Manufacturing method for retort pouch food products

Abstract

To provide a technique for easily producing retort pouch food products continuously produced by a filling and packaging machine by a method of high-temperature heat sterilization under atmospheric pressure. [Solution] Retort pouch food products are continuously manufactured through a cell body formation process in which retort pouch foods continuously manufactured by a filling and packaging machine are individually housed in a pair of metal cells to form cell bodies; a heat sterilization process in which the cell bodies are immersed in a heating bath filled with a heating medium having a boiling point of over 100°C to heat the contents of the retort pouch food housed in the cell bodies under atmospheric pressure; and a cooling process in which the cell bodies heat-sterilized in the heat sterilization process are immersed in a cooling bath at 50°C or less to cool the contents of the retort pouch food.

Description

[Technical field]

[0001] The present invention relates to a method for easily producing a retort pouch food product by using a filling and packaging machine that mainly uses a multilayer film (laminated plastic film) for packaging, heat-seals the film to form a pouch while filling the contents to be packaged, and then sterilizing the pouch at high temperature under atmospheric pressure to produce a retort pouch food product. [Background technology]

[0002] Retort pouch food products can be stored for long periods at room temperature because the inside of the pouch can be kept sterile. They are convenient for packaging cooked foods such as curry and stew for individual meals and are also widely used as emergency food in the event of a disaster.

[0003] Retort pouch food products are generally defined in the "Retort Pouch Food Quality Labeling Standards (Notification of the Consumer Affairs Agency)" as "containers (limited to those that are airtight and light-blocking) made of plastic film, metal foil, or multiple layers of these molded into a bag or other shape, which are filled with prepared food, sealed by thermal fusion, and sterilized by pressurized heating."

[0004] For this reason, retort pouch food products are manufactured by filling and packaging food in a pouch (container) made of a packaging multilayer film, etc. For example, as in Patent Document 1, the retort pouch food is placed in a retort oven, and high-temperature steam (or hot water) is forced into the pouch while applying pressure so that the retort pouch food does not break, and the food is kept at a high temperature (105 to 115°C is called semi-retort sterilization, 120°C is called retort sterilization, and 130°C or higher is called high-retort sterilization) for several seconds to about 30 minutes, thereby performing pressurized, heat-sterilization. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-096786 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, the heat sterilization treatment of retort pouch foods is carried out under pressure, which requires expensive and large-sized equipment. In addition, when cooling the retort pouch foods after the heat sterilization treatment, the retort pouch foods must be gradually cooled while reducing the pressure inside the retort oven so that the retort pouch foods do not break, which is time-consuming and costly.

[0007] In particular, in recent years, with the development of filling and packaging machines and multilayer films for packaging, it has become possible to continuously produce retort pouch foods at high speed. However, as described above, the efficiency of the heat sterilization treatment is low, which requires multiple retort ovens, and this has been an obstacle to improving productivity through automation.

[0008] Therefore, an object of the present invention is to provide a technique for easily producing retort pouch food products that are continuously produced by a filling and packaging machine by a method of high-temperature heat sterilization under atmospheric pressure. [Means for solving the problem]

[0009] The method for producing a retort pouch food product according to the present invention, which was developed to achieve the above object, comprises the steps of: forming a pouch by heat-sealing a strip-shaped multi-layer packaging film in a filling and packaging machine; filling and packaging the contents in the pouch to produce a retort pouch food; and then heat-sterilizing the pouch to produce a retort pouch food product. a cell body forming step of individually housing the retort pouch foods continuously produced by a filling and packaging machine in a pair of metal cells to form a cell body; a heat sterilization step of immersing the cell body in a heating bath filled with a heating medium having a boiling point of over 100°C and heating the contents of the retort pouch food contained in the cell body under atmospheric pressure; a cooling step of cooling the contents of the retort pouch food by immersing the cell body heat-sterilized in the heat sterilization step in a cooling bath at 50°C or less; The method is characterized in that a retort pouch food product is continuously produced through the steps of:

[0010] In the method for producing the retort pouch food product according to the present invention, (1) Providing a recess on at least one of the mutually opposing surfaces of the pair of cells, and accommodating the retort pouch food in the recess; (2) The retort pouch food has an outer periphery including at least a heat-sealed portion sandwiched between the outer peripheries of the pair of cells and sealed between the pair of cells; (3) The retort pouch food is such that at least the outer periphery including the inner periphery of the heat-sealed portion is sandwiched between a pair of the cells with a predetermined gap therebetween; (4) A lamination step is provided between the cell body forming step and the heat sterilization step, in which a plurality of the cell bodies are laminated to form a unit, and the cell bodies are moved in units of units. (5) The heating medium is one or more oils selected from glycerin, propylene glycol, and 1,3-butylene glycol, salt water, or a mixed liquid of the oils and water; is preferred. Effect of the Invention

[0011] According to the method for producing a retort pouch food product of the present invention, a retort pouch food is sandwiched between a pair of cells to form a cell body, and the cell body is continuously heated under atmospheric pressure using a heating medium, so that the retort pouch food products continuously produced by a filling and packaging machine can be produced by high-temperature heat sterilization under atmospheric pressure. Therefore, compared with the conventional pressurized heat sterilization method using a retort oven, the sterilization process time (the time from heating to cooling) can be shortened more easily, the productivity of retort pouch food products can be significantly improved, and the device for heat sterilization of retort pouch food can be made smaller.

[0012] According to the method for producing a retort pouch food product of the present invention, when a retort pouch food is heated at a high temperature, the contents boil and the internal pressure rises, causing it to expand, but because the retort pouch food is restrained between a pair of thin cell plates, no pressure is applied to the heat-sealed portion, and it is possible to prevent the bag from breaking due to seal retreat or a decrease in heat-seal strength. Furthermore, according to the present invention, when at least the inner edge of the heat-sealed portion located on the outer periphery of the heat-sealed portion is clamped by a pair of cells, the pressure from the contents does not directly affect the heat-sealed portion (inner edge), and bag breakage at the heat-sealed portion can be effectively suppressed. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a diagram showing one embodiment of a cell body forming step in the method for producing a retort pouch food product according to the present invention. [Diagram 2] 1A to 1D are diagrams showing one embodiment of a cell body, in which (a) is a plan view, (b) is a front view, (c) is a cross-sectional view taken along the line AA in (a), and (d) is a plan view showing the cell body in (a) with an upper cell removed. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2(a) according to another embodiment. [Figure 4] FIG. 13 is a diagram showing a state in which a plurality of cell bodies are combined into one unit, (a) being a front view and (b) being a right side view. [Diagram 5] FIG. 5 is a diagram showing the state in which the unit in FIG. 4 is suspended and moved to a heat sterilization step and a cooling step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing one embodiment of a cell body forming step in a method for producing a retort pouch food product according to the present invention. Fig. 2 is a diagram showing one embodiment of a cell body, where (a) is a plan view, (b) is a front view, (c) is a cross-sectional view taken along the line AA in (a), and (d) is a plan view showing the cell body of (a) with the upper cell removed. Fig. 3 is a diagram showing another embodiment of the cross-sectional view taken along the line AA in Fig. 2(a). Fig. 4 is a diagram showing a state in which a plurality of cell bodies are assembled into one unit, where (a) is a front view and (b) is a right side view. Fig. 5 is a diagram showing the state in which the unit of Fig. 4 is suspended and moved to the heat sterilization step and the cooling step.

[0015] The method for producing a retort pouch food product of the present invention mainly comprises a cell body forming step, a heat sterilization step, and a cooling step, and each step will be described below. In this specification, a pouch is a bag produced by a filling and packaging machine, a retort pouch food is the pouch filled and packaged with contents, and a retort pouch food product is the retort pouch food that has been heat sterilized and cooled.

[0016] (Cell body formation process) The cell body 1 is composed of a pouched food for retort pouch 11 and a pair of cells 12a, 12b (lower cell 12a, upper cell 12b) preferably in the shape of a thin plate, and is formed by conveying the pouched food for retort pouch 11 continuously produced by a filling and packaging machine 2 in sequence by a conveyor 21 and placing it on the lower cell 12a, and then covering it with the upper cell 12b from above and pressing the upper cell 12b from above, as shown in Fig. 1. The shape and thickness of the cells 12a, 12b can be changed as appropriate.

[0017] The pouched food for retort 11 is formed by a filling and packaging machine 2 such as a known vertical or horizontal filling and packaging machine. The filling and packaging machine 2 folds a strip-shaped multilayer film continuously unwound from a raw film at the center position in the width direction, vertically seals the folded-back portion and overlapping side edge portions of the multilayer film continuously in the conveying direction to form a cylindrical shape, and then fills the cylindrical multilayer film with contents while horizontally sealing in a direction perpendicular to the conveying direction, thereby continuously producing the pouched food for retort 11 having heat-sealed portions (vertical seal portion 11a, horizontal seal portion 11b) on all four sides of the outer periphery. As the multilayer film, for example, a plastic film such as PET / aluminum foil / nylon / polypropylene is preferably used, which has gas barrier properties and light-shielding properties and can withstand high temperatures of over 100°C.

[0018] The pair of cells 12a, 12b are mainly made of a molded metal such as aluminum or titanium, and aluminum in particular is one of the preferred materials because it is lightweight and has excellent thermal conductivity.

[0019] At least one of the pair of cells 12a, 12b is provided with a recess 13 in the center of the surface facing each other, as shown in Figures 2(c) and 2(d). The recess 13 is for accommodating the pouched food for retort 11 (a portion for accommodating the contents) between the pair of cells 12a, 12b inside, and is formed appropriately according to the size of the pouched food for retort 11. In this embodiment, the pair of cells 12a, 12b (lower cell 12a, upper cell 12b) are each provided with recesses 13 of the same shape (depth), but this can be modified appropriately, for example, by providing a recess 13 only in the lower cell 12a and accommodating the pouched food for retort 11 in the recess 13.

[0020] At least the inner edge of the heat-sealed portion (vertical seal portion 11a, horizontal seal portion 11b) provided on the outer periphery of the retort pouch food 11 is sandwiched between a pair of cells 12a, 12b as shown in Fig. 2(c), and the retort pouch food 11 is sealed between the pair of cells 12a, 12b. When the retort pouch food 11 is sealed (without gaps) between the pair of cells 12a, 12b, heat is uniformly transferred from the heating medium to the center and edges of the retort pouch food 11 in the heat sterilization process, and the heating time can be shortened.

[0021] At least the inner edge of the heat-sealed portion (vertical seal portion 11a, horizontal seal portion 11b) provided on the outer periphery of the pouch food for retort pouch 11 may be sandwiched between a pair of cells 12a, 12b with a predetermined gap d as shown in Fig. 3. In this case, it is preferable that the gap d is 5.0 mm or less. By setting the gap d to 5.0 mm or less, the thickness of the heat-sealed portion at the inner edge position is reduced, so that the internal pressure of the contents is less likely to be applied to the inner edge, and the pouch food for retort pouch 11 can be effectively prevented from breaking.

[0022] The cell body 1 may be integrated by fixing the lower cell 12a and the upper cell 12b with screws or the like, and transported one by one to the heat sterilization process and cooling process described below; however, it is preferable to stack multiple cell bodies 1 to form a cell unit 14 and transport each cell unit 14, as this improves productivity.

[0023] The cell unit 14 has a pair of L-shaped (inverted L-shaped) supports 32 in each storage space 31 of a cell unit device 3 as shown in Fig. 4, and the cell bodies 1 are placed one by one on the supports 32 to be stored and held (stacking process). In Fig. 4, the cell unit 14 is composed of ten cell bodies 1, but the number of layers is not particularly limited. It is preferable that the storage space 31 of the cell unit device 3 has a gap at the top when the cell bodies 1 are stored, and when the cell unit 14 is immersed in a heating bath 4 while hanging and heated as described later, the gap can absorb the thermal expansion volume of the retort pouch food 11, and the cell bodies 1 are firmly constrained within the storage space 31 by the thermal expansion of the retort pouch food 11.

[0024] The cell unit device 3 has a protrusion 34 on an upper wall surface 33, and can be held suspended by hooking a hook onto the protrusion 34, and the hook can be moved using, for example, a chain belt and a motor as shown in Fig. 5 to transport the cell body 1 as a unit of cell unit 14. Note that the cell unit 14 and cell unit device 3 may be of any type as long as they can stack a plurality of cell bodies 1 and transport them as a unit, and are not limited to those shown in the drawings.

[0025] (heat sterilization process) The heat sterilization step uses a heating bath 4. As described above, the cell unit 14 is hung by a hook attached to the protrusion 34 provided on the cell unit device 3, moved to the heating bath 4, and immersed in the heating medium 41 filled in the heating bath 4. While being immersed in the heating bath 4, the cell unit 14 is heated by the heating medium 41 during the sequential movement. Although only one heating bath 4 is provided in FIG. 5, multiple heating baths with different temperatures may be provided in series. For example, it is preferable to configure the first heating bath 4 to a 130° C. range to heat the pouched food for retort pouch 11 from room temperature, and the second heating bath 4 to a 125° C. range to maintain the heated temperature of the pouched food for retort pouch 11, as appropriate, to enable efficient heat sterilization.

[0026] The heating medium 41 is preferably salt water or an oil having a high boiling point of over 100°C, such as glycerin, propylene glycol, or 1,3-butylene glycol. Alternatively, the oil may be mixed with water, and the amount of the mixture is 20 mass% or less, preferably 15 mass% or less. The use of such a heating medium 41 is safe and can be easily removed in the cooling step described below. The heating temperature and heating time in the heating bath 4 are determined according to the specifications and contents of the retort pouch food product, and in the case of retort sterilization, the contents are heated so that the central temperature is maintained at 120°C for 4 minutes or more.

[0027] When the pouched food for retort 11 in the cell unit 14 is heated at high temperature by the heating medium 41 and sterilized at the same time, the filled contents boil, the internal pressure rises, and the food expands, but because it is restrained from above and below by the pair of cells 12a, 12b, no pressure is applied to the heat-sealed portion of the pouched food for retort 11, and the bag can be effectively prevented from breaking. In particular, because the inner peripheral edge of the heat-sealed portion of the cell body 1 is sandwiched between the pair of cells 12a, 12b, the pressure of the contents does not directly reach the heat-sealed portion (inner edge), and the bag can be effectively prevented from breaking at the heat-sealed portion. All of these operations are carried out under atmospheric pressure.

[0028] In addition, since the pouched food for retort pouch 11 is bound by the pair of cells 12a, 12b, it is strongly attached to the wall surfaces of the cells 12a, 12b (surfaces in contact with the pouched food for retort pouch 11) and becomes three-dimensional when heated at high temperature. Therefore, if the wall surfaces of the cells 12a, 12b are engraved with a company name, product name, or the like, the engraving can be transferred to the pouched food for retort pouch 11, which is an advantage as it becomes part of the design.

[0029] After the heat sterilization process, the cell unit device 3 is lifted and transported to a cooling process. Prior to this, it is preferable to remove the heating medium 41 adhering to the cell unit device 3 (cell unit 14) by, for example, blowing air onto it.

[0030] (cooling process) The cooling step is performed by using a cooling bath 5 to immerse the cell units 14 after heat sterilization in a cooling medium 51, such as water, filled in the cooling bath 5. The cell units 14 are cooled by the cooling medium 51 while being immersed in the cooling bath 5 and moving sequentially. The temperature of the cooling medium 51 in the cooling bath 5 is 50°C or less, and preferably 40°C or less. Although only one cooling bath 5 is provided in FIG. 5, a plurality of cooling baths 5 with different temperatures may be provided in series. For example, it is preferable to configure the first cooling bath 5 as a 50°C region and the second cooling bath 5 as a 20°C region, as appropriate. The cooling medium 51 filled in the cooling bath 5 may be any medium other than water as long as it can be kept at 50°C or less.

[0031] After cooling, the cell unit device 3 is lifted and the cell unit 14 is removed from the cooling bath 5. At this time, it is preferable to remove the adhering cooling medium 51 by, for example, blowing air onto the cell unit device 3 and the cell unit 14. By removing each cell body 1 of the cooled cell unit 14 from the accommodation space 31 and further removing the pair of cells 12a, 12b from the cell body 1, the heat-sterilized retort pouch food product can be recovered. [Industrial Applicability]

[0032] The method for producing a retort pouch food product according to the present invention, which involves heat sterilization under atmospheric pressure, can be suitably used not only for producing retort pouch food products in which cooked foods such as curry and stew are packaged, but also for producing food products that require heat sterilization (boiling sterilization) treatment at 100°C or less, and for producing various other products other than food for which heat sterilization is effective. [Explanation of symbols]

[0033] 1 Cell body 11 Retort pouch foods 11a Vertical seal part 11b Horizontal seal part 12a cell (lower cell) 12b cell (upper cell) 13 Recess 14 Cell Unit 2 Filling and packaging machine 21 Conveyor 3 Cell unit device 31 Storage Space 32 Support part 33 Upper wall 34 Protrusion 4. Heating Bath 41 Heating medium 5 Cooling Bath 51 Cooling medium

Claims

1. A method for producing a retort pouch food product, comprising: forming a pouch by heat-sealing a strip-shaped multilayer packaging film in a filling and packaging machine; filling and packaging a content in the pouch; and then heat-sterilizing the pouch to produce a retort pouch food product, comprising the steps of: a cell body forming step of individually housing the retort pouch foods continuously produced by a filling and packaging machine in a pair of metal cells to form a cell body; A heat sterilization step in which the cell body is immersed in a heating bath filled with a heating medium having a boiling point of over 100°C, and the contents of the retort pouch food contained in the cell body are heated under atmospheric pressure; a cooling step of immersing the cell body heat-sterilized in the heat sterilization step in a cooling bath at 50° C. or less to cool the contents of the retort pouch food; The method for producing a retort pouch food product is characterized in that the retort pouch food product is continuously produced through the steps of:

2. 2. The method for producing a retort pouch food product according to claim 1, wherein a recess is provided on at least one of the mutually opposing surfaces of the pair of cells, and the retort pouch food is accommodated in the recess.

3. 3. The method for producing a retort pouch food product according to claim 1 or 2, wherein the retort pouch food is sealed between the pair of cells by having an outer peripheral edge portion including at least a heat-sealed portion sandwiched between the outer peripheral portions of the pair of cells.

4. 3. The method for producing a retort pouch food product according to claim 1, wherein the retort pouch food is sandwiched between a pair of the cells with a predetermined gap therebetween at an outer peripheral edge portion including at least an inner edge portion of a heat-sealed portion.

5. 3. The method for producing a retort pouch food product according to claim 1 or 2, further comprising a stacking step between the cell body forming step and the heat sterilization step, in which a plurality of the cell bodies are stacked to form a unit, and the cell bodies are moved unit by unit.

6. 3. The method for producing a retort pouch food product according to claim 1, wherein the heating medium is one or more oils selected from glycerin, propylene glycol and 1,3-butylene glycol, saline, or a mixed liquid of the oil and water.

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