JPS6248344A - Production of box lunch - Google Patents

Abstract

PURPOSE:To produce an extremely sanitary box lunch having excellent preservability in high efficiency, by filling cooked rice and subsidiary foods in a lunch box, transferring the box on a specific conveyor to scrape off the projected part of the rice, etc., removing air, quenching with liquid nitrogen and sealing the product. CONSTITUTION:Cooked rice 7 and subsidiary food 8 such as croquette, broiled fish, etc., are filled in the respective parts of a lunch box 1 composed of the rice-filling part 2 partitioned by the rice-filling part wall 4 and the subsidiary food filling part 3 partitioned by the subsidiary food filling part wall 5. The filled lunch box 1 is placed in the corresponding hollow 9 of a conveyor 10 and transferred. The excess rice projected from the box is scraped off with a scraper plate 12 in the zone 11 to flatten the surface of the cooked rice, and the surface of the subsidiary food is flattened if necessary by pressing, etc. The lunch box 1 is introduced into the preliminary chamber 13 evacuated with a vacuum pump 14 and supplied with N2 gas through a pipe 15 furnished with a valve and then into a sealing and cooling chamber 17 supplied with liquid nitrogen through the liquid nitrogen supplying pipe 20. The lunch is cooled quickly to <=-8 deg.C, the unfilled part in the lunch box is filed with N$2 gas, and the box is sealed with a film 19 with a vertically movable sealing apparatus 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for producing a boxed lunch that can be stored for a long period of time and can be prevented from deterioration such as deterioration in taste, spoilage, or alteration.

Background of the invention and its problems There are many opportunities to eat bento at work or while traveling. This bento generally consists of cooked rice, which is the staple food, and a side dish, which is a side dish. However, due to the risk of food poisoning, especially in the summer, bento boxes must be served within a certain period of time, such as within six hours, after being produced.

In this way, in order to serve a bento within a certain period of time, it means that the bento must be manufactured within a certain period of time calculated from the eating time.For example, if a bento is eaten at noon, This means that this bento box must be manufactured between 7 a.m. and 12 a.m. within a certain period of time (for example, within 6 hours) from noon. Increased costs, along with tS<, were one of the reasons for hindering production.

Therefore, even if bento boxes are manufactured before the day of delivery, there is no need to worry about deterioration in taste, deterioration, or spoilage of the bento boxes, and therefore, there is no risk of food poisoning. It is expected that this will save money and increase the chances of eating boxed lunches.

In view of the above-mentioned points, the present inventor has devised a method for producing a bento box that does not cause the risk of deterioration in taste, deterioration, or spoilage of the bento box even if it is manufactured before the day of eating the bento box, and therefore does not cause any risk of food poisoning. As a result of extensive research, we discovered that all that is required is to quickly cool the lunch container to a specific temperature and seal it with a film, as well as fill the unfilled space of the lunch container with an inert gas such as nitrogen gas. He discovered that when filling the unfilled space of a lunch container with nitrogen gas, it is important to ensure that the rice serving as a staple food served in the lunch container does not rise above the wall of the rice serving section. The invention was completed.

OBJECTS OF THE INVENTION As mentioned above, the present invention provides a method for producing bento lunches that have excellent preservability and are free from deterioration such as deterioration of taste, spoilage, or spoilage even when the bento lunches are stored for a long period of time. It is intended to.

Summary of the Invention The method for manufacturing a bento box according to the present invention includes placing cooked rice and a side dish in a rice serving part and a side dish serving part of a lunch container, respectively;
The bento container is stored in a concave portion of a conveyor having a concave portion corresponding to the bento container, and while being transferred, the raised portion from the wall of the rice serving section is scraped off, and then air is sucked and nitrogen gas is blown into a preliminary chamber. After passing through the temperature, the lunch container is heated to -8℃ in a sealed cooling chamber into which liquid nitrogen is introduced.
It is characterized by sealing with a film and filling the unfilled space of the lunch container with nitrogen gas obtained by vaporizing the liquid nitrogen while cooling to the humidity below.

In the present invention, the side dish that is a side dish for a bento box may be placed after the cooked rice is placed in the side dish serving portion of the bento container, or after the raised portion of the cooked rice is scraped off.

The bento boxed lunch obtained by the method for manufacturing a boxed lunch according to the present invention has excellent preservability, so that it is possible to improve the efficiency of the manufacturing process and is also extremely hygienic. Further, the nitrogen gas filled in the seal cooling chamber can be used repeatedly.

DETAILED DESCRIPTION OF THE INVENTION The manufacturing process of the bento box according to the present invention will be explained below with reference to the drawings.

First, the bento container 1 used in the manufacturing process of the bento according to the present invention includes a rice serving section 2 for serving cooked rice, which is a staple food, and a side dish serving section 2 for serving side dishes, salads, etc. 3, the main food serving part 2 is defined by a rice serving part wall 4 which is provided so as to rise from the bottom wall of the container 1, and the side food serving part 3 is similarly defined by the rice serving part wall 4 which is provided so as to rise from the bottom wall of the container 1. It is defined by a side food serving section wall 5 which is provided so as to rise from the bottom wall. The rice serving portion wall 4 and the side food serving portion wall 5 are formed at approximately the same height as the side wall 6 of the container 1.

Such a lunch container 1 is an automatic rice serving device (not shown).
The cooked rice 7 is placed on the staple food serving portion 2 of the container 1 by hand or manually by an operator. Similarly, a side dish 8 such as croquettes or grilled fish is placed on the side dish serving portion 3 of the bento container 1. This arrangement of side dishes may be performed by an automatic side food serving device, or may be performed manually by an operator.

The bento container 1 in which the cooked rice 7 and the side dishes 8 are arranged as described above is stored in the recess 9 of the conveyor 10 having a recess 9 corresponding to the bento container, and is transferred on the conveyor 10 so that the surface of the cooked rice is flat. At this point, the portion of the rice that has risen above the wall 4 of the rice serving portion is scraped off so that the portion that has risen above the wall 4 and side wall 6 of the rice serving portion of the lunch container 1 does not exist. do. Regarding the side dish 8, be sure to prepare the side dish 8 in advance so that it does not rise above the wall 5 of the side dish serving part, or if it rises above the wall 5 of the side dish serving part, press it down. This prevents the side food 8 from being raised higher than the side food serving part wall 5.

To scrape off the rice that has risen above the rice plate wall 4, place the spatula-shaped scraping plate 12 above the conveyor 10 at a height such that it touches the rice plate 4 wall 4 and side wall 6 of the lunch container 1. That is, it is provided at a height such that it touches the top surface of the conveyor, and the scraping plate 12 is used to scrape off the rice that has risen from the rice serving portion wall 4 of the lunch box that has been transferred by the conveyor 10. The rice scraped off by the scraping plate 12 is returned to the rice bin by the intermittent movements of the scraping plate 12 toward the rice bin.

As described above, the cooked rice 7 and the side dish 8 are placed in the lunch container 1 so that they do not rise above the rice serving part wall 5 and the side dish serving part wall 6, respectively. The preliminary chamber 13 was filled with nitrogen gas.
passed. A vacuum pump 14 for sucking air and a valved conduit 15 for introducing nitrogen gas into the preliminary chamber are connected to the preliminary chamber 13. Further, it is preferable to provide a sealing member 16 at the entrance to the preliminary chamber 13 in order to keep the preliminary chamber 13 in a sealed state.

In this pre-chamber 13, the lunch container 1 can be pre-cooled, and for this purpose, a cooling device (not shown) is installed in the pre-chamber 13.
Alternatively, cold nitrogen gas obtained by vaporizing liquid nitrogen obtained in a seal cooling chamber, which will be described later, may be introduced into the preliminary chamber 13 through a conduit 15.

Next, the lunch container 1 that has passed through the preliminary chamber 13 is guided into the sealed cooling chamber 17 into which liquid nitrogen is introduced via the liquid nitrogen introduction pipe 20, and the lunch container is kept at -8°C or lower in this sealed cooling chamber 17. While rapidly cooling preferably to a temperature of -12° to -30°C, the unfilled space of the lunch container 1 is filled with nitrogen gas obtained by vaporizing the liquid nitrogen, and the upper opening of the lunch container 1 is moved up and down. Seal with a film 19 by means of a possible sealing device 18 . When the lunch container 1 is rapidly cooled to a temperature of -8° C. or lower using liquid nitrogen, cell membrane damage due to freezing is prevented when the cooked rice 7 and the side dish 8 are frozen, and excellent taste can be maintained.

Note that the preliminary chamber 13 and the seal cooling chamber 17 are continuously provided so as to be in contact with each other.

Because liquid nitrogen is used for cooling, conveyor 1
It is preferable that the parts that come into direct contact with liquid nitrogen, such as carbon steel, are made of a material having low temperature durability such as high manganese steel.

As the film 19 for sealing the lunch container 1, a film having low oxygen permeability and excellent safety is preferable, and specifically, polyethylene film, polypropylene film, polyester film, pullulan film, etc. are used. Among these, pullulan film sold by Hayashibara Biochemical Research Institute is particularly preferred. This pullulan film is composed of a water-soluble, non-gel-forming viscous polysaccharide, and has the characteristics of being edible and having a low oxygen permeability. have. Moreover, since this pullulan film can be tightly adhered to the lunch container 1,
It also has the advantage of excellent sealing properties. Furthermore, if the lunch box container 1 is sealed with this pullulan film, there is an advantage that the effort of removing the film when heating the lunch box is saved.

In the present invention, cooked rice 7 and side dishes 8 are placed in the lunch container 1 so as not to bulge out from the rice serving part wall 4 and the side food serving part wall 5. However, if the cooked rice 7 etc. are higher than the rice serving part wall 4, If you try to seal the bento container 1 while it is still raised, when the bento container 1 is stored in the recess 9 of the conveyor 10 and transferred to the preliminary chamber 13, cooked rice may be stuck to the wall or the sealing member 16 at the entrance of the preliminary chamber 13. It is undesirable to wear multiple clothes, and the film that seals the lunch container 1 may deform or shrink due to the moisture contained in the cooked rice or the heat, and in some cases pinholes may occur, allowing oxygen to enter the inside of the lunch container 1. Therefore, it is undesirable.

It is preferable that the bento boxed lunch thus produced is then stored in a refrigeration chamber maintained at a temperature of -15°C or lower, preferably -15 to -30°C.

In the method for producing a bento box according to the present invention, cooked rice and side dishes are placed in the rice serving section and the side dish serving section of a lunch container, respectively, and the lunch container is placed on a conveyor having a concave portion corresponding to the bento container. While storing the rice in a recess and transferring it, scrape off the raised part from the wall of the rice serving area, and then pass through a preliminary chamber where air is sucked and nitrogen gas is blown into it, followed by seal cooling where liquid nitrogen is introduced. Place the lunch container indoors.
It is characterized by sealing with a film and filling the unfilled space of the lunch box with nitrogen gas obtained by vaporizing the liquid nitrogen while cooling it to a temperature below ℃, so that the lunch box that can be made for 1q has a long shelf life. Are better. Therefore, it is possible to improve the efficiency of the bento manufacturing process, and it is also extremely hygienic.

In addition, the lunch containers are stored in the recess of the conveyor, which has a recess that corresponds to the lunch container, and are led to the preliminary chamber where air is removed. Therefore, oxygen does not enter the seal cooling chamber, and therefore the seal The nitrogen gas filled in the cooling chamber can be reused as nitrogen gas introduced into the preliminary chamber 13, which is economically advantageous.

The present invention will be specifically explained below using test examples.

According to the present invention, after the cooked rice 7 and the side dishes 8 are arranged in the lunch container 1, the lunch container is cooled to a temperature of -20°C with liquid nitrogen, nitrogen is filled in the lunch container 1, and the container is sealed with pullulan film. did. When the bento prepared in this way was stored in a refrigerator kept at -20°C for 6 months and then taken out and warmed up, it had the same excellent taste as a freshly made bento. Ta. Moreover, no change in the color of the staple food or side food was observed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a lunch container used in the present invention,
FIG. 2 is a schematic explanatory diagram of the method of the present invention. 1... Lunch container, 2... Rice serving part, 3... Side dish serving part, 4... Rice serving part wall, 5... Side dish serving part wall, 6... Lunch box Container side wall, 7...Rice, 8...Side dish, 9...Recess, 10...Conveyor, 11...Rice rice surface flattening area, 13...Preliminary stage, 17...Seal Cooling chamber, 19... film, 20... liquid nitrogen conduit.

Claims (3)

[Claims] (1) Serve cooked rice and side dishes in the rice serving part and the side dish serving part of the lunch container, respectively, and store the lunch container in the recess of the conveyor that has a recess corresponding to the lunch container and transfer it to the rice serving part. After scraping off the part that rose from the wall, the lunch container was passed through a preliminary chamber where air was sucked and nitrogen gas was blown in, and then the lunch container was placed at -8℃ or lower in a sealed cooling chamber where liquid nitrogen was introduced. 1. A method for manufacturing a lunch box, which comprises sealing with a film while cooling the lunch container to a temperature, and filling an unfilled space of the lunch container with nitrogen gas obtained by vaporizing the liquid nitrogen. (2) The manufacturing method according to claim 1, wherein the cooling temperature of the lunch container is in the range of -12 to -30°C. (3) Claim 1, characterized in that the obtained bento is further stored in a freezer maintained at -15°C or lower.
The method described in section.