JP2023054451A - Method for preserving food material - Google Patents

Abstract

To provide a method for preserving a food material while keeping its flavor and texture as much as possible.SOLUTION: Method for preserving a food material includes a process for placing a food material 1, packed as being inhibited from breezing, in a store 5 with its atmospheric temperature kept at ice temperature and a process for applying the electrostatic field to the food material 1. Properly combining the packing technique for inhibiting the food material 1 from breezing, the preserving technique at ice temperature and the preserving technique for applying the electrostatic field promotes the hibernation state of food material 1 and enables the long-time preservation of food material 1 while keeping the flavor and texture of food material 1 as much as possible.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for preserving foodstuffs, and more particularly to a method for preserving foodstuffs while preserving flavor and texture as much as possible.

In recent years, various methods for preserving foodstuffs have been proposed. For example, Patent Literature 1 below discloses a technique for preserving food by applying a high-voltage electrostatic field to the food below freezing.

JP-A-2006-230257

For example, in chestnut dishes such as chestnut steamed rice, the sweetness and aroma of the chestnut itself as a food ingredient are important. Therefore, it is important to maintain the flavor of fresh chestnuts prior to heat treatment such as pre-boiling in order to maintain the commercial value of fresh chestnuts. If it becomes possible to store fresh chestnuts for a long time while maintaining their flavor, for example, if it becomes possible to adjust the shipping period of fresh chestnuts from late autumn to early spring, the commercial value of fresh chestnuts in the market will be maintained for a relatively long period of time until early spring. It is expected that it will be maintained and return further profits to the production farmers.

In addition to raw chestnuts, if it becomes possible to adjust the peak shipping season while maintaining the flavor and texture of seasonal foodstuffs such as fruits and vegetables, it will be possible to prevent the peak shipping season from overlapping. It is expected that it will be possible to control the decline in distribution prices and stabilize the income of farmers.

According to the technique disclosed in Patent Document 1, foodstuffs can be preserved. However, even with the technique of Patent Document 1, the long-term storage of fresh chestnuts that allows adjustment of the shipping time while maintaining the flavor and texture of fresh chestnuts has not yet been realized. Not only raw chestnuts, as an example, but also to support sustainable production by farmers, it is required to preserve the ingredients for a long time while maintaining the flavor and texture of the ingredients as much as possible. .

An object of the present invention is to provide a method for preserving foodstuffs while preserving their flavor and texture as much as possible.

The present inventors have been intensively studying to solve the above problems, and found that by appropriately combining packaging technology that suppresses respiration of ingredients, storage technology by ice temperature, and storage technology by applying an electrostatic field, It has been found that the hibernation state of foodstuffs is promoted, and it is possible to preserve the foodstuffs for a long period of time while preserving the flavor and texture of the foodstuffs as much as possible.

That is, the present invention for solving the above problems includes, for example, the following aspects.

(Section 1)
A step of placing the foodstuff packaged so as to suppress respiration in a cabinet in which the temperature of the atmosphere is maintained at ice temperature;
applying an electrostatic field to the food material;
How to store ingredients, including
(Section 2)
Item 2. The food storage method according to Item 1, wherein the food is covered with a humidity control material.
(Section 3)
Item 2. A method for preserving foodstuffs according to Item 1, wherein the foodstuffs are packaged together with a humidity conditioning material.
(Section 4)
Item 3. The food storage method according to Item 2, wherein the food is packaged using a heat insulating material.
(Section 5)
Item 4. The method for preserving foodstuffs according to Item 2 or 3, wherein the foodstuffs are MA (Modified Atmosphere) packaged using a bag that adjusts oxygen concentration and carbon dioxide concentration in the packaging.
(Section 6)
Item 6. The food storage method according to any one of Items 1 to 5, wherein the ice temperature is 0°C or lower and the food does not freeze.
(Section 7)
The step of applying an electrostatic field to the food material includes applying a voltage of a predetermined height to a conductive electrode installed in the container, thereby generating the electrostatic field of a predetermined height generated from the conductive electrode. Item 7. The food storage method according to any one of items 1 to 6, wherein the voltage is applied to the food.
(Section 8)
Item 8. A method for preserving raw chestnuts by the method for preserving foodstuffs according to any one of Items 1 to 7.

ADVANTAGE OF THE INVENTION According to this invention, the method of preserving foodstuffs can be provided, maintaining a flavor and texture as much as possible.

FIG. 2 is a diagram schematically showing a state in which foodstuffs are packaged in the method for preserving foodstuffs according to one embodiment of the present invention. 1 is a cross-sectional view showing a schematic configuration of a storage for use in a food storage method according to an embodiment of the present invention; FIG. It is a graph which shows the change of the weight loss rate in a long-term storage test. It is a graph which shows the change of the water|moisture content in a long-term storage test. It is a graph which shows the change of sucrose in a long-term storage test. It is an example of a sheet used for sensory evaluation. It is a graph which shows the change of the fragrance in a long-term storage test. It is a graph which shows the change of food texture in a long-term storage test. It is a graph which shows the change of the sweetness in a long-term storage test. It is a graph which shows the change of acidity in a long-term storage test.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description and drawings, the same reference numerals denote the same or similar components, and redundant description of the same or similar components will be omitted.

In the present invention, a packaging technique for suppressing respiration of foodstuffs, a preservation technique by ice temperature, and a preservation technique by applying an electrostatic field are appropriately combined. As a result, the hibernation state of the food is promoted, and the food can be stored for a long time while maintaining the flavor and texture of the food as much as possible.

In one embodiment of the present invention described below, raw chestnuts will be described as an example of a food material to be preserved.

・Food hibernation The edible part of raw chestnuts is the seed. Fruits and vegetables including fresh chestnuts and fruits and vegetables continue to breathe even after they are harvested. As the raw chestnut grows as a seed, it loses its flavor such as sweetness and aroma, and loses its commercial value. In the present invention, in order to maintain the commercial value of raw chestnuts as a food material for a relatively long period of time, the raw chestnuts are wrapped so as to suppress respiration of the raw chestnuts, and the wrapped raw chestnuts are placed in an atmosphere of ice temperature. It is installed in a storage chamber maintained at a temperature (hereinafter also referred to as a freezing chamber). As a result, it is possible to minimize the respiration of fresh chestnuts, promote the hibernation state of fresh chestnuts, suppress the speed at which fresh chestnuts grow as seeds, and maintain the flavor of fresh chestnuts as much as possible. Raw chestnuts can be stored for a long period of time so that the shipping time can be adjusted.

Fruits and vegetables are the same as raw chestnuts. Fruits and vegetables continue life support activities such as respiration even after harvesting. In the present invention, fruits and vegetables are wrapped so as to suppress respiration of the fruits and vegetables, and the wrapped fruits and vegetables are placed in an ice storage. As a result, it is possible to minimize the respiration of the fruits and vegetables to put them in a hibernation state, and it is possible to preserve the fruits and vegetables for a long period of time while preserving the flavor of the fruits and vegetables as much as possible.

- Packing of foodstuffs In the present invention, foodstuffs are packed so as to suppress respiration of the foodstuffs. As an exemplary means for realizing this, in this embodiment, the foodstuffs are packaged in MA (Modified Atmosphere). MA packaging is a packaging method for changing the atmosphere inside the package to a state suitable for the packaged food. MA packaging of foodstuffs makes it possible to change the atmosphere within the packaging so as to suppress respiration of the foodstuffs. Illustratively, the MA packaging can use a freshness-keeping bag that regulates the oxygen and carbon dioxide concentrations within the bag.

When preserving fruits and vegetables such as fresh chestnuts as foodstuffs to be preserved, if the oxygen concentration is low (for example, about 5 to 10%) and the carbon dioxide concentration is high (for example, about 10 to 15%), , the hibernation state of these ingredients is further promoted. For MA packaging, it is preferable to use a freshness-keeping bag that adjusts the oxygen concentration and carbon dioxide concentration in the bag in this way. Veg Fresh (registered trademark), for example, can be used as the freshness preserving bag.

It should be noted that the means for packaging foodstuffs is not limited to MA packaging. As will be described later in the examples, food can be packaged by combining a heat insulating material such as polystyrene foam with a humidity control sheet described later as long as the food can be prevented from breathing.

- Ice Temperature In the present invention, an electrostatic field is applied to the foodstuffs, and the foodstuffs are preserved by placing them in a storage chamber (ice-sensitive chamber) in which the temperature of the atmosphere is maintained at ice temperature. The ice temperature is a temperature range from 0° C. or lower to just before the food starts to freeze, and can be expressed as a temperature of 0° C. or lower and a temperature at which the food does not freeze. In the present invention, ice temperature is achieved by applying an electrostatic field to the food. Food contains moisture, but by applying an electrostatic field to the food, freezing of the food is prevented even at 0° C. or below, which is the freezing point of water.

- Humidity Conditioning Material In the present invention, the foodstuff can be packaged with or covered with a humidity conditioning material. A humidity control material is a material or material that adjusts the humidity of the atmosphere. By adjusting the relative humidity of the atmosphere within an appropriate range using the humidity control material, the humidity change in the atmosphere due to respiration of fruits and vegetables is suppressed, the speed of growth of fruits and vegetables is suppressed, and the hibernation state of fruits and vegetables is promoted. As the humidity control material, a commercially available humidity control sheet processed into a sheet shape, or the like can be used.

Method for Preserving Food Materials FIG. 1 is a diagram schematically showing a state in which food materials are packaged in a method for preserving food materials according to an embodiment of the present invention.

As shown in FIG. 1(A), in the present embodiment, raw chestnuts 1, which are foodstuffs 1 to be preserved, are covered with a sheet-like humidity conditioning material 3 (humidity conditioning sheet) and placed in a freshness preserving bag 2. Packaged. In the illustrated example, the humidity conditioning material 3 covers one chestnut 1 with one sheet, but the humidity conditioning material 3 may cover a plurality of chestnuts 1 with one sheet. In the embodiment shown in (B), a plurality of raw chestnuts 1 are covered with a sheet-like humidity control material 3 and packaged in a styrofoam box 8 with a lid 8a. The modes shown in (A) and (B) respectively correspond to the packaging modes under the third storage condition and the second storage condition in Examples described later.

The humidity conditioning material 3 may be packaged in the freshness-preserving bag 2 together with the food material 1, or may not be packaged together with the food material 1, depending on the food material to be preserved. The opening of the freshness-keeping bag 2 can be closed with a fastener 4 such as a bag clip or rubber band. When a humidity conditioning sheet processed into a sheet shape is used as the humidity conditioning material 3, the food material 1 may be covered with the humidity conditioning sheet as shown in FIGS. 1(A) and 1(B). The use of the humidity conditioning material 3 can be arbitrarily selected according to the foodstuffs to be preserved.

FIG. 2 is a cross-sectional view showing a schematic configuration of a storage for use in the food storage method according to one embodiment of the present invention.

As shown in Figure 2, the storage chamber 5 provides a closed atmosphere. A metal shelf 6 is installed in the storage 5 while being insulated by an insulator 7 . A freshness-preserving bag 2 for packaging a plurality of ingredients 1 (raw chestnuts 1) is placed on a shelf 6 inside a storage 5. As shown in FIG. A plurality of freshness preserving bags 2 can be placed on the shelf 6. - 特許庁In the drawing, the front side and the back side of the area surrounded by the shelf 6 are open, and the freshness preserving bag 2 is placed on the shelf 6 through the open portion of the shelf 6 . When the foodstuff 1 (fresh chestnuts 1) is packaged in a styrofoam box 8 with a lid 8a, the lidded box 8 is placed on the shelf 6. - 特許庁

A metal shelf 6 is connected to a voltage generator 9, and a voltage of a predetermined level is applied to the shelf 6 through wires 10 and 11. FIG. The metal shelf 6 functions as a conductive electrode, and an electrostatic field with a predetermined height generated from the metal shelf 6 is applied to the foodstuff 1 . That is, in the present embodiment, the step of applying an electrostatic field to the foodstuff 1 is performed by applying a voltage of a predetermined height to the shelf 6 installed in the inside 12 , thereby generating static electricity of a predetermined height from the shelf 6 . It involves applying an electric field to the food material 1 .

A heat insulating material 14 is provided between the inside 12 of the storage 5 and the outer wall 13, and the ice temperature of the inside 12 of the storage 5 is maintained by a cooling device 15. - 特許庁It is desirable that the surface of the heat insulating material 14 facing the inside 12 is insulated.

When the food material 1 is fresh chestnuts 1, for example, the value of the voltage applied by the voltage generator 9 to the shelf 6 is about 3500 volts, and the temperature in the storage chamber 5 maintained by the cooling device 15 is about - 1°C.

As described above, according to the present invention, it is possible to provide a method for preserving food while maintaining flavor and texture as much as possible.

In the present invention, a packaging technique for suppressing respiration of foodstuffs, a preservation technique by ice temperature, and a preservation technique by applying an electrostatic field are appropriately combined. As a result, the hibernation state of the food is promoted, and the food can be stored for a long time while maintaining the flavor and texture of the food as much as possible.

Raw chestnuts, which are exemplified as foodstuffs to be preserved in one embodiment of the present invention, have a large amount of moisture, so that when they are preserved at room temperature, mold immediately develops. For this reason, it is said that the proper storage temperature for raw chestnuts is about -2°C. However, if fresh chestnuts are actually stored at -2°C, they will freeze. Once frozen chestnuts are thawed, the moisture and umami of the chestnuts flow out from the destroyed cell walls, resulting in deterioration of the flavor. This is because when fresh chestnuts are frozen, the volume of water contained in the fresh chestnuts expands and the cell walls of the fresh chestnuts deteriorate.

However, if fresh chestnuts are stored at a temperature of 0°C or higher to prevent deterioration of flavor due to freezing, the eggs of chestnut weevil will hatch. For example, if the use of raw chestnuts such as Japanese confectionery and Western confectionery is limited, it is possible to preserve the chestnuts without causing mold and hatching of chestnut weevil eggs by, for example, pickling the raw chestnuts. . However, for chestnut dishes such as chestnut steamed rice, the sweetness and aroma of chestnuts themselves are important, so sugar-preserved raw chestnuts cannot be used for chestnut dishes.

According to the present invention, fresh chestnuts are preserved without freezing by the preservation technique by ice temperature and the preservation technique by applying an electrostatic field, the deterioration of the chestnut cell wall is suppressed, and the packaging technique that suppresses respiration of fresh chestnuts is used. , the hibernation state of fresh chestnuts is promoted. Thus, according to the present invention, by appropriately combining the packaging technology that suppresses the respiration of raw chestnuts, the storage technology that uses ice temperature, and the storage technology that applies an electrostatic field, flavor and texture are preserved as much as possible. Raw chestnuts can be stored.

Raw chestnuts preserved by the method of the present invention can be shipped from late autumn to early spring. can be provided to Since it is possible to adjust the peak shipping season of raw chestnuts while maintaining the flavor and texture, the income of producing farmers is also stabilized.

In general, most of the harvested raw chestnuts contain eggs of chestnut weevil, and when the eggs hatch, the raw chestnuts are eaten by adults. Such insect damage has long been a problem in the distribution and storage of raw chestnuts, and the eggs of chestnut weevil have been conventionally controlled by fumigation. On the other hand, methyl bromide used in fumigation treatment has been cited as one of the chemical substances that cause ozone depletion, and in recent years its use has been severely restricted from the viewpoint of environmental protection.

According to the present invention, the eggs and larvae of the chestnut weevil are prevented and the raw chestnuts can be preserved for a long period of time by storing the chestnuts in a refrigerator in which the temperature of the atmosphere is maintained at ice temperature.

Although the present invention has been described in terms of specific embodiments, the present invention is not limited to the embodiments described above.

Although raw chestnuts are used as food materials to be preserved in the above-described embodiments, the food materials to be preserved in the present invention are not limited to raw chestnuts. As long as the packaging can suppress respiration and promote the hibernation state, not only raw chestnuts but also fruit, vegetables, and other fruits and vegetables can be used as foodstuffs to be preserved. In addition, foods other than fruits and vegetables can also be preserved as foods as long as the packaging can suppress respiration and promote hibernation. Examples of foodstuffs other than fruits and vegetables whose respiration is suppressed by packaging and whose hibernation state is promoted include, for example, cereals with seeds such as brown rice and barley.

A long-term storage test of raw chestnuts was conducted from October 21, 2020 to June 28, 2021. Raw chestnuts from Kyotanba, Kyoto Prefecture were used for the test. Raw chestnuts used in the long-term storage test were sorted in advance in order to minimize the influence on the results of component analysis and sensory evaluation conducted during the long-term storage test. An individual with a dent on the surface of the demon skin, an individual with a cavity between the demon skin and the seed (edible part), an individual with the surface of the demon skin looking wilted, and an individual with discolored skin. etc. were preliminarily excluded from the preservation test.

The preservation test was conducted by dividing the inside of the ice storage into three test areas, and preparing 11 sets (165 pieces) of fresh chestnuts, each set containing 15 fresh chestnuts, for each test area. The ice-sensing chamber was set to have an internal temperature of −1° C. and an applied voltage of 3500V. Fresh chestnuts were stored under the following three storage conditions in each test section in the ice storage. As the freshness-preserving bag, a commercial freshness-preserving bag manufactured by Holics Co., Ltd. under the product name "Vegefresh Chuck M" (model number: IW-G120L-4) was used. As the humidity control material, a commercially available water absorbent sheet manufactured by Unicharm Corporation under the product name "Freshmaster Freshness-keeping Water Absorbent Sheet" (JAN code: 4903111800162) was used.

- First Storage Condition (Comparative Example 1) Only in the ice storage room Fresh chestnuts were stored as they were placed on the shelf in the ice storage room.
・Second storage condition (Example 1) Ice storage + humidity control sheet + styrofoam A humidity control sheet is laid on the bottom of a box-shaped styrofoam container, and the fresh chestnuts are arranged flat on top of it. The upper part was covered with a humidity control sheet, the opening of the container was covered with foamed polystyrene, and the container was placed on a shelf in an ice storage and stored.
・Third storage condition (Example 2) Ice storage + humidity control sheet + freshness-preserving bag Fresh chestnuts are covered with a humidity-conditioning sheet, and the raw chestnuts covered with the humidity-conditioning sheet are wrapped in a freshness-preserving bag to maintain freshness. The bag was stored by placing it on a shelf in the ice storage.

After starting long-term storage of raw chestnuts under these three types of storage conditions, after 2 weeks, 4 weeks, 8 weeks, . One set of raw chestnuts was taken out from each test plot and subjected to component analysis and sensory evaluation. As criteria for analysis and evaluation, component analysis and sensory evaluation were also performed at the start of long-term storage (week 0).

[Component analysis]
We analyzed the components of fresh chestnuts stored for a long period of time, and confirmed that the components of fresh chestnuts differed depending on the storage conditions. The items to be analyzed were weight, water content, and sucrose. Weights were confirmed on the same 5 individuals in each test plot. For water content and sucrose, 10 individuals were extracted at each analysis timing, and the average values of those individuals were calculated. Moisture analysis was performed using standard test methods for measuring food ingredients.

Analysis of sucrose was performed by the method shown in the following steps.
Step 1) Peel off the demon skin and astringent skin, and homogenize the raw chestnuts with a food processor.
Step 2) Take 2 g of the homogenized fresh chestnuts in a glass tube for analysis, add 30 mL of 80% alcohol solution, and homogenize.
Step 3) Perform ultrasonic treatment in an ultrasonic cleaner for 10 to 30 minutes.
Step 4) Centrifuge the product of step 3 and take out the supernatant.
Step 5) Add 30 mL of alcohol again to the precipitate obtained by centrifugation in Step 4, and repeat Steps 3 and 4 twice.
Step 6) Subject the sucrose standard solution and the collected supernatant to liquid chromatography.
Step 7) Create a calibration curve for the standard solution and calculate the sucrose content.

成分分析の結果について検討する。 The results of component analysis are shown in Tables 1 to 3 and FIGS. 3 to 5.

Consider the results of component analysis.

- Weight In Comparative Example 1, the final weight was about 50%. In Comparative Example 1, the weight had already reached about 64% (decrease rate of about 36%) after 2 months, and the weight decreased at a relatively early stage. On the other hand, in Example 1, the weight becomes about 65% (reduction rate of about 34.5%) after 9 months, and the storage conditions in Example 1 are relative to the weight reduction rate. It was confirmed that there was an effect of extending the storage period by about 7 months compared to the storage conditions in Example 1. Furthermore, in Example 2, the weight was about 96% (reduction rate: about 3.5%) even after 9 months, and the weight at the start of storage was almost maintained.

・Moisture In Comparative Example 1, the moisture content was about 69% (43.27 g / 62.21 g) after 2 months, and about 53% (33.41 g / 62.21 g) after 3 months. As with the weight, the water content decreased at a relatively early stage. In Comparative Example 1, the water content decreased as the storage period extended. As for Comparative Example 1, the analysis of water content after 3 months was final, and the analysis of water content thereafter was stopped. On the other hand, in both Example 1 and Example 2, more than about 94% (58.74 g / 62.21 g) of water was maintained even after 9 months, and the water content at the start of storage was was almost preserved.

In addition, the raw chestnut was cut in half by inserting a kitchen knife into the raw chestnut, and the states of the unripe skin, the astringent skin and the seeds were visually confirmed.

In Comparative Example 1, individuals with cavities were found here and there after 2 weeks. After that, in Comparative Example 1, as the storage period became longer, the number of individuals with cavities and dry astringent skin increased. On the other hand, in both Example 1 and Example 2, the cut surface of the seed was moist even after 9 months, and the moisture was maintained.

・ Sucrose After 2 weeks, the amount of sucrose was about 7 g to about 8 g in all of Comparative Example 1, Example 1 and Example 2, and no difference due to different storage conditions was observed. rice field. However, a difference was observed between the storage conditions in Comparative Example 1 and the storage conditions in Examples 1 and 2 with respect to the amount of sucrose after one month had elapsed.

In Examples 1 and 2, the amount of sucrose after one month passed was about 7 g to about 9 g, and the amount of sucrose analyzed was almost unchanged. On the other hand, in Comparative Example 1, about 11.5 g after 1 month, about 14.9 g after 2 months, about 21.9 g after 3 months, and the amount of sucrose was increased as the storage period increased. As for Comparative Example 1, the analysis of sucrose after 3 months was final, and the subsequent analysis of sucrose was stopped.

Regarding Comparative Example 1, the point that the amount of sucrose increased as the storage period extended was discussed. In Comparative Example 1, the water content decreased with the extension of the storage period, and the amount of sucrose also increased with the extension of the storage period. In Comparative Example 1, many individuals had cavities in the edible portion after 2 months. From these facts, under the storage conditions in Comparative Example 1, the raw chestnuts were ripened without hibernating, and as a result, the amount of sucrose also increased in the raw chestnuts, as in the ripening process in bananas, and the ripening process continued. thought to be in progress.

Based on the above consideration of the results of the component analysis, it is considered inappropriate to ship and distribute the raw chestnuts to the market as products after 3 months (12 weeks) have passed since the storage conditions of Comparative Example 1 were applied. was taken. On the other hand, for the raw chestnuts to which the storage conditions of Example 1 or 2 were applied, the amount of water and the amount of sucrose were generally maintained at the level at the start of storage even after 9 months. confirmed. Especially in Example 2, the decrease in weight was extremely small compared to Example 1, and the weight at the start of storage was almost maintained.

As a result, the raw chestnuts to which the storage conditions of Example 1 or Example 2 are applied can be shipped and distributed to the market as raw chestnuts that retain their flavor and texture until at least 9 months have passed. confirmed to be possible.

[sensory evaluation]
Not only the component analysis but also the sensory evaluation confirmed that the freshness and maturity of raw chestnuts differed depending on the storage conditions. As evaluation items regarding flavor and texture, the evaluation items in the sensory evaluation were aroma (fragrance), texture (moist feeling), taste (strength of sweetness), and sourness (presence or absence of sourness). An example of the sheet used for sensory evaluation is shown in FIG. Using the evaluation sheet shown in FIG. 6, sensory evaluation was performed by the following method.

・Evaluator The evaluator is usually engaged in the preservation, processing, and taste evaluation of raw chestnuts. Five individuals were selected from the study group on the methods.

·Evaluation points Each evaluation item was graded in 7 levels from a minimum of 1 point to a maximum of 7 points, and the average value of the five evaluators was used as the evaluation point.

・Method of presenting samples to be evaluated Note the following points.
・A random 3-digit number was used to identify the sample.
・We chose a plain white container that was just the right size for serving.
・The sample was cooled for 1 hour after heating and then evaluated.
・In order to eliminate differences in evaluation due to climate change, mental change, environmental change, etc., the test was conducted in an environment with constant lighting, temperature and humidity, soundproofing, and ventilation.

・Preparation of sample It was carried out by the method shown in the following steps.
Step 1) Prepare 2 L of water for 15 chestnuts. A 24 cm diameter pan is used with a built-in 200 V IH.
Step 2) Make vertical cuts with a kitchen knife on the flat surface of the chestnut skin.
Step 3) Add fresh chestnuts to the water and bring to a boil over high heat.
Step 4) After boiling, reduce the heat to low and heat for 1 hour.
Step 5) Allow to stand for 1 hour to remove rough heat, and perform sensory evaluation.

官能評価の結果について検討する。 The sensory evaluation results are shown in Tables 4 to 7 and FIGS. 7 to 10.

Consider the results of the sensory evaluation.

・ Fragrance (aroma)
It was felt that in Comparative Example 1, the fragrance was clearly reduced as the storage period was extended. On the other hand, neither Example 1 nor Example 2 showed a decrease in fragrance.

・Texture (moist feeling)
It was felt that in Comparative Example 1, the moist feeling was clearly lowered as the storage period was extended. On the other hand, neither Example 1 nor Example 2 showed a decrease in moist feeling.

・Taste (strength of sweetness)
In all of Comparative Example 1, Example 1 and Example 2, no difference in intensity of sweetness due to different storage conditions was observed.

・Sourness (presence or absence of sourness)
Neither Example 1 nor Example 2 had a sour taste. On the other hand, in Comparative Example 1, the longer the storage period, the stronger the sour taste. After 3 months (12 weeks), the score was 3.4 out of 7 points, but after 5 months (20 weeks), it was 6.5 points, and almost all of the evaluators were critical. I felt a sour taste. Regarding the individual of Comparative Example 1, it was considered that decomposition had progressed after 5 months had passed.

From the above consideration of the results of the sensory evaluation, it is considered inappropriate to ship and distribute the raw chestnuts to the market as a product after 3 months (12 weeks) have passed since the storage conditions of Comparative Example 1 were applied. was taken. On the other hand, for the raw chestnuts to which the storage conditions of Example 1 or Example 2 were applied, the aroma (aroma), texture (moistness), taste (strength of sweetness), It was confirmed that the sourness (presence or absence of sourness) was generally maintained at the level at the start of storage, and that the flavor and texture were maintained as much as possible.

As a result, the raw chestnuts to which the storage conditions of Example 1 or Example 2 are applied can be shipped and distributed to the market as raw chestnuts that retain their flavor and texture until at least 9 months have passed. confirmed to be possible.

1 Ingredients (raw chestnuts)
2 Freshness-keeping bag 3 Humidity control material 4 Fastener 5 Preservation room (ice storage)
6 Metal shelf 7 Insulator 8 Styrofoam box (insulating material box)
9 voltage generators 10, 11 wiring 12 interior 13 outer wall 14 heat insulating material 15 cooling device

Claims (8)

A step of placing the foodstuff packaged so as to suppress respiration in a cabinet in which the temperature of the atmosphere is maintained at ice temperature;
applying an electrostatic field to the food material;
How to store ingredients, including 2. The method of preserving food according to claim 1, wherein the food is covered with a humidity control material. 2. The method of preserving foodstuffs according to claim 1, wherein said foodstuffs are packaged together with a humidity control material. 3. The food storage method according to claim 2, wherein the food is packaged using a heat insulating material. 4. The method of preserving food according to claim 2, wherein the food is MA (Modified Atmosphere) packaged using a bag that adjusts oxygen concentration and carbon dioxide concentration in the package. The method for preserving foodstuffs according to any one of claims 1 to 5, wherein the ice temperature is 0°C or less and a temperature at which the foodstuffs do not freeze. The step of applying an electrostatic field to the food material includes applying a voltage of a predetermined height to a conductive electrode installed in the container, thereby generating the electrostatic field of a predetermined height generated from the conductive electrode. The method for preserving food according to any one of claims 1 to 6, wherein the voltage is applied to the food. A method for preserving raw chestnuts by the method for preserving foodstuffs according to any one of claims 1 to 7.

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