hereinafter, the present invention will be described in more detail by way of examples.However, these examples are merely examples, and do not limit the present invention, and may be modified without departing from the scope of the present invention. Good.

Example 1

In this example, the concentration of dissolved carbon dioxide at each temperature was measured using the device according to the third embodiment of the present invention. About 10% of the head space of the processing tank volume yeast O range juice added (Saccharomvces cerevisiae) a 1 m 1 per 10 ⁶ or more (25) from the food inlet into the treatment tank of the atmospheric pressure (250 meters l vol) Filled leaving. At this time, water at 25 ° C was circulated through the jacket of the treatment tank.

 Then, pressurized carbon dioxide (50 atm) was introduced into the void from the gas inlet, and the hollow shaft was rotated at 600 rpm to cause microbubbles of pressurized carbon dioxide in the orange juice. And began to dissolve carbon dioxide. After 5 minutes while rotating the hollow shaft, a part of the orange juice was withdrawn from the food outlet below the treatment tank, and the volume of carbon dioxide and juice generated therefrom was used to determine the partial pressure of steam at that temperature. The dissolved carbon dioxide concentration was calculated by correcting the solubility of carbon dioxide under atmospheric pressure. The same operation was performed by introducing lOOatm and 150 atm of pressurized carbon dioxide.

 Next, the temperature of the jacket circulating water was changed to 40 ° C., 50 ° C., and 75 ° C., and the same operation was performed for 50, 100, and 150 atm carbon dioxide. Figure 6 shows the results.

 Assuming that the pressure of carbon dioxide is constant, the solubility of carbon dioxide increases as the juice temperature decreases, and decreases as the temperature increases.Therefore, it is necessary to dissolve the carbon dioxide in a liquid food at a low temperature and then heat it. As a result, it was possible to achieve a state of high sterilizing power.

 In this example, 50 atm of carbon dioxide was dissolved in fruit juice at 25 ° C and heated to 40 ° C, so that the pressure in the treatment tank became 100 atm. This is the same state as dissolving 100 atm of carbon dioxide in juice at 40 ° C.

Similarly, when 50 atm of carbon dioxide is dissolved in fruit juice at 25 ° C and then heated to 50, the pressure in the treatment tank rises to 150 atm. This means that 150 atm of pressurized carbon dioxide was dissolved in juice that had been heated to 50 ° C in advance. It is the same state as when.

 Therefore, the method of dissolving carbon dioxide at low temperature and then heating contributes to lowering the supply pressure of carbon dioxide. At this time, if the dissolution of carbon dioxide at low temperatures is insufficient, it can be seen that the pressure rise due to subsequent heating becomes small. In other words, if the initial dissolution of carbon dioxide is not sufficient, a larger heating width is required to obtain the same bactericidal mosquito, which leads to a decrease in juice quality. Example 2

 In this example, the mortality of the yeast (Saccharomvces cerevisiae) was determined using the treatment apparatus of the third embodiment of the present invention.

About the treatment tank volume yeast O range juice added (Saccharomvces cerevisiae) a 1 m 1 per 0 ⁶ or more (2 5 ° C) from the food inlet into the treatment tank of the atmospheric pressure (2 5 0 ml vol) Filling was done leaving a 10% top void. At this time, water at 25 ° C was circulated through the jacket of the treatment tank.

 Then, pressurized carbon dioxide (50 atm) was introduced into the void from the gas inlet, and the hollow shaft was rotated at 600 rpm to reduce microbubbles of pressurized carbon dioxide into orange juice. And started to dissolve carbon dioxide. After 5 minutes while rotating the hollow shaft, a part of the orange juice was extracted from the food outlet below the treatment tank, and the dissolved carbon dioxide concentration reached about 1.2 M. In the description, M represents mo1Z1.

Next, the inside of the treatment tank was sealed, the hollow shaft was kept rotating, and warm water of about 55 ° C was circulated through the jacket of the treatment tank to heat the orange juice to 40 ° C. At this time, the pressure inside the processing tank rose to 100 atm. After reaching 100 atm, 0, 5, 10, 20 and 30 minutes later, a small amount of orange juice was sampled from the food outlet and diluted with sterile saline at various magnifications. 0.1 ml of the treated juice was applied to an agar medium for yeast, and after 24 hours at 30 ° C, the dilution rate and the amount of application were converted from the number of colonies that appeared on the agar medium, and the yeast production was converted. Residual bacteria Number. Figure 7 shows the results.

 FIG. 7 shows the survival rate when orange juice was kept at 40 ° (:, 100 atm for 30 minutes).

 According to Fig. 7, the survival rate of the yeast added to the orange juice had already been reduced to 1Z10,000 when the orange juice was brought to the state of 40 ° C and 100 atm. As is clear from FIG. 7, the dissolution of pressurized carbon dioxide and the subsequent heating by the treatment apparatus using the hollow stirring blade of the present invention showed an excellent sterilizing effect. That is, by maintaining the state at 40 ° C and 100 atm for 5 minutes, the number of surviving bacteria could be reduced to 10 or less Zm1.

Comparative Example 1

 In this comparative example, the death rate of the yeast (Saccharomvces cerevisiae) was determined using a dead-end type reaction tank (see FIG. 8).

 The dead-end type reaction tank is equipped with a microfilter (pore diameter: 10 m) at the bottom of the treatment tank (volume 250 ml) to make pressurized carbon dioxide finer and generate it in orange juice. I have.

 A processing tank that circulates 40 orange juice through a jacket at 40 ° C is filled with 40% orange juice leaving about 25% of the upper space, and pressurized carbon dioxide is supplied from the bottom of the processing tank. When the internal pressure reached 100 atm, the supply of pressurized carbon dioxide was stopped. At this time, the concentration of dissolved carbon dioxide was 0.71M. Thereafter, this state was maintained, and when 0, 5, 10, 20, and 30 minutes had elapsed, a small amount of orange juice was sampled from the food outlet at the bottom of the treatment tank and used for counting the number of surviving bacteria. The method for measuring the survival bacteria was the same as in Example 2. Figure 9 shows the results.

From FIG. 9, it was found that in the Dead-end type reaction tank, the dissolution of carbon dioxide was insufficient, and the obtained bactericidal effect was extremely small, so that it could not be practically used as a sterilizing technique for liquid foods. In addition, the adsorption of yeast on the treatment tank wall However, due to the large number of surviving bacteria in the juice, no tailing reduction was observed in the death curve.

Comparative Example 2

 In this comparative example, the mortality of yeast (Saccharomyces cerevisiae) was determined using a vented reaction tank (see FIG. 10).

 The vented reaction tank has a structure in which a pressure regulating valve is provided on the top of the Dead-end type reaction tank in Comparative Example 1 so that the ventilation of pressurized carbon dioxide is maintained even after a predetermined pressure is reached. This is a method of discharging carbon dioxide through a pressure regulating valve.

 Orange juice heated to 40 ° C in advance and warm water at 40 ° C are circulated through a jacket in a treatment tank in which a pressure regulating valve is arranged at the top of the Dend-end type reaction tank of Comparative Example 1. Filled into a treatment tank, and pressurized carbon dioxide was supplied at a rate of 6 liters per minute (standard condition) from the mixer port filter at the bottom of the treatment tank. Five minutes after the start of carbon dioxide supply, dissolved carbon dioxide was removed. The concentration reached 1.2 M. Thereafter, at 0, 5, 10, 20, and 30 minutes, a small amount of orange juice was sampled from the liquid food outlet at the bottom of the treatment tank and used for counting the number of surviving bacteria. The method for measuring the survival bacteria was the same as in Example 2. The results are shown in FIG.

 From Fig. 11, it is considered that carbon dioxide was sufficiently dissolved from the initial rapid death behavior. However, after 5 minutes, the slope of the survival curve became smaller, and the sterilization rate was found to decrease (tailing phenomenon). This is considered to be a phenomenon that occurred because the yeast adsorbed on the inner wall of the treatment tank did not come in contact with a sufficient concentration of carbon dioxide.

From Comparative Example 1 and Comparative Example 2, it was found that a dissolved carbon dioxide concentration of 0.71 M was insufficient to obtain a sufficient bactericidal effect at 40 ° C. Furthermore, in order to reduce the number of surviving bacteria to 1Z1, 0000, 0000, a slight stirring effect due to the rise of microbubbles of pressurized carbon dioxide in the sample solution is not enough. Yes, strong It has been found that a regular stirring operation is essential.

Comparative Example 3

 In this comparative example, yeast (Saccharomvces) was used by using a vented reaction tank (see Fig. 12) in which a stirring blade with a mechanical seal was inserted into the vented reaction tank (see Fig. 10) used in Comparative Example 2. cerevisiae) was measured.

 Orange juice preheated to 40 ° C is filled into a treatment tank with warm water at 40 ° C circulated through a jacket, and pressurized carbon dioxide is supplied at 6 liters / minute from the microfil at the bottom of the treatment tank. The process of sufficiently stirring the juice with the stirring blade while supplying at the ratio of (standard condition) was continued until the sampling of the orange juice was completed. After 5 minutes from the start of the supply of pressurized carbon dioxide, the concentration of dissolved carbon dioxide reached 1.2 M, and this point was regarded as the starting point of the processing time, and 0, 5, 10, 20, 23 After a lapse of 0 minutes, sampling was performed. Figure 13 shows the results.

 From FIG. 13, a bactericidal effect equivalent to that of Example 2 was obtained. However, in this comparative example, although a sufficient bactericidal effect could be obtained, the aroma component in the orange juice was significantly reduced due to the ventilation system.

Example 3

 In this embodiment, a processing apparatus provided with the baffle plate fixed to the inner wall of the processing tank, the turbine-type stirring blade rotating in the processing tank, and the propeller-type stirring blade shown in Embodiment 4 of the present invention (FIG. The killing rate of yeast (Saccharomvces cerevisiae) was measured using the method described in (14).

Orange juice preliminarily heated to 40 ° C was filled in a treatment tank in which warm water at 40 ° C was circulated through a jacket while leaving 10% of its volume. Next, pressurized carbon dioxide (100 atm) was introduced into the void, and the pressurized carbon dioxide was dissolved in the juice by rotating the stirring blade at 600 rpm. After 5 minutes, the concentration of dissolved carbon dioxide reached 1.2 M. After 0, 5, 10, and 20 minutes, a small amount of orange juice was sampled from the liquid food outlet at the bottom of the treatment tank and used for counting the number of surviving bacteria. The method for measuring the survival bacteria was the same as in Example 2. Figure 15 shows the results.

 From FIG. 15, it can be seen that a result equivalent to that of Example 2 was obtained. In addition, since the reaction tank used in this example was a non-vented reaction tank, it was possible to suppress the reduction of the flavor components in the orange juice.

Example 4

 In this example, the content of aroma components in the processed fruit juice was examined using the processing apparatus according to the third embodiment of the present invention.

 After dissolving carbon dioxide in the orange juice in the same manner as in Example 2, the hollow shaft was kept rotating, and hot water of about 55 ° C was circulated through the jacket of the treatment tank to remove orange juice. After heating the orange juice to 40 ° C and keeping it at 100 atm for 15 minutes to complete sterilization, the pressure in the treatment tank was raised to 1 by the pressure regulating valve while continuing to stir. Reduced to 0 atm. In addition, inert gas was supplied from the pressurized cylinder at a flow rate of 1 liter per minute (standard condition) for 2 minutes while continuing stirring to remove dissolved carbon dioxide to a level where its taste could not be perceived by humans. Finally, after reducing the pressure of the inert gas to atmospheric pressure, orange juice for aroma component analysis was collected.

 The method of quantifying the odor component is as follows.

Take 10 OmL of the treated juice into a separatory funnel, extract it three times with 7 OmL of getyl ether, combine the ether extracts, and add an internal standard (cyclohexanol) for quantification. A certain amount was added, and ether was vaporized by a predetermined method, and this was concentrated to 0.1 mL. 1 L of this ether concentrate was supplied to a gas chromatograph direct mass spectrometer to identify and quantify each flavor component. The results are shown in Table 1. According to Table 1, limonene (terpene hydrocarbon), which is the most abundant in orange juice and contributes to the fragrance of citrus juice, is over 90%, and linalool and Nero contribute significantly to the fragrance of fresh citrus fruit. One liter (all terpene alcohols) was found to be more than 95% in the juice, and the same refreshing aroma of neral and geranial (terpene aldehyde) was more than 90%. In each case, the untreated fruit juice is 100%.

Example 5

 In this example, the fragrance component content in the processed juice was examined in the same manner as in Example 4, using the processing apparatus of Embodiment 4 (see FIG. 14).

 Orange juice preliminarily heated to 40 ° C was filled in a treatment tank in which warm water at 40 ° C was circulated through a jacket while leaving 10% of its volume. Subsequently, pressurized carbon dioxide (100 atm) was introduced into the gap, and the step of rotating the stirring blade at 600 rpm per minute was continued for 15 minutes as in Example 3, and sterilization was completed. , The pressure in the processing tank was reduced to 10 atm by the pressure regulating valve. Dissolved carbon dioxide is removed to a level that humans cannot perceive by adding an inert gas from the pressurized cylinder at a flow rate of 1 liter per minute (standard condition) for 2 minutes while continuing stirring. . Finally, the pressure of the inert gas was reduced to atmospheric pressure, and orange juice for aroma component analysis was collected. Thereafter, the orange juice was subjected to aroma component analysis in the same manner as in Example 3. The results are shown in Table 1. From Table 1, it was found that limonene, linalool, nerol, neral and geranial were retained in the juice at almost the same level as in Example 4.

Comparative Example 4

 In this comparative example, the aroma component content in the treated juice was examined in the same manner as in Example 3 using the aeration type reaction tank (see FIG. 12) used in Comparative Example 3.

Orange juice preheated to 40 ° C is filled into a treatment tank with warm water at 40 ° C circulated through a jacket, and pressurized dioxide is passed through a micro-mouth filter at the bottom of the treatment tank. While supplying carbon (100 atm) at a rate of 6 liters per minute (standard state), the process of sufficiently stirring the juice with the stirring blade was continued for 15 minutes as in Example 3, and the sterilization was completed. While the stirring was continued, the pressure in the processing tank was reduced to 10 atm by the pressure regulating valve. The dissolved carbon dioxide was removed to a level where humans could not sense the taste by supplying inert gas from the pressurized cylinder at a flow rate of 1 liter per minute (standard condition) for 2 minutes while continuing stirring. Finally, the pressure of the inert gas was reduced to atmospheric pressure, and then orange juice for flavor analysis was collected. Thereafter, the orange juice was subjected to aroma component analysis in the same manner as in Example 3. The results are shown in Table 1.

 Table 1 shows that limonene was reduced to about 40% of untreated juice. Linal and nerol were relatively well retained, while neral and geranial decreased to about 60%. This is mainly due to the extraction of aroma components by aeration of pressurized carbon dioxide and discharge to the outside of the treatment tank.

 Therefore, as a means for dissolving the pressurized carbon dioxide, a circulation system that does not discharge the pressurized carbon dioxide out of the treatment tank is preferable.

table 1

Industrial applicability

According to the present invention, the liquid food can be added to the liquid food without losing the aroma components. Pressurized carbon dioxide is dissolved to a high concentration, the temperature of the liquid food is raised according to the purpose, the liquid food in which the carbon dioxide is dissolved is maintained according to the purpose, and sterilization is performed efficiently. It is possible to efficiently remove carbon dioxide dissolved in water and suppress concentration polarization of volatile components such as aroma components. In addition, space can be saved by downsizing the device, and cost can be reduced.

 Since a circulating treatment tank is used, carbon dioxide can be dissolved more efficiently than a non-circulation treatment tank (Dead-end method) or a vented treatment tank, and the amount of carbon dioxide used And the loss of flavor components can be minimized.

 By stirring the liquid food in the processing tank, the concentration of dissolved carbon dioxide in the processing tank and the temperature of the liquid food can be kept constant. Furthermore, adsorption of microorganisms on the wall surface in the treatment tank can be suppressed, and high sterilization efficiency can be obtained.

 Dissolution of carbon dioxideMaintenance of carbon dioxide concentration and liquid food temperatureRemoval of dissolved carbon dioxide can be carried out in the same treatment tank at different times, so a high-pressure pump for liquid food This eliminates the need for installation and saves space. In addition, a wide range of conditions can be set, a long residence time can be set, the amount of carbon dioxide used is small, and carbon dioxide can be easily recycled. Furthermore, since only pressure control in the processing tank is required and flow rate control is not required, system control is easy, safety is excellent, and an energy saving system can be realized.

 After efficiently sterilizing liquid foods using pressurized carbon dioxide, humans can detect carbon dioxide contained at a concentration that can be easily detected by humans before filling liquid foods into containers. It can be removed to a level that is not performed.

Claims

The scope of the claims 1. Introduce pressurized carbon dioxide into a processing tank filled with liquid food, dissolve carbon dioxide in the liquid food by stirring and circulating the pressurized carbon dioxide in the liquid food in the processing tank, and A first step of making the concentration of dissolved carbon dioxide in the liquid food uniform, deactivating enzymes contained in the liquid food while keeping the concentration of dissolved carbon dioxide in the liquid food uniform, and / or eliminating microorganisms. In the second step to maintain the conditions for killing, and after exhausting a part of the pressurized carbon dioxide, pass inert gas into the liquid food and agitate the inert gas into the liquid food in the treatment tank. A method for treating a liquid food, comprising a third step of removing dissolved carbon dioxide by circulating.  2. Provide a step of heating the pressurized carbon dioxide-dissolved liquid food after the first step, and / or a step of cooling the pressurized carbon dioxide-dissolved liquid food after the second step. 2. The method for treating a liquid food according to claim 1, comprising:  3. A processing apparatus for a liquid food having a gas inlet and a gas outlet, a liquid food inlet and a liquid food outlet in a processing tank, and a built-in rotatable hollow shaft, (1) The contact portion between the hollow shaft and the processing tank is formed in an airtight manner. (2) The hollow shaft is provided with a carbon dioxide or inert gas suction port at an end thereof. A gas dispersing device having a plurality of small holes for dispersing carbon dioxide or an inert gas formed in communication with the hollow shaft is provided at the position, and further, the hollow shaft communicates with the hollow shaft or An apparatus for treating a liquid food, comprising a plurality of stirring blades that are not communicated.  4. The liquid food processing apparatus according to claim 3, wherein the processing tank is provided with means for heating or cooling the liquid food. 5. Gas inlet and gas outlet, liquid food inlet and liquid food A liquid food processing apparatus having a product discharge port and at least one baffle plate fixed to an inner wall surface of the processing tank, and having a built-in rotatable stirring shaft, wherein (1) the stirring shaft, the processing tank, (2) The stirring shaft is provided with one turbine-type stirring blade provided near the liquid surface of the liquid food and at least one propeller-type stirring blade provided below the turbine-type stirring blade. An apparatus for treating liquid food, comprising:  6. The liquid food processing apparatus according to claim 5, wherein the processing tank is provided with means for heating or cooling the liquid food.