JPH09275896A - Preservation and packaging of food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the simple and easy preservation of vegetables and fruits, etc., in high quality, minimization of the amount of a packaging material used and reduction in disposal cost according to a specific packaging method. SOLUTION: The whole surface of a food is initially coated with an aqueous solution containing alginic acid and a water-soluble compound such as pullulan and the resultant film is then brought into contact with an aqueous solution of a polyvalent metallic salt, e.g. calcium chloride to insolubilize the alginic acid and provide a coating film. The resultant food coated with the coating film is subsequently brought into contact with water to dissolve the water-soluble compound in the water. Thereby, the gas permeability of the coating film is regulated to package the food. The alginic acid is converted into an aqueous solution containing the alginic acid dissolved in an acid or an alkali, e.g. an aqueous solution of sodium alginate and the concentration thereof is regulated to 0.5-6wt.% for use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of storing and packaging foods such as fruits and vegetables and processed foods in a high quality state. In particular, in the present specification, "food" is to be broadly construed to include agricultural products such as fruits and vegetables and processed foods.

[0002]

2. Description of the Related Art Even after being harvested, fruits and vegetables breathe, evaporate water, and have other chemical and physiological life functions. Vegetables and fruits break down sugar and organic acids and breathe,
Acquires chemical energy to sustain life activities. When the respiratory action becomes active, sugar and organic acids are consumed and the taste deteriorates. Therefore, it is necessary to suppress the respiratory action in order to store and package in high quality. In addition, the plant
It matures while releasing ethylene, a gas hormone. Ethylene released from plants accelerates plant ripening.
Therefore, it is important to control the ethylene amount to the optimum value.

In consideration of the above, a packaging method has been developed in which food is packaged in a plastic film and preserved in high quality. According to this method, the gas permeability of the plastic film used is adjusted to preserve food in high quality. Techniques for achieving this are described in, for example, the following gazettes. JP-A-6-165636 JP-A-6-209701 JP-A-6-248100 JP-A-7-000101 JP-A-7-000100 JP-A-7-102081

[0004] Japanese Patent Laid-Open Publication No. 1993-242242 describes a film in which a non-porous resin layer is laminated on a perforated film or a polymethylpentene film to adjust the gas permeability of oxygen, carbon dioxide, etc. of the entire film. It Describes a method of MA-packing fruits and vegetables by adjusting the gas permeability of the film to be packed. The publication describes a method of selecting the gas permeability of the film to be packed to the optimum value,
Further, the publication describes a method of using a mixture of EEA, 4MIP and an unsaturated carboxylic acid modified polyolefin to optimize oxygen and carbon dioxide gas concentrations in a packaging atmosphere.

[0005]

The method for storing and packaging foods described in these publications optimizes the storage environment by packaging the food with a plastic film. This method adjusts the gas permeability of the plastic film to the optimum value,
Food can be stored and packaged in high quality. However, the method of packaging food using such a plastic film cannot optimize the storage environment unless the plastic film is completely sealed to package the food. For example, an unsealed plastic film does not allow the gas to permeate the plastic film and is vented into the freely packaged interior.

Further, the packaging method using a plastic film has a drawback that it is difficult to dispose of it after use. The plastic film is incinerated and discarded,
Since the amount of heat generated is large, the incinerator is damaged and the incineration cost is increased. Further, since the amount of use thereof increases, the incineration cost increases.

Furthermore, in the method of packaging a plastic film in a hermetically sealed structure, it sometimes takes time to bring the plastic film into close contact with the surface of the food. For example, in the method of storing food by forming a plastic film into a bag, it takes time to exhaust the air in the bag after the food is put therein. Moreover, even if nitrogen gas or the like is enclosed in the bag, it takes time and effort.

[0008] The present invention has been developed for the purpose of solving such disadvantages. An important object of the present invention is to easily and easily preserve food of high quality,
It is an object of the present invention to provide a food storage and packaging method that can minimize the amount of packaging material used and reduce disposal costs. Further, another important object of the present invention is to provide a method for storing and packaging foods, which can adjust the gas permeability to an optimum value by a simple method to optimize the storage environment of the foods and preserve them in high quality. It is in.

[0009]

According to a first aspect of the present invention, there is provided a method for preserving and packaging foods, wherein the entire surface of the food is coated with an aqueous solution containing alginic acid, and then alginic acid is a polyvalent metal such as calcium salt. It is characterized in that it is brought into contact with an aqueous solution of salt to be insolubilized to form a coating film, and the food is coated with the insolubilized alginic acid coating film and stored.

As the aqueous solution containing alginic acid, an aqueous solution in which alginic acid is dissolved in an acid or an alkali, or an aqueous solution in which alginate such as sodium alginate, potassium alginate or ammonium alginate is dissolved in water can be used.

As the aqueous solution of polyvalent metal salt, an aqueous solution of metal salt such as calcium chloride, barium chloride, aluminum sulfate, zinc sulfate, copper sulfate, strontium chloride can be used.

According to a second aspect of the present invention, there is provided a method for preserving and packaging food, wherein the entire surface of the food is coated with an aqueous solution containing alginic acid and a water-soluble compound, and a film containing alginic acid and a water-soluble compound is coated with a calcium salt or the like. Contact with an aqueous solution of a polyvalent metal salt to insolubilize alginic acid to form a coating film, and then contact the food coated with the coating film with water to dissolve the water-soluble compound in water and adjust the gas permeability of the coating film. It is characterized by

Water-soluble compounds added to sodium alginate include natural polysaccharides such as pullulan and starch, sucrose, glucose, oligosaccharides (cyclodextrins), polyvinyl alcohol, monovalent salts which do not gel sodium alginate, for example, , Sodium chloride and potassium chloride can be used.

Further, in the method for storing and packaging food according to claim 3 of the present invention, the entire surface of the food is coated with an aqueous solution containing alginic acid, and the film containing alginic acid is an aqueous solution of a polyvalent metal salt such as calcium salt. It is characterized in that alginic acid is insolubilized by contacting with to form a coating film, and the surface of the coating film is further coated with a coating film containing an antifungal agent.

As the antifungal agent, for example, thiabendazole, o-phenylphenol, sodium o-phenylphenol, diphenyl, preservatives in the Food Sanitation Law, oil additives such as food additives and spices having antibacterial properties can be used.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a method for storing and packaging foods for embodying the technical idea of the present invention, and the present invention does not specify the method for storing and packaging the followings.

The food storage and packaging method of the present invention comprises coating the whole surface of a food with an aqueous solution containing alginic acid and coagulating the alginic acid with a polyvalent metal salt such as calcium salt to insolubilize the food. Cover with. The thickness of the coating film can be adjusted by the concentration of the aqueous solution containing alginic acid. The viscosity of an aqueous solution of alginic acid increases as the concentration of alginic acid increases. When an aqueous solution containing highly viscous alginic acid is used, the film thickness attached to the surface of food becomes thick. For example, an aqueous solution of sodium alginate has a higher viscosity as the concentration increases, so that a food can be dipped in a highly concentrated aqueous solution of sodium alginate and the surface thereof can be coated with a thick aqueous solution of sodium alginate. Further, also in the method of spraying an aqueous solution of sodium alginate and coating it on the surface of food, the concentration of the aqueous solution containing alginic acid can be increased to increase the viscosity and increase the film thickness. The film thickness for coating food with an aqueous solution containing alginic acid is adjusted to an optimum value depending on the type of food. For foods for which a coating film having low gas permeability, in other words, a gas-permeable coating film, is suitable, the concentration of the aqueous solution of alginic acid is reduced to reduce the film thickness. Although the concentration of the aqueous solution containing alginic acid is not constant depending on the type of alginic acid and the type of food, for example,
Sodium alginate has a concentration of 0.5 wt% to 6 wt
%, Preferably 1 to 5 wt%.

Furthermore, the method for storing and packaging food according to the present invention is
A water-soluble compound is added to the aqueous solution of alginic acid to adjust the gas permeability of the coating film. When the amount of the water-soluble compound added is increased, the gas permeability of the coating film is reduced, and in other words, a coating film through which gas easily passes can be formed. Alginic acid coagulates,
This is because the water-soluble compound does not coagulate, so that the water-soluble compound can be removed by washing with water in the coagulated state of alginic acid, and fine pores that allow gas to permeate can be provided in the part of the water-soluble compound.

1 to 3 show a state in which the gas permeability of the coating film decreases as the amount of the water-soluble compound added to alginic acid increases. 1 is a coating film in which 25 parts by weight of pullulan, which is a water-soluble compound, is added to 75 parts by weight of sodium alginate, and FIG. 2 is a coating film in which 50 parts by weight of pullulan is added to 50 parts by weight of sodium alginate, FIG. 3 shows the gas permeability of a coating film having 75 parts by weight of pullulan added to 25 parts by weight of sodium alginate. In these figures, the horizontal axis represents the concentration of the added additive of sodium alginate and pullulan, which is a water-soluble compound. Gas permeability was measured according to JIS P8117 at 20 ° C. and 65%. For the gas permeability test, a B-type Gurley type densometer manufactured by Toyo Seiki Seisakusho Co., Ltd. was used.

As shown in FIGS. 1 to 3, the gas permeability of the coating film decreases as the amount of pullulan which is a natural polysaccharide added as a water-soluble compound increases. Furthermore, the higher the concentrations of sodium alginate and pullulan, the higher the gas permeability of the coating film. Further, in these figures, □ indicates the gas permeability of the coating film not washed with water, and ○ indicates the gas permeability of the coating film washed with water.
When the coating film to which pullulan, which is a water-soluble compound, is added is washed with water, the gas permeability decreases, as indicated by the circles, and the gas easily permeates.

However, the graphs shown in FIGS. 1 to 3 show the gas permeability of the coating film produced as described below. Aqueous solution containing alginic acid and pullulan 5c per side
m is applied to one side of a corrugated cardboard liner to form a film of an aqueous solution containing alginic acid and pullulan, and a film thickness of 500 μm, on the surface of the corrugated cardboard liner. A 5 wt% calcium chloride aqueous solution is sprayed on the aqueous solution of alginic acid and pullulan applied to the surface of the corrugated board liner to solidify the alginic acid. Then, the alginic acid coagulated film is washed with water to dissolve the water-soluble compound and adjust the gas permeability. The gas permeability of the coating film, which is solidified on the surface of the corrugated board liner and whose gas permeability is adjusted, is measured. However, the gas permeability is measured in a state where the coating film is laminated on a corrugated cardboard liner having a gas permeability of 70 seconds. When the gas permeability of the coating film thus manufactured was measured, it was as shown in FIGS.

The gas permeability of the coating film varies depending on the type of polyvalent metal salt that solidifies the aqueous solution containing alginic acid. For example, when an aqueous solution containing 1 wt% of sodium alginate and 1 wt% of pullulan was coagulated with the following polyvalent metal salts of ,, the gas permeability of the coating film was as follows. However, the concentration of the polyvalent metal salt was 5 wt%, and the coating film was the same as the film of which gas permeability was measured as shown in FIGS.

Copper sulfate: 270 seconds strontium chloride: 290 seconds Barium chloride: 240 seconds Aluminum sulfate: 130 seconds

Furthermore, the gas permeability of the coating film also changes depending on the type of water-soluble compound added to alginic acid. For example, in the water-soluble compound added to 1 wt% sodium alginate,
The coating film prepared by dipping an aqueous solution containing alginic acid and a water-soluble compound in a 5 wt% calcium chloride aqueous solution to coagulate alginic acid is
The gas permeability was as follows. However, the amount of the water-soluble compound added was 1 wt%, and the method for producing the coating film was the same as that for the coating film shown in FIGS.

Starch: 280 seconds Sucrose: 110 seconds Cyclodextrin: 230 seconds Sodium chloride: 90 seconds

From the above, according to the method for preserving and packaging foods of the present invention, the amount and kind of the water-soluble compound added to the aqueous solution containing alginic acid and the kind of the polyvalent metal salt are adjusted to prepare the coating film. The gas permeability can be adjusted to the optimum value for food.

[0027]

【Example】

[Example 1] In the following steps, Sudachi is packaged and stored so that the color does not change. A 2 wt% sodium alginate aqueous solution is applied to the entire surface of Sudachi. The simplest method of applying an aqueous solution of sodium alginate to Sudachi is to soak Sudachi in an aqueous solution of sodium alginate. However, the surface of Sudachi can be sprayed with an aqueous solution of sodium alginate to be applied. Sudachi coated with sodium alginate aqueous solution,
Immerse in a 5 wt% calcium chloride aqueous solution to solidify sodium alginate for 3 minutes. Sodium alginate is coated with an insolubilized coating film in which a part of sodium is replaced with calcium to solidify. Sudachi is taken out of the calcium chloride aqueous solution, washed with water, and the coating film on the surface is dried.

When the Sudachi whose surface was coated with the coating film as described above was stored at a temperature of 25 ° C. and a humidity of 60% for 5 days, the results shown in Table 1 were obtained.

[0029]

[Table 1]

As is apparent from this table, in the Sudachi of Example 1 whose surface is covered with the coating film, the green color did not change even after 5 days, and no mold was generated. On the other hand, in the case of the untreated Sudachi whose surface was not covered with the coating film, 37 were discolored to yellow after 5 days, and 5 were moldy on the surface.

Example 2 A mandarin orange surface was prepared in the same manner as in Example 1 except that mandarin orange was used instead of Sudachi, and the concentration of the sodium alginate aqueous solution in which the mandarin orange was dipped was changed from 2 wt% to 1 wt%. Cover with a coating film. Further, the mandarin orange is dipped in a 1% sodium alginate aqueous solution containing 10 ppm of a fungicide (thiabendazole). Then, add 3 to a 5 wt% calcium chloride solution.
Soak for a minute to solidify the sodium alginate containing the fungicide. It is taken out of the aqueous calcium chloride solution, washed with water and then dried. The mandarin orange thus treated is entirely covered with a double-layered coating film.

The 30 oranges treated as described above had no mold on their surface even after being stored at a temperature of 25 ° C. and a humidity of 60% for 30 days. With regard to the mandarin oranges whose surface was not covered with the coating film, four of the 30 mandarin oranges had mold on the surface in the same environment.

Example 3 Sudachi was dipped in the same manner as in Example 1 except that the concentration of the aqueous sodium alginate solution in which Sudachi was dipped was changed from 2 wt% to 1 wt%, and 1 wt% of pullulan was added as a water-soluble compound. The surface of is coated with a coating film. Sudachi treated by this method is entirely covered with a coating film having a gas permeability adjusted with a water-soluble compound.

As described above, the Sudachi whose entire surface was coated with the coating film was heated at a temperature of 25 ° C. and a humidity of 60.
When stored for 5 days, the results are shown in Table 2.

[0035]

[Table 2]

As is apparent from this table, in the Sudachi of Example 3 whose surface is coated with the coating film, the green color did not change even after 5 days, and no mold was generated.

[Example 4] A mandarin orange surface was coated with a coating film in the same manner as in Example 2 except that 1 wt% of pullulan was added as a water-soluble compound in addition to 1 wt% of an aqueous sodium alginate solution in which mandarin orange was dipped. To do. The mandarin orange coated by this method is entirely coated with a coating film whose gas permeability is adjusted with a water-soluble compound.

The mandarin orange whose entire surface was coated with the coating film as described above had a temperature of 25 ° C. and a humidity of 60.
Even after storing at 30% for 30 days, no mold was generated on the surface.

[Example 5] The entire surface of the banana is covered with a coating film in the same manner as in Example 3 except that the food is changed from oranges to bananas. The banana treated by this method is entirely coated with a coating film having a gas permeability adjusted with a water-soluble compound. Thus, the banana having the entire surface coated with the coating film was stored at a temperature of 25 ° C. and a humidity of 60% for 5 days, and the black-brown area was extremely small as compared with the conventional storage method. Bananas whose surface was not covered with a coating film were stored under the same conditions, and the black-brown area was 14.7%.
The banana coated in this example had the black-brown area reduced to only 1.4% of the total surface. That is, the banana treated by the method of the present invention was slower in the appearance of black brown spots than the untreated one, and the ripeness could be controlled.

[Example 6] The entire surface of the rice cake is coated with a coating film in the same manner as in Example 3 except that the food is changed from mandarin orange to rice cake. The rice cake treated by this method is entirely coated with a coating film whose gas permeability is adjusted with a water-soluble compound. In this way, the rice cake coated on the entire surface with the coating film and the non-treated rice cake which had not been treated were inoculated with the rice cake derived from the rice cake, and the culture test was conducted. The culture test was performed at a temperature of 20 ° C and a humidity of 60%.
I went the day. As a result, the rice cake coated in Example 6 was suppressed in the growth of mold as compared with the untreated rice cake, and an excellent preservation effect was observed.

[0041]

The food preservation and packaging method of the present invention has a feature that food can be preserved and packaged in high quality simply and easily. This is because the storage and packaging method of the present invention applies sodium alginate to the entire surface of the food and solidifies the film of sodium alginate with calcium or magnesium to form an insoluble coating film. In particular, the storage and packaging method of the present invention has a feature that a film of sodium alginate is directly formed on the surface of the food and the film is solidified to form a coating film, so that the entire surface of the food can be covered in a sealed state.

Further, since the entire surface of the food is covered with the thin coating film, the total amount of the coating film used for packaging can be extremely reduced, which is incomparable with the conventional plastic film. Also, the coating film obtained by solidifying sodium alginate has a calorific value of about 1/4 that of the plastic film.
Therefore, even if this is incinerated and discarded, the heat generated does not damage the incinerator. This is synergistic with the extremely small amount used, and has the advantage of significantly reducing disposal costs.

Furthermore, since the coating film obtained by solidifying sodium alginate can be eaten as it is, it is possible to eat food without removing the coating film. Therefore, unlike a plastic film, there is no need to peel and remove the coating film, and there is a feature that handling is easy.

Due to the above-mentioned features, the method of preserving and packaging food according to the present invention can simplify the packaging of processed foods and the like, leading to reduction of waste from packaging materials in distribution and sales, and extension of shelf life. There is a feature that leads to. This method is a completely new packaging form that can handle waste such as foods, which will be a big problem in the future. Further, in transporting special agricultural products, it becomes possible to maintain freshness, and it is possible to exert effects such as long-distance transport, quality preservation, superiority in storage, and expansion of transport range.

The method of using a plastic film for packaging processed foods has the advantage that the plastic does not rot or decompose, but causes the problem of waste disposal. Regarding the issue of the global environment, restrictions on the use of plastic packaging materials containers have begun overseas. In Japan as well, the implementation of the Packaging Recycling Law requires that packaging materials be reduced, containers be recycled, or be easily incinerated. In these respects, the method for preserving and packaging food according to the present invention is an eco-friendly material, which leads to a reduction in recycling costs associated with a reduction in the amount of packaging materials and realizes extremely excellent features.

Furthermore, in the method for preserving and packaging food according to claim 2 of the present invention, the water permeability of the coating film can be adjusted by adding the water solubility compound to sodium alginate and removing the water solubility compound in the water washing step. . Therefore, there is a feature that various foods can be stored and packaged in a high quality condition in an optimum environment by an extremely simple method.

Further, according to the storage and packaging method of claim 3 of the present invention, since the antifungal agent is added for packaging, the generation of microorganisms such as mold is minimized and the food is packaged in a high quality state. There is also a feature that can be done.

[Brief description of drawings]

FIG. 1 is a graph showing the gas permeability with respect to the concentrations of sodium alginate and a water-soluble compound.

FIG. 2 is a graph showing gas air permeability with respect to concentrations of sodium alginate and a water-soluble compound.

FIG. 3 is a graph showing gas air permeability with respect to concentrations of sodium alginate and a water-soluble compound.

Claims (4)

[Claims] 1. The entire surface of a food is coated with an aqueous solution containing alginic acid, and then the alginic acid is brought into contact with an aqueous solution of a polyvalent metal salt such as a calcium salt to insolubilize it to form a coating film. The insolubilized coating film forms the food. A method for preserving and packaging foods, which comprises coating and storing. 2. The entire surface of the food is coated with an aqueous solution containing alginic acid and a water-soluble compound, and the coating film containing alginic acid and a water-soluble compound is contacted with an aqueous solution of a polyvalent metal salt such as calcium salt to insolubilize the alginic acid. A method for preserving and packaging foods, wherein the food coated with the coating film is brought into contact with water to dissolve the water-soluble compound in water to adjust the gas permeability of the coating film. 3. The entire surface of the food is coated with an aqueous solution containing alginic acid, and the coating film containing alginic acid is brought into contact with an aqueous solution of a polyvalent metal salt such as calcium to insolubilize alginic acid to form a coating film. A method for preserving and packaging foods, characterized in that the surface of the film is coated with a coating film containing an antifungal agent. 4. The method for preserving and packaging foods according to claim 1, wherein the polyvalent metal salt is calcium chloride.