Cooling foam and freshness-keeping foam

Abstract

This cooling foam and this freshness-keeping foam are used for reducing the weight of freight during transportation of fresh products, and keeping the freshness of fresh products. When transporting a fresh product, transportation is performed by having this cooling foam placed in a packing box together with the fresh product. This cooling foam is obtained by adding a foaming agent and a shape retention agent to a liquid which becomes a cooling medium for fresh products, and foaming the liquid. The liquid which becomes a cooling medium for fresh products preferably accounts for at most 99.80% of the weight of the liquid to which the foaming agent and the shape retention agent are added, and preferably accounts for at least 87.00% of the weight of the liquid to which the foaming agent and the shape retention agent are added.

Description

Cooling and freshness-keeping foam

[0001] The present invention relates to cooling and freshness-preserving foams, and more particularly to cooling and freshness-preserving foams that are used in the transportation of perishable goods and are foam-shaped.

[0002] When transporting fresh products such as fresh fish and vegetables, it is necessary to transport them in a state in which the freshness of the fresh products is maintained as much as possible. In order to maintain the freshness of the fresh products, methods of maintaining the temperature of the fresh products at a relatively low temperature are used. For example, when transporting fresh fish (fresh products), the fresh fish is packed together with a cooling material (cooling medium) such as ice water (ice + water) in a packaging box formed from a material with high heat retention (e.g., a foam material), thereby maintaining the low temperature of the fresh fish (see, for example, Patent Document 1).

[0003] In addition, in order to prevent deterioration of the freshness of fresh fish (perishable goods), a method is known in which ice made using alkaline electrolyzed water and alkaline electrolyzed water are packed together with the fresh fish in a packaging box, thereby suppressing spoilage due to oxidation of the fresh fish with the alkaline electrolyzed water, thereby maintaining the freshness of the perishable goods (see, for example, Patent Document 2).

[0004] Japanese Patent Application Laid-Open No. 2020-083371

[0005] Patent No. 5692715

[0006] However, when transporting fresh produce using the methods of Patent Documents 1 and 2, a large amount of ice and water is placed in the packing box, which means that the weight of the ice and water is added to the weight of the fresh produce itself, resulting in a problem of an increased weight of the packing box. In particular, since there is a limit to the weight of luggage that can be loaded on transport trucks, cargo planes, etc., if the weight of the packing box is heavy, there is a risk that the number of packing boxes that can be loaded will be limited even if there is sufficient space in the luggage compartment.

[0007] In addition, general shipping costs vary depending on the weight. As mentioned above, when putting ice water in a packing box, the shipping cost is calculated based on the weight of the fresh product itself plus the weight of the ice water. This has led to the problem of high shipping costs.

[0008] Furthermore, when ice water is placed in a packing box and transported, there is a risk that the ice may cause scratches or dents on the exterior of the fresh produce, which can lead to a deterioration in the freshness of the fresh produce and a decrease in the commercial value of the fresh produce.

[0009] The present invention has been made in consideration of the above problems, and its objective is to provide cooling foam and freshness-preserving foam that can reduce the weight of the transported goods and preserve the freshness of the fresh goods when transporting them.

[0010] In order to solve the above problems, the cooling foam of the present invention is characterized by being made by adding a foaming agent and a shape-retaining agent to a liquid that serves as a cooling medium for fresh produce and foaming it.

[0011] In the above-mentioned cooling foam, the liquid may account for 99.80% or less by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0012] In the above-mentioned cooling foam, the liquid may account for 87.00% or more by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0013] In the cooling foam described above, the liquid may be water.

[0014] In the above-mentioned cooling foam, the shape retaining agent may account for 0.01% or more by weight of the total weight of the liquid, the foaming agent, and the shape retaining agent.

[0015] In the above-mentioned cooling foam, the weight of the shape retaining agent may be 3.00% or less based on the total weight of the liquid, the foaming agent, and the shape retaining agent.

[0016] In the cooling foam described above, the shape-retaining agent may be a thickening polysaccharide.

[0017] In the above-mentioned cooling foam, the foaming agent may account for 0.20% or more by weight of the total weight of the liquid, the foaming agent, and the shape-retaining agent.

[0018] In the above-mentioned cooling foam, the foaming agent may account for 5.00% or less by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0019] In the cooling foam described above, the foaming agent may be a non-ionic surfactant.

[0020] The ratio of the weight of the foaming agent to the weight of the foaming agent and the shape retaining agent added to the liquid may be twice the ratio of the weight of the shape retaining agent to the weight of the foaming agent and the shape retaining agent added to the liquid.

[0021] The freshness-preserving foam according to the present invention is characterized in that it is produced by adding a foaming agent and a shape-retaining agent to a liquid for sterilizing fresh produce and foaming it.

[0022] In the above-mentioned freshness-keeping foam, the liquid may account for 99.80% or less by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0023] In the above-mentioned freshness-keeping foam, the liquid may account for 87.00% or more by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0024] In the above-mentioned freshness-keeping foam, the liquid may be electrolyzed water.

[0025] In the above-mentioned freshness-keeping foam, the shape retaining agent may account for 0.01% or more by weight of the liquid plus the foaming agent and the shape retaining agent.

[0026] The above-mentioned shape retaining agent may account for 0.04% or more by weight of the total weight of the liquid, the foaming agent, and the shape retaining agent.

[0027] In the above-mentioned freshness-keeping foam, the shape retaining agent may account for 3.00% or less by weight of the total weight of the liquid, the foaming agent, and the shape retaining agent.

[0028] In the above-mentioned freshness-keeping foam, the shape-retaining agent may be a thickening polysaccharide.

[0029] In the above-mentioned freshness-keeping foam, the foaming agent may account for 0.20% or more by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0030] In the above-mentioned freshness-keeping foam, the foaming agent may account for 5.00% or less by weight of the liquid plus the foaming agent and the shape-retaining agent.

[0031] In the above-mentioned freshness-keeping foam, the foaming agent may be a nonionic surfactant.

[0032] The freshness-preserving foam according to the present invention is characterized in that it is produced by adding a foaming agent, a shape-retaining agent and a moisturizing agent to a liquid for sterilizing fresh produce and foaming it.

[0033] In the above-mentioned freshness-keeping foam, the moisturizing agent may include at least one of sorbitol, hyaluronic acid, and sodium hexametaphosphate.

[0034] By using the cooling foam and freshness-preserving foam according to the present invention, it is possible to reduce the weight of the goods being transported when transporting fresh produce, and also to preserve the freshness of the fresh produce.

[0035] 1 is a table showing the proportions of foaming agents, shape retaining agents, etc. in chilled foam and the test results of each test. 2 is a table showing the proportions of foaming agents, shape retaining agents, etc. in freshness-retaining foam and the test results of each test. 3 is a graph showing the temperature change of chilled foams A1 to A3 shown in the table of FIG. 1 when chilled foams A1 to A3 are cooled to -18°C and then left in a temperature environment of 20°C.

[0036] The cooling foam and freshness-preserving foam according to the present invention will be described in detail below with reference to the drawings.

[0037] [Overview of Chilled Foam and Freshness-Preserving Foam] The chilled foam and freshness-preserving foam (sterilizing foam) of the present invention are foam materials used to preserve the freshness of perishable goods such as fresh fish and vegetables. The chilled foam and freshness-preserving foam are composed of at least a liquid medium for preserving freshness, a foaming agent for foaming the liquid medium (improving foaming) to form a foam shape, and a shape retainer for maintaining the foam shape (prolonging the foam life). The chilled foam and freshness-preserving foam are generated by stirring and foaming the liquid medium, the foaming agent, and the shape retainer. Note that in the embodiments, "fresh goods" refers to vegetables, fruits, fresh fish, meat, etc., and generally refers to foods that are required to be fresh (perishable). Furthermore, "fresh goods" is not limited to foods, but can also include products whose commercial value varies depending on their freshness, such as fresh flowers.

[0038] As described above, cooling foam and freshness-preserving foam are similar in that they are composed of at least a liquid medium, a foaming agent, and a shape-retaining agent, and are used in a foamed form by a foaming process. However, cooling foam is a cooling agent (cooling medium) used to prevent freshness deterioration due to a rise in temperature of fresh produce, and is packed into a packaging box for the fresh produce in a cooled state after foaming. On the other hand, freshness-preserving foam is a sterilizing foam used to cover the outer surface of fresh produce in order to prevent the intrusion and growth of bacteria (germs) in the fresh produce, and is not necessarily cooled after foaming.

[0039] [Regarding the generation of cooling foam] The generation of cooling foam will be described. In the cooling foam according to the embodiment, water is used as the liquid medium. Liquid media (cooling agents, cooling media) for fresh produce are packaged together with the fresh produce and are relatively widely used in the market. For this reason, it is preferable that the liquid medium (cooling agent, cooling media) is inexpensive, easily available in large quantities in the market, and a suitable example of such a liquid medium is ordinary tap water. Tap water (water) is not only inexpensive and readily available, but is also a liquid medium that is safe for the human body. Therefore, even if the liquid medium (water) comes into direct contact with or enters the body during the cooling foam generation process, there is no risk of harm to the human body.

[0040] In the cooling foam of the present embodiment, a nonionic surfactant is used as an example of a foaming agent. Nonionic surfactants are surfactants that contain hydrophilic groups such as hydroxyl groups (-OH) or ether bonds (-O-) that do not dissociate into ions (i.e., do not become ions) when dissolved in water. Nonionic surfactants can be divided into "ethylene oxide (polyethylene glycol) type" and "polyhydric alcohol type." Polyhydric alcohol types are commonly used as foaming agents for cooling foam (and also for freshness-preserving foam, as described below). Polyhydric alcohol types combine hydrophobic groups such as higher fatty acids with polyhydric alcohols such as glycerin, sorbitol, and sucrose as hydrophilic groups. Polyhydric alcohol types have multiple hydroxyl groups (-OH), which are primarily responsible for the hydrophilic properties of the product. By forming ester bonds between the hydroxyl groups (-OH) of polyhydric alcohol types and higher fatty acids, they can be used as additives with excellent safety. Such ester-type (ester bond) surfactants are approved as food additives due to their excellent safety. Examples of known food additives include glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, and propylene glycol fatty acid esters, which can be used as foaming agents for cooling foam (freshness-preserving foam, which will be described later).

[0041] In the cooling foam according to the embodiment, a polysaccharide thickener made from polysaccharides is used as an example of a shape retaining agent. Thickeners are commonly used as food additives to impart viscosity, and there is no risk of harm to the human body if they enter the body. Known examples of thickeners include pectin made from citrus fruits or apples, alginic acid extracted from algae, carrageenan, guar gum extracted from the fruit of legumes, locust bean gum, tamarind gum, xanthan gum produced by microorganisms, and curdlan.

[0042] Furthermore, in the cooling foam according to the embodiment, a humectant is added to the liquid medium, foaming agent, and shape-retaining agent described above. When the cooling foam is used as a cooling medium for fresh produce, as described below, the cooling foam is used in a sealed state in a plastic bag, so adding a humectant to the cooling foam does not impart a moisturizing effect to the fresh produce. On the other hand, in the freshness-preserving foam described below, adding a humectant can improve the freshness-preserving effect of the fresh produce. When both the cooling foam and the freshness-preserving foam are produced, it is desirable to share the components of the cooling foam and the freshness-preserving foam as much as possible in order to reduce production costs and production burden. In the cooling foam according to the embodiment (cooling foam A2 and cooling foam A3 described below), a case will be described in which a humectant is added to the cooling foam in order to share the components with the freshness-preserving foam. Note that the humectant is not an essential component of the cooling foam, so it can be omitted.

[0043] The moisturizer according to the embodiment is water-soluble because tap water (water) is used as the liquid medium. Furthermore, the moisturizer used is one that is highly safe for the human body. Examples of moisturizers that can be used include sorbitol (D-sorbitol), hyaluronic acid, and sodium hexametaphosphate. Sorbitol is also used as a food additive and is a natural sugar alcohol derived from potato starch and corn starch. Therefore, even if sorbitol enters the body, there is no risk of it harming the human body. Furthermore, the moisturizer does not need to contain all of the components, such as sorbitol (D-sorbitol), hyaluronic acid, and sodium hexametaphosphate; it is sufficient to contain at least one of them.

[0044] To generate the cooling foam, tap water (water) as the liquid medium, a nonionic surfactant as the foaming agent, a thickening polysaccharide as the shape-retaining agent, and sorbitol or another humectant are mixed and stirred in the proportions described below, and then foamed using a foaming machine. The cooling foam generated by the foaming process is placed in a plastic bag and sealed to create a cooling foam pack (this cooling foam pack is referred to as a "cooling foam bag"). The cooling foam bag is cooled to a temperature suitable for low-temperature storage of fresh produce before use. By placing the cooling foam bag cooled to the appropriate temperature in a packaging box together with the fresh produce and packaging it, it is possible to suppress the temperature rise of the fresh produce and prevent deterioration of the fresh produce.

[0045] Three types of cooling foam were produced as cooling foams according to the embodiment: cooling foam A1, cooling foam A2, and cooling foam A3, as shown in Figure 1. The total weight of each of cooling foams A1 to A3 before foaming treatment (referred to as "weight before foaming") is set to 100.00%, and the weight percentages of each component (weight percent concentration) are as follows: Cooling foam A1 is 99.79% water, 0.20% foaming agent, 0.00% humectant, and 0.01% shape retainer.

[0046] Cooling foam A2 is 93.80% water, 2.00% foaming agent, 3.20% humectant, and 1.00% shape retainer. Cooling foam A3 is 87.00% water, 5.00% foaming agent, 5.00% humectant, and 3.00% shape retainer.

[0047] [Regarding the generation of freshness-preserving foam] Next, the generation of freshness-preserving foam will be described. The freshness-preserving foam according to the embodiment uses a liquid medium with a bactericidal effect. Electrolyzed water is used as an example of a liquid medium with a bactericidal effect. Electrolyzed water has a bactericidal effect on food, a cleaning and disinfecting effect, and a deodorizing effect, and is low-cost. Electrolyzed water can be easily used in the same way as tap water, making it ideal as a bactericide for fresh produce and the like. Known types of electrolyzed water include acidic electrolyzed water (hypochlorous acid water) and electrolyzed hypochlorous water.

[0048] Acidic electrolyzed water is an acidic disinfectant obtained by electrolyzing a sodium chloride solution (brine) or hydrochloric acid. It is widely used for food sterilization, etc., and disinfects bacteria and viruses by oxidizing them. The hypochlorous acid contained in acidic electrolyzed water has a small molecular size and is electrically neutral, so it penetrates the cell walls of bacterial cells and directly oxidizes the internal cellular tissue, such as nucleic acids, thereby exerting a powerful disinfecting effect. Specifically, acidic electrolyzed water (hypochlorous acid water) has an effective bactericidal effect against Salmonella, Aspergillus niger, MRSA, Escherichia coli, Streptococcus, influenza virus, norovirus, spore-forming bacteria (Bacillus cereus, Clostridium perfringens, Clostridium botulinum), etc.

[0049] Electrolyzed hypochlorous acid water is bactericidal electrolyzed water (sodium hypochlorite water generated by electrolysis) whose main component is weakly alkaline sodium hypochlorite. It is compatible with food additives, exhibits excellent disinfecting effects even at low concentrations, and can be used directly on food ingredients. Furthermore, electrolyzed hypochlorous acid water has a neutral pH, a low chlorine odor, and decomposes quickly after use, making it gentle (less damaging) to people, food ingredients, and the environment. Furthermore, because electrolyzed hypochlorous acid water can be automatically generated using an electrolysis device, stable quality (concentration control) can be ensured at a relatively low cost. Electrolyzed hypochlorous acid water is often used over running water (flowing over). While both acidic electrolyzed water (hypochlorous acid water) and electrolyzed hypochlorous acid water can be used as the liquid medium for freshness-preserving foam, the freshness-preserving foam of the embodiment uses electrolyzed hypochlorous acid water, which has a relatively long-lasting bactericidal effect.

[0050] The freshness-keeping foam also contains the foaming agent, shape retaining agent, and moisturizing agent described in the production of cooling water. The foaming agent, shape retaining agent, and moisturizing agent contained in the freshness-keeping foam are the same as those described in the cooling foam. As already explained, the foaming agent, shape retaining agent, and moisturizing agent used in the cooling foam and freshness-keeping foam are highly safe for the human body, and there is no risk of harm if any of them attached to fresh produce enters the human body.

[0051] As will be described later, the freshness-preserving foam is stored in a packaging box so as to cover the outer surface of fresh produce such as fresh fish, and by adding a humectant to the freshness-preserving foam, it is possible to moisturize the surface of the fresh fish, etc. By maintaining the moisture on the surface of the fresh fish, etc., it is possible to effectively prevent the generation and invasion of bacteria, etc. into the fresh fish. Therefore, by using a freshness-preserving foam in which a humectant has been added to electrolyzed hypochlorous water, it is possible to further enhance the sterilizing effect, and it is possible to more effectively maintain the freshness of fresh fish, etc.

[0052] As the freshness-preserving foam according to the embodiment, the above-mentioned electrolytic hypochlorous water (sterilizing water), foaming agent, shape-retaining agent, and moisturizing agent were mixed and foamed to produce three types of foam materials: freshness-preserving foam B1, freshness-preserving foam B2, and freshness-preserving foam B3, as shown in Figure 2. The total weight of each freshness-preserving foam B1 to B3 before the foaming process ("pre-foaming weight") is 100.00%, and the weight percentages of each component (weight percent concentration) are as follows: Freshness-preserving foam B1 is 99.59% electrolytic hypochlorous water (sterilizing water), 0.20% foaming agent, 0.20% moisturizing agent, and 0.01% shape-retaining agent.

[0053] Freshness-keeping foam B2 is 94.70% electrolytic hypochlorous water (sterilizing water), 2.00% foaming agent, 3.20% moisturizing agent, and 0.10% shape retainer. Freshness-keeping foam B3 is 87.00% electrolytic hypochlorous water (sterilizing water), 5.00% foaming agent, 5.00% moisturizing agent, and 3.00% shape retainer.

[0054] [Comparison of Cooling Foam] In comparing cooling foams A1 to A3 according to the embodiments, a case will be described in which the object (perishable product) to be cooled using cooling foam is fresh fish. Fresh fish is typically transported by packaging the fish in a packaging box containing ice water (ice and water), and maintaining the internal temperature of the packaging box at, for example, 0°C or below. To maintain a temperature below 0°C, temperature control is generally performed using a refrigerated container, but there are also many situations in which the packaging box must be temporarily left in a room temperature environment due to stacking, loading, unloading, and the like during transportation. Even in such cases, to prevent deterioration of the freshness of the fresh fish, it is necessary to maintain the temperature of the fresh fish (cooling foam) at 0°C or below for at least three hours, even when the packaging box is left in a room temperature environment.

[0055] FIG. 3 shows the time it takes for the temperature of the cooling foam to reach 0°C when 200 g of cooling foam is placed in a plastic bag (cooling foam bag), cooled to -18°C, and then left in a room temperature environment of 20°C. FIG. 1 also shows the time it takes to reach 0°C (cooling maintenance time). Cooling foam A1 reached 0°C (thawed) in 6 hours, cooling foam A2 reached 0°C (thawed) in 7.5 hours, and cooling foam A3 reached 0°C (thawed) in 8 hours. Since the temperature remained below 0°C for at least 3 hours in all cases, the minimum requirements for a cooling material (cooling medium) for fresh fish were met. Furthermore, the cooling foam to be used can be appropriately selected depending on the transportation period of the perishable product to be cooled. For example, if there is a possibility that the packaging box will be left at room temperature for 7 hours or more during transportation, using cooling foam A2 or A3 instead of cooling foam A1 can ensure sufficient cooling effect.

[0056] The proportion of water (weight percent concentration) constituting the cooling foam is preferably 99.80% or less so that it can be formed into a foam shape by foaming treatment. If the water content is more than 99.80%, it may not be possible to form a proper foam shape even if a foaming agent and a shape-retaining agent are added. On the other hand, if the weight percentage of water is less than 87.00%, the foam may become too elastic, so the water percentage is preferably 87.00% or more.

[0057] The table in Figure 1 shows the results of various tests on cooled foam. The column for cooling maintenance time shows the time it takes for the temperature of cooled foam A1 to A3 to reach 0°C when a cooled foam bag cooled to -18°C as described above is left in a room temperature environment of 20°C. The column for viscosity ... ２ The column for elasticity shows whether or not the foam drips within one minute when the cooled foam A1 to A3 is filled to the brim in a plastic cup and the cup is then turned upside down. The column for elasticity shows whether or not a cylindrical shape (with a base area of ​​15.9 cm) forms on the top of the cooled foam when the cooled foam A1 to A3 is filled to the brim in a plastic cup. ２The column for bubble diameter shows the results of measuring the diameter of the cooled bubbles (bubble diameter) using a microscope.

[0058] When the plastic cup was turned upside down, the foam for Cooled Foam A1 dripped within one minute, so the viscosity column showed "None." Furthermore, as shown in the elasticity column, when a weight was placed on the cup, the weight sank 63 mm. On the other hand, the foam for Cooled Foam A2 and Cooled Foam A3 did not drip within one minute, so the viscosity column showed "Yes." Furthermore, as shown in the elasticity column, the weight sank 19 mm for Cooled Foam A2 and 6 mm for Cooled Foam A3. Comparing Cooled Foam A1 to Cooled Foam A3, it can be determined that Cooled Foam A1 has the lowest viscosity and elasticity, Cooled Foam A2 has a medium viscosity, and Cooled Foam A3 has the highest viscosity and elasticity.

[0059] Even if the viscosity or elasticity is low, the cooling foam can achieve the required cooling effect as long as it can maintain a temperature of 0°C or below for at least three hours. However, by using cooling foam with high viscosity or elasticity as the cooling medium, damage to fresh fish can be reduced compared to when ice water (ice + water) is used as the cooling medium, and there is no risk of the commercial value of the fresh fish being damaged during transportation. Furthermore, if appropriate viscosity and elasticity can be ensured, the shape of the cooling foam can be easily deformed according to the shape of the fresh fish, so the contact area of ​​the cooling foam with the fresh fish (more specifically, the contact area via the vinyl of the cooling foam bag) can be increased, thereby further enhancing the cooling effect of the cooling foam on the fresh fish and maintaining its freshness for a longer period of time.

[0060] If the viscosity and elasticity are too high, it becomes difficult to flexibly deform the shape of the chilled foam to match the shape of the fresh fish, while if the viscosity and elasticity are too low, the effect of the chilled foam in reducing external impacts on the fresh fish (buffering effect) will be poor. For this reason, in the chilled foam according to the embodiment, the weight of the foaming agent relative to the pre-foaming weight is preferably 0.20% or more and 5.00% or less, as shown in Figure 1. Furthermore, in the chilled foam, the weight of the shape retainer relative to the pre-foaming weight is preferably 0.01% or more and 3.00% or less.

[0061] As explained above, if the water content is greater than 99.80%, the proportions of the foaming agent and shape-retaining agent become too low, making it difficult to "form the chilled foam into a foam shape" and "maintain the foam shape." Taking this into consideration, in Chilled Foam A1, the total proportion of water and humectant (cooling medium proportion) is 99.80%, the foaming agent proportion is a minimum of 0.20%, and the shape-retaining agent proportion is a minimum of 0.01%. By blending the foaming agent and shape-retaining agent into the pre-foaming liquid (water + humectant) so as to meet at least these minimum proportions, even in a liquid with relatively low viscosity and elasticity like Chilled Foam A1, it is possible to reduce external impact on the fresh fish compared to using ice water as a cooling medium, and ensure a cooling effect of more than three hours (approximately six hours).

[0062] Furthermore, by appropriately adjusting the proportions of the foaming agent and the shape retaining agent within a range that does not fall below the lower limit of the water proportion (87.00%), the viscosity and elasticity can be suitably adjusted. Therefore, by adjusting the proportions of the foaming agent and the shape retaining agent according to the characteristics of the fresh product, it is possible to produce chilled foam with viscosity and elasticity that is best suited to the object to be cooled (type of fresh product).

[0063] However, if the foaming agent ratio exceeds the upper limit of 5.00% or the shape retaining agent ratio exceeds the upper limit of 3.00%, the viscosity and elasticity of the chilled foam will increase, and the foam will tend to become hard overall. Chilled foam made of such hard foam will have difficulty flexibly deforming to conform to the external shape of the fresh produce, and will have a reduced cushioning effect against external impacts. For this reason, the chilled foam according to the embodiment has an upper limit of 5.00% for the foaming agent ratio and 3.00% for the shape retaining agent ratio, as described above.

[0064] As shown in Figure 1, chilled foam for fresh fish can be produced by setting the foaming agent at approximately 2.00% (e.g., 1.80% to 2.20%) or the shape-retaining agent at approximately 1.00% (e.g., 0.80% to 1.20%). This allows for a relatively long cooling period (7 hours and 30 minutes) and produces a chilled foam (Chilled Foam A2) that is approximately three times more flexible and elastic than Cooled Foam A3 (the sinking of the weight is 6 mm for Cooled Foam A3, compared to 19 mm for Cooled Foam A2). By using Cooled Foam A2 to cool fresh fish, the chilled foam bag can be flexibly bent to conform to the curved surface of the fresh fish and contact it, allowing the fresh fish to be kept at a low temperature. Furthermore, because Cooled Foam A2 has sufficient elasticity, it can function as a cushioning material and prevent external damage to the fresh fish even when external impacts are applied to the fresh fish.

[0065] The characteristics of the cooling foam also change depending on the ratio of the foaming agent to the shape retainer (or the ratio of the foaming agent to the shape retainer). When the ratio of the foaming agent is high compared to the shape retainer, the cooling foam can be easily formed into a foam shape by foaming treatment, but because the amount of shape retainer (compared to the foaming agent) is low, the foam shape may not be maintained for a long period of time. In this case, even if a temperature of 0°C or below can be maintained for a predetermined time (e.g., 3 hours), the foam may collapse before that time has elapsed, turning into water (liquid), and it may become difficult to function as a buffer material.

[0066] In the cooled foams according to the embodiment, the proportions of the foaming agent and shape retaining agent in cooled foams A1 to A3 are adjusted so that the proportion of the foaming agent is higher than the proportion of the shape retaining agent, as shown in Figure 1. In cooled foam A1, the shape retaining agent is 0.01%, while the foaming agent is 20 times that, at 0.20%. In cooled foam A2, the shape retaining agent is 1.00%, while the foaming agent is twice that, at 2.00%. In cooled foam A3, the shape retaining agent is 3.00%, while the foaming agent is approximately 1.67 times that, at 5.00%. In this way, when foaming a foaming agent and a shape retaining agent are added to water to foam, by making the proportion of the foaming agent higher than the proportion of the shape retaining agent, it is possible to maintain the foam shape of the cooled foam.

[0067] The table in Figure 1 shows the bubble diameter of each chilled foam. The bubble diameter of chilled foam A1 is 50 μm, while the bubble diameters of chilled foam A2 and chilled foam A3 are 20 μm. The larger the bubble diameter, the more easily the foam breaks (collapses). Therefore, chilled foam A2 and chilled foam A3, which have a bubble diameter of 20 μm, maintain cooling for a longer period of time and are more likely to maintain viscosity and elasticity than chilled foam A1, which has a bubble diameter of 50 μm. Note that the larger the bubble diameter, the more easily the foam breaks, making it easier to wash away with water or the like. However, in the case of chilled foam, since it is used to cool fresh produce in a plastic bag, it is not necessary to consider the ease of washing away the chilled foam.

[0068] Taking the above points into consideration, the ratio of foaming agent and shape retaining agent in the chilled foam is determined and the chilled foam is produced. The ratio of foaming agent and shape retaining agent varies depending on the type of fresh product for which the chilled foam is to be used. However, comparing chilled foams A1 to A3 in FIG. 1, chilled foam A2 has a relatively long cooling time and sufficient viscosity and elasticity, making it highly versatile. Therefore, it is more preferable to set the ratio of foaming agent to shape retaining agent to 2:1. Furthermore, as mentioned above, the ratio of foaming agent is preferably around 2.00% (e.g., 1.80% to 2.20%), and the ratio of shape retaining agent is preferably around 1.00% (e.g., 0.80% to 1.20%).

[0069] [Comparison of Freshness-Preserving Foams] Freshness-preserving foams B1 to B3 according to the embodiments are compared. When comparing freshness-preserving foams B1 to B3, fresh fish is used as the fresh product, as with cooling foams A1 to A3. While cooling foams are used to maintain the temperature of fresh products at 0°C or below, freshness-preserving foams are used to prevent the growth of bacteria and other contaminants on fresh products. For this reason, freshness-preserving foams are used as sterilizing foams. Furthermore, by imparting a certain degree of viscosity and elasticity to the freshness-preserving foam, it is possible for the freshness-preserving foam to function as a buffer material, similar to cooling foam.

[0070] Freshness-preserving foam is typically stored at room temperature in a plastic bag containing 200 g of freshness-preserving foam (the bag is referred to as a "freshness-preserving foam bag"). However, like a refrigerated foam bag, it can also be stored and used in a cooled state below 0°C (a temperature at which the fluidity of the freshness-preserving foam is not impaired). When transporting fresh produce, a refrigerated foam bag cooled to -18°C is placed on the bottom of a packaging box, a freshness-preserving foam bag is placed on top of it, holes are drilled in the freshness-preserving foam bag, and the fresh produce is placed on top of it, so that the underside of the fresh produce is covered as evenly as possible with the freshness-preserving foam emerging from the holes in the freshness-preserving foam bag. Furthermore, a freshness-preserving foam bag with holes is placed on the top of the fresh produce so that the top surface of the fresh produce is covered as uniformly as possible with the freshness-preserving foam, and then a cooling foam bag cooled to -18°C is placed on top so that the fresh produce is wrapped (sandwiched) from above and below by the cooling foam bag and the freshness-preserving foam (freshness-preserving foam bag), and the fresh produce, freshness-preserving foam and cooling foam are stored in a packing box.

[0071] The weight ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) that constitutes the freshness-preserving foam is preferably 99.60% or less so that it forms a foam shape through foaming treatment. If the electrolyzed hypochlorous water is more than 99.60%, even if a foaming agent and a shape-retaining agent are added, the foam may not form properly. On the other hand, if the ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) is less than 87.00%, the viscosity and elasticity of the foam may become too high. Therefore, it is desirable to set the ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) to 87.00% or more.

[0072] Furthermore, since the freshness-preserving foam is used to cover fresh fish (perishable goods), it is preferable to maintain the foam shape as much as possible. The shape retention time shown in Figure 2 indicates the time until the freshness-preserving foam collapses when the freshness-preserving foam is filled to the top of a 200 ml plastic cup and left at room temperature (20°C). Since the freshness-preserving foam prevents the growth of bacteria by covering the fresh fish (perishable goods) in its foam form, it is preferable to maintain the foam shape during transportation of the fresh fish (perishable goods). The transportation period for fresh goods varies depending on the distance to the destination, but a transportation period of about three days is generally required. If a transportation period of about three days can be ensured, domestic transportation from Tokyo to the northernmost or southernmost tip of Honshu is possible, and international air transportation to Asia is also possible.

[0073] As shown in the shape retention time column of Figure 2, the foam in freshness-preserving foam B1 collapses in one minute. Therefore, even if a freshness-preserving foam is produced using a foaming agent ratio of 0.20% and a shape retaining agent ratio of 0.01%, as in freshness-preserving foam B1, it is difficult to maintain the foam shape for three days. On the other hand, in the case of freshness-preserving foam B2, the foam shape is maintained until the seventh day (or at least until just before the seventh day), so it is possible to cover fresh fish (perishable goods) in the foam shape for at least three days after packaging. Similarly, in the case of freshness-preserving foam B3, the foam shape is maintained until the 30th day (or at least until just before the 30th day), so the freshness-preserving foam can suppress the growth of bacteria and other contaminants on perishable goods, not only during the transportation period of about three days mentioned above, but even when the transportation period is longer than that.

[0074] In order to maintain the shape retention time of the freshness-preserving foam for at least about three days, it is desirable to set the proportion of the shape retaining agent to 0.04% or more. By setting the proportion of the shape retaining agent to 0.04% or more, it is possible to ensure a shape retention time of at least about three days, so that the fresh fish (perishable goods) can be kept covered with foam until the fresh fish arrives at the destination, and it is possible to suppress the growth of bacteria and the like on the fresh fish (perishable goods).

[0075] Similarly to FIG. 1, FIG. 2 also lists information regarding "viscosity," "elasticity," and "bubble diameter." These test details are the same as those for chilled foam. If the viscosity and elasticity are too high, it becomes difficult to cover the fresh fish with the freshness-preserving foam according to its shape. On the other hand, if the viscosity and elasticity are too low, it becomes difficult for the freshness-preserving foam to absorb external impacts applied to the fresh fish. Therefore, in the freshness-preserving foam according to the embodiment, the ratio of the weight of the foaming agent to the pre-foaming weight is preferably 0.20% or more and 5.00% or less. Furthermore, in the freshness-preserving foam, the ratio of the weight of the shape-preserving agent to the pre-foaming weight is preferably 0.01% or more and 3.00% or less. As already explained, if the shape-preserving time of the freshness-preserving foam needs to be maintained for at least three days, it is desirable to set the ratio of the shape-preserving agent to 0.04% or more.

[0076] In addition, by adjusting the ratio of the foaming agent and the shape retaining agent within a range not below the lower limit (87.00%) of the ratio of electrolyzed hypochlorous acid water (electrolyzed water, sterilizing water), viscosity and elasticity can be suitably increased. Therefore, by adjusting the ratio of the foaming agent and the shape retaining agent according to the characteristics of the fresh product, it is possible to produce a freshness-preserving foam with viscosity and elasticity suitable for the object to be cooled (type of fresh product).

[0077] However, if the ratio of the foaming agent exceeds the upper limit of 5.00% or the ratio of the shape retainer exceeds the upper limit of 3.00%, the viscosity and elasticity of the freshness-preserving foam will increase, and the foam will tend to become hard overall. Such hard freshness-preserving foam will be difficult to flexibly deform according to the external shape of the fresh product, and will have a reduced effect in absorbing external impacts. For this reason, in the freshness-preserving foam according to the embodiment, the upper limit of the ratio of the foaming agent is set to 5.00% and the upper limit of the ratio of the shape retainer is set to 3.00%, as described above.

[0078] Comparing cooling foam A1 and freshness-preserving foam B1, the difference is that the cooling foam A1 contains 0.00% humectant (see Figure 1), while the freshness-preserving foam B1 contains 0.20% humectant (see Figure 2). As already explained, this is because cooling foam A1 is used in a plastic bag, so it is not necessary to add a humectant. Furthermore, because the proportions of foaming agent and shape-retaining agent contained in cooling foam A1 and freshness-preserving foam B1 are the same, the foam viscosity, elasticity, and diameter are similar.

[0079] Comparing chilled foam A2 and freshness-preserving foam B2, the difference is that chilled foam A2 has a shape-preserving agent content of 1.00% (see Figure 1), while freshness-preserving foam B1 has a shape-preserving agent content of 0.10% (see Figure 2). For chilled foam A2, it is important to maintain the cooling effect for at least three hours while maintaining the foam shape with the shape-preserving agent, whereas for freshness-preserving foam B2, it is important to maintain the foam surrounding the fresh fish for at least three days without collapsing. For this reason, a different shape-preserving agent content is set for freshness-preserving foam B2, taking into account the difference in the intended use of the foam from chilled foam A2.

[0080] As shown in Figure 2, freshness-preserving foam for fresh fish can be produced by setting the foaming agent at approximately 2.00% (e.g., 1.80% to 2.20%) and the shape-retaining agent at approximately 0.10% (e.g., 0.80% to 1.20%). This allows for a relatively long shape-retention period (7 days) and produces a freshness-preserving foam (freshness-preserving foam B2) with approximately six times the flexibility and elasticity of freshness-preserving foam B3 (the sinking weight of freshness-preserving foam B3 is 5 mm, while that of freshness-preserving foam B2 is 29 mm). Covering fresh fish with a sterilizing foam with shape-retaining properties, viscosity, and elasticity like freshness-preserving foam B2 can suppress the growth of bacteria that may develop on the surface of the fresh fish. Furthermore, because freshness-preserving foam B2 has sufficient elasticity, it can function as a buffer and prevent external damage to the fresh fish even when external impacts are applied to the fresh fish.

[0081] The table in Figure 2 shows the bubble diameter of each freshness-preserving foam. As already explained for cooling foam, the larger the bubble diameter, the easier it is to break (disintegrate). On the other hand, the larger the bubble diameter, the easier it is to wash off the foam with water or the like. When used to cover fresh produce with foam, as with freshness-preserving foam, it is preferable that the foam adhering to the fresh produce can be easily washed off. On the other hand, the ease of washing off the foam is also affected by the viscosity of the foam. For example, foam with high viscosity tends to be more difficult to wash off with water than foam with low viscosity. Therefore, when using freshness-preserving foam while taking into account the cleaning burden of the foam, it is desirable to generate freshness-preserving foam by increasing the proportion of foaming agent to increase the bubble diameter, decreasing the proportion of shape-retaining agent to decrease the viscosity of the foam, or adjusting the ratio of shape-retaining agent to foaming agent. By increasing the bubble size or decreasing the viscosity of the foam, the foam becomes easier to wash off with water or the like, making it possible to prevent the freshness-preserving foam from remaining on the fresh produce.

[0082] Taking the above points into consideration, the ratio of foaming agent and shape retaining agent in the freshness-preserving foam is determined, and the freshness-preserving foam is produced. The ratio of foaming agent and shape retaining agent varies depending on the type of fresh product to be used for the freshness-preserving foam. However, comparing freshness-preserving foams B1 to B3 in FIG. 2, freshness-preserving foam B2 has a relatively long shape retention time and sufficient viscosity and elasticity, making it highly versatile for use. Therefore, it is more preferable that the ratio of foaming agent to shape retaining agent be 20:1. Furthermore, as described above, the ratio of foaming agent is preferably around 2.00% (e.g., 1.80% to 2.20%), and the ratio of shape retaining agent is preferably around 0.10% (e.g., 0.08% to 0.12%).

[0083] [Effects of using freshness-preserving foam and cooling foam] By covering fresh produce such as fresh fish with freshness-preserving foam, it is possible to suppress the occurrence and proliferation of bacteria and the like in the fresh produce, thereby delaying spoilage of the fresh produce and making it possible to suppress deterioration of freshness. Furthermore, by using the above-mentioned cooling foam to maintain the temperature of the fresh produce at 0°C or below, deterioration of the fresh produce can be suppressed and freshness can be maintained.

[0084] Furthermore, by making the freshness-preserving foam and cooling foam into a foam shape with a certain degree of viscosity and elasticity, when an external impact is applied to the fresh produce, the freshness-preserving foam and cooling foam can act as a cushioning material to absorb the impact, preventing external damage to the fresh produce (such as scratches or dents).

[0085] Furthermore, by making the freshness-preserving foam and cooling foam foam-shaped, it is possible to reduce the overall weight (weight of the packaging box) compared to when ice water (ice + water) is used as a cooling medium for fresh produce as in the past. By using freshness-preserving foam and cooling foam instead of ice water, it is possible to reduce the overall weight (weight of the packaging box), making it easier to reduce the transportation costs of fresh produce.

[0086] Furthermore, by using both the foam-shaped freshness-preserving foam and the cooling foam, it is possible to more effectively maintain the freshness of fresh produce. For example, in the case of live fish (live fish), the body produces an energy substance for survival called adenosine triphosphate (ATP), thereby maintaining freshness, and furthermore, a surface viscous substance called mucin covers the surface of the fish, thereby preventing the invasion of bacteria from the outside. However, in the case of fish (fresh fish) that has just died, the lack of adenosine triphosphate (ATP) causes rigor mortis to begin, leading to internal decay, and the cessation of mucin secretion may allow bacteria to enter the fresh fish, leading to external decay.

[0087] The cooling foam according to the embodiment can maintain a temperature of 0°C or below for a long period of time, thereby suppressing the temperature rise of fresh fish and thereby suppressing the progression of internal spoilage. Furthermore, the freshness-preserving foam according to the embodiment covers the outside of the fresh fish with the freshness-preserving foam, which prevents bacteria from entering from the outside instead of mucin, thereby suppressing the progression of external spoilage. Therefore, spoilage of fresh products (such as fresh fish) can be suppressed from both internal and external aspects, making it possible to more effectively preserve the freshness of fresh products.

[0088] The cooling foam and freshness-preserving foam according to the present invention have been described above, but the cooling foam and freshness-preserving foam according to the present invention are not limited to those described in the embodiments. For example, the proportions of the foaming agent, shape retainer, and humectant contained in the cooling foam and freshness-preserving foam are not limited to those of the cooling foams A1 to A3 and the freshness-preserving foams B1 to B3 shown in the tables of Figures 1 and 2. These proportions vary depending on the type of perishable product, the intended freshness preservation period, etc., and can be changed or adjusted as appropriate depending on these factors.

[0089] Furthermore, in the embodiment, the case where the freshness-preserving foam contains a moisturizing agent has been described, but the moisturizing agent is not an essential component of the freshness-preserving foam and can be omitted.

[0090] Furthermore, in the embodiment, as explained with reference to the freshness-preserving foam B1 in FIG. 2, if the ratio of foaming agent to shape-retaining agent is low, the freshness-preserving foam may not have a proper foam shape, so it was explained that the ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) is preferably 99.60% or less. However, as mentioned above, it is possible to omit the humectant in the freshness-preserving foam. In this case, it is preferable to increase the amount of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) instead of the humectant, in which case the ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) is 99.80% or less (99.79%). Even if the ratio of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) is 99.80% or less by omitting the humectant, the ratio of foaming agent and shape-retaining agent to the total weight remains unchanged, so the freshness-preserving foam can be properly shaped into a foam.

[0091] Furthermore, even if the humectant is not omitted, as shown in the freshness-preserving foam B1 in Figure 2, if the proportion of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) is 99.59% and the proportion of humectant is 0.20%, the freshness-preserving foam can be properly formed into a foam shape. Therefore, the "liquid for sterilizing fresh produce" according to the present invention can be interpreted as a mixture of electrolyzed hypochlorous water (electrolyzed water, sterilizing water) and a humectant, or as a liquid having a sterilizing effect that is obtained by removing the foaming agent and shape-retaining agent from the entire liquid before the foaming treatment (electrolyzed hypochlorous water (electrolyzed water, sterilizing water) + humectant).

[0092] A1-A3 ... Cooling foam B1-B3 ... Freshness-preserving foam

Claims

1. A cooling foam that is made by adding a foaming agent and a shape-retaining agent to the liquid that serves as the cooling medium for fresh produce, causing it to foam.

2. The cooling foam according to claim 1, characterized in that the liquid accounts for 99.80% or less by weight of the liquid plus the foaming agent and the shape retaining agent.

3. The cooling foam according to claim 2, characterized in that the liquid accounts for 87.00% or more by weight of the liquid plus the foaming agent and the shape retaining agent.

4. The cooling bubble of claim 1, wherein the liquid is water.

5. The cooling foam described in claim 1, characterized in that the shape retaining agent accounts for a weight of 0.01% or more of the total weight of the liquid, the foaming agent and the shape retaining agent.

6. The cooling foam according to claim 5, characterized in that the shape retaining agent accounts for a weight of 3.00% or less of the total weight of the liquid, the foaming agent and the shape retaining agent.

7. The cooling foam according to claim 1, characterized in that the shape-retaining agent is a thickening polysaccharide.

8. The cooling foam according to claim 1, characterized in that the foaming agent accounts for a weight of 0.20% or more of the total weight of the liquid, the foaming agent and the shape retaining agent.

9. The cooling foam according to claim 8, characterized in that the foaming agent accounts for 5.00% or less by weight of the liquid plus the foaming agent and the shape retaining agent.

10. The cooling foam of claim 1, wherein the foaming agent is a non-ionic surfactant.

11. The cooling foam described in claim 1, characterized in that the ratio of the weight of the foaming agent to the weight of the foaming agent and the shape retaining agent added to the liquid is twice the ratio of the weight of the shape retaining agent to the weight of the foaming agent and the shape retaining agent added to the liquid.

12. A freshness-preserving foam that is made by adding a foaming agent and a shape-retaining agent to a liquid used for sterilizing fresh produce and foaming it.

13. The freshness-retaining foam according to claim 12, characterized in that the liquid accounts for 99.80% or less by weight of the liquid plus the foaming agent and the shape-retaining agent.

14. The freshness-retaining foam according to claim 13, characterized in that the liquid accounts for 87.00% or more by weight of the liquid plus the foaming agent and the shape-retaining agent.

15. The freshness-preserving foam according to claim 12, wherein the liquid is electrolyzed water.

16. The freshness-retaining foam according to claim 12, characterized in that the shape retaining agent accounts for a weight of 0.01% or more of the total weight of the liquid, the foaming agent and the shape retaining agent.

17. The freshness-retaining foam according to claim 12, characterized in that the shape retaining agent accounts for a weight of 0.04% or more of the total weight of the liquid, the foaming agent and the shape retaining agent.

18. A freshness-retaining foam as described in claim 16 or 17, characterized in that the shape retaining agent occupies a weight of 3.00% or less of the total weight of the liquid, the foaming agent and the shape retaining agent.

19. The freshness-retaining foam according to claim 12, characterized in that the shape-retaining agent is a thickening polysaccharide.

20. The freshness-retaining foam according to claim 12, characterized in that the foaming agent accounts for a weight of 0.20% or more of the total weight of the liquid plus the foaming agent and the shape retaining agent.

21. The freshness-retaining foam according to claim 20, characterized in that the foaming agent accounts for 5.00% or less by weight of the liquid plus the foaming agent and the shape retaining agent.

22. The freshness-retaining foam of claim 12, wherein the foaming agent is a non-ionic surfactant.

23. A freshness-preserving foam, which is made by adding a foaming agent, a shape-retaining agent and a moisturizing agent to a liquid used for sterilizing fresh produce and foaming it.

24. The freshness-retaining foam of claim 23, wherein the humectant comprises at least one of sorbitol, hyaluronic acid, or sodium hexametaphosphate.

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