Method for manufacturing fluid food products and apparatus for manufacturing fluid food products

Abstract

To provide a method for producing liquid food and a liquid food production apparatus that can reduce the scale of the apparatus by suppressing the voltage for Joule heating to a low level, while still achieving a sufficient heat sterilization effect on the liquid food. [Solution] The method for producing a fluid food comprises a high-concentration food preparation step for preparing a high-concentration food, a Joule heating step for heat sterilizing the high-concentration food prepared in the high-concentration food preparation step by Joule heating, a low-concentration liquid preparation step for preparing a low-concentration liquid, and a mixing step for mixing the high-concentration food heat sterilized in the Joule heating step with the low-concentration liquid prepared in the low-concentration liquid preparation step.

Description

Technical Field

[0001] The present invention relates to a method for producing a fluid food and an apparatus for producing a fluid food, in which a high-concentration food and a low-concentration liquid are separately sterilized and then mixed.

Background Art

[0002] Conventionally, in the production of foods in sealed containers such as retort foods and chilled foods, sterilization is performed by filling ingredients into a container, sealing and packaging them, and then heating and / or pressurizing. And, as one specific method of cooking and sterilizing a fluid food having fluidity, while continuously flowing and transferring the food in a pipe, the food itself is heated by directly energizing the food using the electrical resistance of the food, that is, a method by so-called Joule heating is known (for example, see Patent Document 1). In the external heating method by heat conduction, in order to obtain a sufficient heat sterilization effect, excessive heating is often performed compared to general cooking heating, and as a result, there is a risk that the original flavor and color tone of the food may be impaired. However, in the method by Joule heating, the food is uniformly heated, so there is an advantage that the heating time is relatively short and heating deterioration such as the flavor and color tone of the food is unlikely to occur. In addition, since the food can be heated while being continuously conveyed in a pipe, sterilization can be performed more efficiently compared to the batch type in which the food is repeatedly heated in a stationary state in a container.

[0003] However, when performing sterilization treatment by Joule heating on a food having a low conductivity, in order to heat to a desired temperature for the purpose of obtaining a desired sterilized state, a high voltage is necessarily required, and there is a problem that the scale of the apparatus itself becomes large. Also, when performing sterilization treatment by Joule heating on a food having a high conductivity originally, there may be a case where the processing capacity of the apparatus for the food is excessive, and there is also a problem that the production cost becomes relatively high.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-198541 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention solves the above-mentioned problems and aims to provide a method for producing fluid foods and a apparatus for producing fluid foods that can achieve a sufficient heat sterilization effect on fluid foods while reducing the scale of the apparatus by suppressing the voltage for Joule heating. [Means for solving the problem]

[0006] The present invention provides a method for producing a fluid food, comprising a high-concentration food preparation step for preparing a high-concentration food, A Joule heating step is performed to heat-sterilize the high-concentration food prepared in the high-concentration food preparation step by Joule heating. A low-concentration liquid preparation step for preparing a low-concentration liquid, A mixing step in which the high-concentration food that has been heat-sterilized in the Joule heating step is mixed with the low-concentration liquid prepared in the low-concentration liquid preparation step. It is characterized by having the following features.

[0007] The present invention provides a method for producing fluid food products, which may include a low-concentration liquid sterilization step in which the low-concentration liquid prepared in the low-concentration liquid preparation step is sterilized before the mixing step.

[0008] In the method for producing the fluid food of the present invention, it is preferable that the conductivity of the high-concentration food is 700 to 60,000 μS / cm. It is also preferable that the viscosity of the high-concentration food is 1 to 5,000 mPa·s.

[0009] In the method for producing a fluid food according to the present invention, it is preferable that the high-concentration food is a mixture of a fluid and a solid, and that the ratio of the conductivity of the fluid to the conductivity of the solid is 1:0.7 to 1:1.3.

[0010] In the method for producing fluid food according to the present invention, the method may include a step of cooling the heat-sterilized high-concentration food between the Joule heating step and the mixing step. Furthermore, the configuration may include a filling and sealing step after the mixing step, in which the mixture is aseptically filled and sealed into a sealed container.

[0011] The present invention provides a liquid food manufacturing apparatus comprising a Joule heating apparatus equipped with a heating pipe that continuously flows a high-concentration food while Joule heating it, A high-concentration food distribution pipe for distributing the high-concentration food discharged from the Joule heating device, A flow pipe for low-concentration liquids that circulates sterilized low-concentration liquids, A confluence pipe to which the aforementioned high-concentration food supply pipe and the aforementioned low-concentration liquid supply pipe are connected, The system is characterized by having a mixing tank that contains the high-concentration food and low-concentration liquid, which have been mixed in the aforementioned confluence pipe, while maintaining a sterilized state.

[0012] The fluid food manufacturing apparatus of the present invention can be configured to include a sterilization device for sterilizing the low-concentration liquid before it flows through the low-concentration liquid flow pipe.

[0013] The present invention provides a method for producing a fluid food, comprising a high-concentration food preparation step for preparing a high-concentration food with an electrical conductivity of 700 to 60,000 μS / cm, A Joule heating step is performed to heat-sterilize the high-concentration food prepared in the high-concentration food preparation step by Joule heating. The method is characterized by having a filling and sealing step in which, after the high-concentration food preparation step, food materials other than the high-concentration food are aseptically filled and sealed into a sealed container without mixing.

[0014] The present invention provides a liquid food manufacturing apparatus comprising a Joule heating apparatus equipped with a heating pipe that continuously flows a high-concentration food while Joule heating it, A high-concentration food distribution pipe for distributing the high-concentration food discharged from the Joule heating device, The invention is characterized by having a filling and sealing device that aseptically fills and seals only the high-concentration food that flows through the aforementioned high-concentration food distribution pipe into a sealed container. [Effects of the Invention]

[0015] The present invention provides a method for producing fluid food products and a fluid food product manufacturing apparatus. By having a Joule heating step in which a high-concentration food product is heat-sterilized by Joule heating and a mixing step in which a pre-sterilized low-concentration liquid is mixed, even when the overall conductivity of the fluid food product is low, the fluid food product can be considered as a mixture of a high-concentration food product with increased conductivity and a low-concentration liquid that functions as a diluent for the high-concentration food product. By performing sterilization treatment on at least the high-concentration food product by Joule heating, the high-concentration food product can be sufficiently heat-sterilized even at a low voltage. Therefore, by diluting the high-concentration food product with a sterilized low-concentration liquid after sterilization treatment by Joule heating, the size of the apparatus can be kept small while obtaining a sufficient heat-sterilization effect on the fluid food product. As a result, fluid food products can be manufactured with high production efficiency while ensuring food safety. Furthermore, when the overall conductivity of the fluid food product is high, the voltage required for Joule heating can be further reduced by separating it into a high-concentration food product and a low-concentration liquid, thereby reducing the processing capacity and thus the size of the apparatus, and thus achieving extremely high production efficiency. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram illustrating a liquid food manufacturing apparatus according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view illustrating a Joule heating device in a fluid food manufacturing apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0017] Hereinafter, the present invention will be described in detail. <Method for Producing Fluid Food> The method for producing a fluid food according to the present invention includes a high-concentration food preparation step for preparing a high-concentration food, a Joule heating step for heat-treating the high-concentration food prepared in the high-concentration food preparation step by Joule heating, a low-concentration liquid preparation step for preparing a low-concentration liquid, and a mixing step for mixing the high-concentration food heat-treated in the Joule heating step and the low-concentration liquid prepared in the low-concentration liquid preparation step. Further, it is preferable to have a low-concentration liquid sterilization step for sterilizing the low-concentration liquid prepared in the low-concentration liquid preparation step before the mixing step, or a cooling step for cooling the high-concentration food heat-treated in the Joule heating step before the mixing step. Further, after the mixing step, it can be configured to have a filling and sealing step of aseptically filling and sealing into a sealed container.

[0018] 〔Fluid Food〕 A fluid food is a mixture of a high-concentration food and a low-concentration liquid and has fluidity. In the present invention, a fluid food refers to a food (beverage and food) having fluidity. Not only foods consisting only of fluid substances, but also mixtures of solid substances and fluid substances are included as long as they can be fluid-transported in the flow path R3 (see FIG. 1) described later. A solid substance is a solid food having a certain shape and volume, and a fluid substance is a food having fluidity and not containing solid substances. Specific examples of fluid foods include mixed foods of solid and fluid substances such as curry, stew, beef stroganoff, borscht, minestrone, clam chowder, corn puree, pasta sauce, oden, miso soup with ingredients, pork soup, congee, rice gruel, soup stock powder, etc.; foods consisting only of fluid substances such as tomato sauce, demi-glace sauce, soup without ingredients, dashi, curry sauce, white sauce, miso soup without ingredients, amazake, condensed milk, yogurt, fresh cream, liquid seasonings, etc.; beverages such as fruit juice, juice, milk, cocoa, coffee, non-fermented tea (green tea), semi-fermented tea (oolong tea), fermented tea (black tea), carbonated beverages, alcoholic beverages, ion beverages, etc. Liquid foods may contain, as appropriate, seasonings, flavorings, sweeteners, acidulants, colorings, emulsifiers, vitamins, minerals, etc., depending on the purpose.

[0019] In the present invention, high concentration and low concentration in high-concentration foods and low-concentration liquids refer to a situation where the concentration (ion concentration) and / or conductivity of the electrolyte are higher than the required value in order to perform the desired Joule heating (electrical heating) on ​​the food or liquid at a predetermined voltage, and low concentration refers to a situation where the concentration (ion concentration) and / or conductivity of the electrolyte are lower than the required value. Examples of electrolytes include substances that, when dissolved in water, can conduct electricity through water. These include, but are not limited to, sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium phosphate, potassium phosphate, potassium carbonate, and ferrous sulfate. Furthermore, the above electrolytes can be used individually or in combination.

[0020] [Highly concentrated foods] High-concentration foods are foods that are fluid and have an electrolyte concentration and / or conductivity above the level required to perform the desired Joule heating (electrical heating) at a predetermined voltage, and include mixtures of solids and fluids as long as they can be fluidly transported within the flow path R1 (see Figure 1) described later. Solid materials contain electrolytes necessary for electrical conductivity. Specific examples of solid materials include vegetables such as potatoes, carrots, onions, radishes, celery, and cabbage; fruits such as strawberries and apples; legumes such as adzuki beans, soybeans, green peas, and kidney beans; grains such as corn, wheat, and rice; fungi such as mushrooms and shiitake; seaweed such as wakame, kelp, and mekabu; livestock meats such as beef, pork, and chicken; and seafood such as tuna, bonito, horse mackerel, mackerel, clams, mussels, and cockles, as well as processed products thereof. Fluids contain electrolytes necessary for electrical conduction and do not contain solids. Specific examples of fluids include electrolyte solutions such as saline solution, their thickeners, oils and fats, mixtures thereof, or emulsions. The ratio of solids to fluids in high-concentration foods is not particularly limited; the high-concentration food as a whole should contain enough fluids to be able to flow and be transported within the flow path R1.

[0021] The conductivity of high-concentration foods depends on the temperature of the food and its specific composition (electrolyte content). The conductivity of the high-concentration food is preferably 700 to 60,000 μS / cm at 25°C. When the conductivity of the high-concentration food is within the above range, sufficient current flows through the food, and the desired heat sterilization effect is obtained by Joule heating. On the other hand, if the conductivity of the high-concentration food is excessively low, sufficient current cannot be passed through the food, and the desired heat sterilization effect may not be obtained. Furthermore, if the conductivity of the high-concentration food is excessively high, the voltage required to obtain the desired heat sterilization effect becomes extremely small relative to the processing capacity of the device, which may result in high production costs and poor production efficiency. The conductivity of typical foods and beverages served with meals is usually between 500 and 40,000 μS / cm.

[0022] The method for measuring the conductivity of high-concentration foods involves immersing the electrodes of a conductivity meter, such as the AS710 (manufactured by AS ONE Corporation), in the fluid at 25°C. For solids, the electrodes are either directly inserted into the solid or in contact with its surface for measurement.

[0023] Furthermore, the viscosity of the high-concentration food, that is, the viscosity of the fluid contained in the high-concentration food, is preferably between 1 and 5,000 mPa·s. Having the viscosity of the high-concentration food within this range ensures good transportability within the flow path R1. On the other hand, if the viscosity of the high-concentration food is excessively high, it may hinder fluid transfer within the flow path R1.

[0024] The viscosity of high-concentration foods, i.e., the viscosity of the fluids contained in said high-concentration foods, was measured using a B-type viscometer "LVDV-II+Pro" (manufactured by BROOKFIELD). 250 mL of the sample was filled into a beaker (Φ9 cm, 300 mL cylindrical) at 25°C, and then measured using a rotor (manufactured by BROOKFIELD). The viscosity at 25°C is the viscosity at 25°C.

[0025] The viscosity (viscosity of fluids) of high-concentration foods can be adjusted, for example, by increasing or decreasing the content of oils and fats or by adding thickeners. Examples of thickeners include those commonly used as food additives, such as carrageenan, guar gum, xanthan gum, pectin, locust bean gum, curdlan, tragacanth gum, gum arabic, gellan gum, tamarind seed gum, cassia gum, tara gum, sodium alginate, agar, glucomannan, soybean polysaccharides, pullulan, psyllium, chitosan, methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, dextrin, and other thickening polysaccharides. These may be used individually or in combination of two or more.

[0026] When a high-concentration food is a mixture of fluid and solid matter, the ratio of the conductivity of the fluid to the conductivity of the solid matter is preferably 1:0.7 to 1:1.3, and more preferably 1:0.8 to 1:1.2. By having the ratio of the conductivity of the fluid to the conductivity of the solid matter within this range, the difference in electrical resistance between the fluid and solid matter in the high-concentration food is reduced. This allows for uniform and even Joule heating of the entire high-concentration food, minimizing the heating time for the entire food and reducing the likelihood of deterioration of the flavor and color of each ingredient. On the other hand, if the conductivity of the solid matter is excessively high or low compared to the conductivity of the fluid, it may not be possible to pass a sufficient current through one of the simultaneously flowing fluid and solid matter to the other. This could result in the high-concentration food not achieving the desired heat sterilization effect, or even if the desired heat sterilization effect is achieved, one side receiving too much current may be overheated, potentially leading to deterioration of its flavor and color. If the conductivity of solids in high-concentration foods is low, it can be improved by pretreatment, such as immersion treatment, in which the solids are immersed in a high-concentration electrolyte solution. Furthermore, if the conductivity of a fluid is low, it can be increased by dissolving at least one of an electrolyte and / or an electrolyte solution in the fluid.

[0027] The size of the solid particles in high-concentration foods must be such that they do not hinder fluid transfer within the flow path R1, preferably within 25 mm square, and more preferably within 20 mm square. If the size of the solid particles in high-concentration foods is excessively large, uniform Joule heating may not be possible.

[0028] [Low concentration liquid] The low-concentration liquid is a liquid that has the function of diluting high-concentration foods, and preferably does not contain solid matter. Examples of low-concentration liquids include tap water, pure water, distilled water, deionized water, mineral water, vinegar, alcohol, oils and fats, the fluids listed above, and mixtures thereof.

[0029] The proportion of low-concentration liquid in a fluid food product is the amount required to dilute a high-concentration food product having a predetermined conductivity (electrolyte concentration) so that the final product, the fluid food product, reaches the desired electrolyte concentration (e.g., salt concentration), and is determined appropriately by the product design.

[0030] <Equipment for manufacturing fluid food products> The manufacturing method for liquid food products can be carried out using the following manufacturing equipment. A fluid food manufacturing apparatus 100 according to one embodiment of the present invention includes a high-concentration food processing unit 110 for heat-sterilizing a high-concentration food W1, a low-concentration liquid processing unit 130 for sterilizing a low-concentration liquid W2, and a mixing processing unit 140 for mixing the high-concentration food W1 discharged from the high-concentration food processing unit 110 with the low-concentration liquid W2 discharged from the low-concentration liquid processing unit 130.

[0031] The high-concentration food processing unit 110 includes a high-concentration food tank 111 for containing the high-concentration food W1, a Joule heating device 120 for heat sterilizing the high-concentration food W1 by Joule heating, and a cooling pipe 115 for lowering the temperature of the high-concentration food W1 discharged from the Joule heating device 120. The high-concentration food tank 111 and the Joule heating device 120 are connected by a flow channel pipe 112, and a pressure pump 113 is inserted into the flow channel pipe 112 to continuously fluidize and transfer the high-concentration food W1 from the high-concentration food tank 111 to the Joule heating device 120 under pressure. Furthermore, the high-concentration food tank 111 may be provided with an inflow passage (not shown) for a diluent or the like to adjust the conductivity of the high-concentration food W1 inside the high-concentration food tank 111.

[0032] The Joule heating device 120 is configured by having, for example, two Joule heating modules 121 arranged in series. The Joule heating module 121 comprises a cylindrical heating pipe 122 made of an insulating material, and two annular electrodes 123A and 123B positioned at both ends of the heating pipe 122, spaced apart in the longitudinal direction, and concentric with respect to the central axis of the heating pipe 122. The annular electrodes 123A and 123B can be formed from electrode materials such as titanium or platinum. The inside of the heating pipe 122 is part of the flow path R1 through which the high-concentration food W1 is fluidly transferred, and the region between the annular electrodes 123A and 123B exposed in the flow path R1 is designated as the heating region RH through which the high-concentration food W1 is Joule heated. Adjacent Joule heating modules 121, 121 are connected to each other by short insulating tubes 125. In Figure 2, reference numeral 127 denotes a water channel for circulating cooling water.

[0033] The annular electrodes 123A and 123B constitute an electrode pair and are electrically connected to a power supply unit (not shown). When a voltage is applied between the upstream annular electrode 123A and the downstream annular electrode 123B of the flow path R1, the high-concentration food W1 flowing through the heating region RH of the flow path R1 is Joule heated by the current flowing between the annular electrodes 123A and 123B and continuously heated to a predetermined heat sterilization temperature.

[0034] Furthermore, the Joule heating apparatus is not particularly limited to those described above, and various conventionally known apparatuses can be used as appropriate. Furthermore, in the example shown in Figure 1, two Joule heating modules 121 are arranged in series, and the high-concentration food W1 is configured to pass sequentially through the heating region RH of each module 121. However, the number of Joule heating modules 121 is not limited to this, and they should be designed to be long enough to achieve the desired heat sterilization effect while flowing through the heating region RH of the flow path R1.

[0035] The cooling tube 115 cools the high-concentration food W1 discharged from the Joule heating device 120 while continuously flowing and transferring it, maintaining its sterilized state. It can be a cooling method of any known type, such as air cooling, water cooling, or air cooling. In this invention, the term "sterilized state" means a state in which the number of bacteria in the object has been reduced to a level that is acceptable according to the purpose.

[0036] The low-concentration liquid processing unit 130 includes a low-concentration liquid tank (not shown) for containing the low-concentration liquid W2 and a sterilization device 135 for sterilizing the low-concentration liquid W2. It should be noted that providing a low-concentration liquid tank is not mandatory; the low-concentration liquid W2 may be supplied directly to the flow path R2 related to the low-concentration liquid W2. The low-concentration liquid processing unit 130 may have a cooling member that lowers the temperature of the low-concentration liquid W2 discharged from the low-concentration liquid tank, or the low-concentration liquid W2 discharged from the sterilization device 135, to a desired refrigeration temperature. The low-concentration liquid tank and the sterilization device 135 are connected by a flow channel pipe 132, and a pressurizing pump 133 is inserted into the flow channel pipe 132 to continuously flow and transfer the low-concentration liquid W2 from the low-concentration liquid tank to the sterilization device 135 under pressure.

[0037] The sterilization device 135 can be any device capable of sterilizing a low-concentration liquid W2 to a desired sterilization state, and various known sterilization methods such as UV irradiation or direct heating can be used.

[0038] The mixing section 140 includes a mixing tank 141, a confluence pipe 142 connected to the inlet of the mixing tank 141, a high-concentration food distribution pipe 145 that connects to the confluence pipe 142 while continuously flowing and transferring the high-concentration food W1 discharged from the cooling pipe 115 of the high-concentration food section 110 while maintaining its sterilization state, and a low-concentration liquid distribution pipe 146 that connects to the confluence pipe 142 while continuously flowing and transferring the low-concentration liquid W2 discharged from the sterilization device 135 of the low-concentration liquid section 130 while maintaining its sterilization state. In Figure 1, reference numeral 144 denotes a drain provided in the confluence pipe 142, used when cleaning the flow paths R1 and R2, etc.

[0039] A series of flow paths R1 is formed between the high-concentration food tank 111 of the high-concentration food processing unit 110 and the confluence pipe 142 of the mixing processing unit 140, and the sterilization state of the high-concentration food W1 is maintained after it is discharged from the Joule heating device 120 of the high-concentration food processing unit 110. In addition, a series of flow paths R2 is formed between the low-concentration liquid tank of the low-concentration liquid processing unit 130 and the confluence pipe 142 of the mixing processing unit 140, and the sterilization state of the low-concentration liquid W2 is maintained after it is discharged from the sterilization device 135 of the low-concentration liquid processing unit 130. Furthermore, the mixing tank 141 contains the high-concentration food W1 and low-concentration liquid W2, which have been mixed in the confluence pipe 142, while maintaining a sterilized state.

[0040] In the above-described liquid food manufacturing apparatus, liquid food is manufactured as follows. In the high-concentration food processing unit 110, a high-concentration food preparation process is first carried out to prepare the high-concentration food W1, which is then stored in the high-concentration food tank 111. In the present invention, preparing the high-concentration food W1 includes not only mixing solids and fluids, and adjusting the electrolyte concentration of the solids, fluids, or the entire high-concentration food W1, but also simply preparing (mixing, manufacturing, and supplying) the high-concentration food W1. The high-concentration food W1 stored in the high-concentration food tank 111 is preferably maintained at a temperature of, for example, 25 to 80°C, from the viewpoint of adjusting viscosity related to transportability. Next, the high-concentration food W1 contained in the high-concentration food tank 111 is supplied to the flow path R1 by the pressurizing pump 113 at a rate of, for example, 400 kg / h. Specifically, it is fluidized and transferred from the high-concentration food tank 111 to the Joule heating device 120 via the flow path pipe 112. In the Joule heating device 120, a Joule heating process is performed. Specifically, a voltage is applied between the annular electrodes 123A and 123B in each Joule heating module 121, and the high-concentration food W1 passing through the heating region RH in the heating pipe 122 of each Joule heating module 121 is Joule heated by the current flowing between the annular electrodes 123A and 123B, and the high-concentration food W1 is continuously heated to the heat sterilization temperature, thereby performing a predetermined heat sterilization process. Regarding the voltage applied in the Joule heating device 120, for example, if the conductivity of the target food is 1.5 times higher than that of the low-concentration food, the voltage required for heat sterilization by Joule heating of the low-concentration food can be reduced from 130-140V to 90-100V for the high-concentration food. Therefore, a power supply unit with a predetermined voltage set between 90 and 100V can be used. Examples of heat sterilization processes include retort sterilization, which allows for distribution at room temperature, and heat treatment, which allows for chilled distribution. However, these are not limited to these, and various known sterilization conditions can be adopted depending on the design of the final product. Retort sterilization refers to processing to achieve an F0 value of 3.1 minutes or more, which is equivalent to at least 120°C for 4 minutes. Heat treatment for chilled distribution refers to, for example, heat treatment equivalent to 90°C for 10 minutes or more, which is commonly used. Furthermore, heat sterilization may also be combined with the cooking process. The high-concentration food W1, which has undergone the Joule heating process, is continuously supplied to the cooling pipe 115. The high-concentration food W1 is cooled while being fluidized and transferred through the flow path R1 in the cooling pipe 115 while maintaining a sterilized state. In the cooling process, it is preferable that the high-concentration food W1 is cooled to a cooling temperature of approximately 40 to 80°C. The high-concentration food W1 that has undergone the cooling process is supplied from the cooling pipe 115 to the high-concentration food distribution pipe 145.

[0041] Meanwhile, in the low-concentration liquid processing unit 130, a low-concentration liquid preparation process is performed to prepare the low-concentration liquid W2, which is then stored in the low-concentration liquid tank. In this invention, preparing the low-concentration liquid W2 includes adjusting the temperature of the low-concentration liquid W2 or simply supplying the low-concentration liquid W2. Furthermore, the low-concentration liquid W2 prepared in the low-concentration liquid preparation process may be sterilized beforehand, in which case a sterilization process for the low-concentration liquid W2 may not be required. The low-concentration liquid W2 contained in the low-concentration liquid tank is supplied to the flow path R2 at a rate of 200-300 kg / h by the pressurizing pump 133. Specifically, the low-concentration liquid W2 is fluidized and transferred from the low-concentration liquid tank to the sterilization device 135 via the flow path pipe 132, where an appropriate sterilization process, i.e., a low-concentration liquid sterilization process, is performed. The sterilization process should be one that provides a sterilization effect similar to that of the high-concentration food W1 in the Joule heating process. That is, for example, if it is a retort sterilization process that enables distribution at room temperature, the process should be performed to achieve an F0 value of 3.1 minutes or more, which is equivalent to at least 120°C for 4 minutes or more, and if it is a heat treatment that enables chilled distribution, a heat treatment equivalent to 90°C for 10 minutes or more, which is commonly used, should be performed. Furthermore, the low-concentration liquid W2 discharged from the sterilization device 135 is supplied to the low-concentration liquid flow pipe 146 and continuously fluidized while being appropriately cooled to a refrigeration temperature of, for example, 0 to 10°C. The temperature of the low-concentration liquid W2 after cooling will vary depending on the cooling temperature of the high-concentration food W1, but it is preferable that the temperature of the fluid food W contained in the mixing tank 141 be, for example, 30 to 50°C. If the temperature of the fluid food W contained in the mixing tank 141 is excessively high, the cooking process of the fluid food W may proceed, thermal degradation may occur, and in the filling and sealing process described later, if the fluid food W contains a large amount of oil, the resin material or resin layer of the sealing container may melt, which is undesirable.

[0042] Then, a mixing process is carried out in the mixing section 140. Specifically, the high-concentration food W1 is supplied to the confluence pipe 142 via the high-concentration food distribution pipe 145 while being kept at a cooling temperature during the cooling process, and the low-concentration liquid W2 is supplied to the confluence pipe 142 via the low-concentration liquid distribution pipe 146 while being kept at an appropriate refrigeration temperature. These are mixed in the confluence pipe 142, that is, the high-concentration food W1 is diluted by the low-concentration liquid W2 to become a fluid food W, which is then stored in the mixing tank 141.

[0043] The liquid food W contained in the mixing tank 141 is subjected to the filling and sealing process without being exposed to the external environment while maintaining a sterilized state, and is aseptically filled and sealed into a sealed container. Specifically, the fluid food W is fluidized and transferred from the mixing tank 141 to the filling tank 151 through the flow path R3 in the filling supply pipe 152, while being depressurized by a vacuum pump 153 inserted in the filling supply pipe 152 connecting the mixing tank 141 and the filling tank 151. The fluid food W contained in the filling tank 151 is then individually packaged in sealed containers in a sterile environment while maintaining its sterilization state, by an aseptic packaging device 155, such as an aseptic pillow packaging machine, which can individually fill and seal the product in a sterile state, thereby obtaining product A. When filling a liquid food product W into a sealed container, the container may be filled with gas as needed. The gas to be filled is preferably a highly sterilized gas, and examples of gases include air, inert gases such as nitrogen gas and carbon dioxide, water vapor, or mixtures thereof.

[0044] Examples of airtight containers include, but are not limited to, bag-shaped or rigid container-shaped containers that have airtightness and practical strength for room temperature or chilled distribution. It is preferable to use containers that can be heated in a microwave oven or in a water bath. Examples of rigid container-shaped containers include resin cup containers or tray containers with openings sealed by heat-sealing, for example, a plastic film; canned food containers with metal cans sealed with rigid metal lids; and bottled food containers with resin or glass bottles sealed with resin or metal caps. Examples of bag-shaped containers include pouches with resin bags that can be sealed by heat-sealing. Furthermore, bag-shaped containers may be provided with additional functionality, such as heat resistance for high-temperature heat sterilization, barrier properties to block oxygen gas and light, easy opening, self-standing ability, and microwave heating compatibility.

[0045] The liquid food products obtained in the sealed containers as described above are specifically so-called retort foods and chilled foods, and no further heat sterilization or other treatments are required after the filling and sealing process.

[0046] Although a method for producing a fluid food and an apparatus for producing a fluid food according to the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. For example, if a liquid food is a food with a high electrolyte concentration that is intended to be diluted with water or other liquids by the user before use, then a high-concentration food can be used as the final liquid food product. [Examples]

[0047] The following describes examples of the present invention.

[0048] <Example 1> A liquid food manufacturing apparatus, as shown in Figure 1, was fabricated. For the Joule heating module of the Joule heating apparatus, a "Joule Heating Test Apparatus" (manufactured by Frontier Engineering Co., Ltd.) was used. [Sample conditions] ·Highly concentrated foods Potatoes were cut into a predetermined size (20 mm cubes) and pre-treated by boiling them in a 0.5% NaCl solution as an electrolyte solution at 85°C for 10 minutes. After cooling the pre-treated solids to 65°C, they were mixed with a high-concentration curry sauce as a liquid in a fixed ratio (solids:liquid = 1:2) to create a high-concentration food product. The conductivity of the high-concentration curry sauce is 27,400 μS / cm, and its viscosity is 230 mPa·s. The electrical conductivity of potatoes after mixing with a high-concentration curry sauce is 25,600 μS / cm. ·Low concentration liquid As a low-concentration liquid, we prepared mineral water at 20°C.

[0049] [Manufacturing conditions] • Temperature of high-concentration food in high-concentration food tank: 60°C • Supply volume of high-concentration food: 80 L / h (pressurized at a pressure of 0.35 MPa) • Applied voltage to Joule heating module: 200~350V Joule heating temperature: 135.5℃ • Cooling temperature for high-concentration foods: 60°C • Low-concentration liquid supply rate: 40 L / h (pressurized at 0.35 MPa) • Refrigeration temperature for low-concentration liquids: 5℃ • Temperature of the food fluid in the mixing tank: 40°C Furthermore, the conductivity of the mixed liquid food (curry) in the mixing tank is low, around 14,500 μS / cm. Therefore, in order to heat this liquid food (curry) in the same manner as in Example 1, a higher-grade device capable of applying a voltage of around 500V would be required. [Industrial applicability]

[0050] The method for producing fluid foods of the present invention can be applied to the production of retort foods and chilled foods consisting of fluid foods. [Explanation of Symbols]

[0051] 100 Fluid Food Manufacturing Equipment 110 High-Concentration Food Processing Unit 111 High-concentration food tanks 112 Flow Tube 113 Pressure pump 115 Cooling pipe 120 Joule heating device 121 Joule heating module 122 Heating pipe 123A, 123B annular electrodes 125 Insulating tube 127 Waterway 130 Low-concentration liquid treatment section 132 Flow Tube 133 Pressure pump 135 Sterilizer 140 Mixing section 141 Mixing tank 142 Confluence pipe 144 Drain 145 Distribution pipe for high concentration food 146 Flow pipe for low concentration liquid 151 Filling Tank 152 Filling supply pipe 153 Pressure Reducing Pump 155 Aseptic packaging equipment W fluid food W1 Highly concentrated food W2 Low concentration liquid

Claims

1. A high-concentration food preparation process for preparing high-concentration foods, A Joule heating step is performed to heat-sterilize the high-concentration food prepared in the high-concentration food preparation step by Joule heating. A low-concentration liquid preparation step for preparing a low-concentration liquid, A mixing step in which the high-concentration food that has been heat-sterilized in the Joule heating step is mixed with the low-concentration liquid prepared in the low-concentration liquid preparation step. A method for producing a fluid food, characterized by having the following:

2. The method for producing a fluid food according to claim 1, further comprising a low-concentration liquid sterilization step in which the low-concentration liquid prepared in the low-concentration liquid preparation step is sterilized before the mixing step.

3. The method for producing a fluid food according to claim 1, characterized in that the conductivity of the high-concentration food is 700 to 60,000 μS / cm.

4. The method for producing a fluid food according to claim 1, characterized in that the viscosity of the high-concentration food is 1 to 5,000 mPa·s.

5. The aforementioned high-concentration food is a mixture of a fluid and a solid, The method for producing a fluid food according to claim 1, characterized in that the ratio of the conductivity of the fluid to the conductivity of the solid is 1:0.7 to 1:1.

3.

6. The method for producing a fluid food according to claim 1, characterized in that a cooling step for cooling a heat-sterilized high-concentration food is provided between the Joule heating step and the mixing step.

7. The method for producing a fluid food according to claim 1, further comprising a filling and sealing step of aseptically filling and sealing a sealed container after the mixing step.

8. A Joule heating device equipped with a heating pipe that continuously heats high-concentration food while passing it through, A high-concentration food distribution pipe for distributing the high-concentration food discharged from the Joule heating device, A flow pipe for low-concentration liquids that circulates sterilized low-concentration liquids, A confluence pipe to which the aforementioned high-concentration food supply pipe and the aforementioned low-concentration liquid supply pipe are connected, A liquid food manufacturing apparatus characterized by having a mixing tank that contains a high-concentration food and a low-concentration liquid in a mixed state in the aforementioned confluence pipe, while maintaining a sterilized state.

9. The apparatus for manufacturing fluid food according to claim 8, characterized in that it has a sterilization device for sterilizing the low-concentration liquid before it flows through the low-concentration liquid flow pipe.

10. A high-concentration food preparation process for preparing high-concentration foods with an electrical conductivity of 700 to 60,000 μS / cm, A Joule heating step is performed to heat-sterilize the high-concentration food prepared in the high-concentration food preparation step by Joule heating. A method for producing a fluid food, characterized by having a filling and sealing step after the high-concentration food preparation step, in which food materials other than the high-concentration food are aseptically filled and sealed into a sealed container without mixing.

11. A Joule heating device equipped with a heating pipe that continuously heats high-concentration food while passing it through, A high-concentration food distribution pipe for distributing the high-concentration food discharged from the Joule heating device, A liquid food manufacturing apparatus characterized by having a filling and sealing device that aseptically fills and seals only the high-concentration food that flows through the aforementioned high-concentration food distribution pipe into a sealed container.

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