JP2007159516A - Vegetable preserving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vegetable preserving method for a long period, attaching additional value while retaining or improving palate feeling, nutrient, coloring matter and flavor of vegetables, and capable of preserving vegetables for a long period over a week unit or a month unit. <P>SOLUTION: This vegetable preserving method for preserving vegetables with good freshness for a long period comprises preserving vegetables which pass through a low temperature water washing process, a low temperature steaming process and a preliminary cooling process in order, starting from 0°C to a temperature range until just before the vegetables start to freeze. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for preserving vegetables in which vegetables are preserved with good freshness over a long period (weekly or monthly).

  For example, Patent Literature 1 to Patent Literature 3 have been proposed as a method for preserving vegetables that preserves vegetables with good freshness over a long period of time. Patent Document 1 proposes a storage method in which raw leeks or honey bees are once heated to 50 ° C. to 70 ° C. under a relative humidity condition of 70% or more (Patent Document 1 [Claim 1]). Other). According to this Patent Document 1, it is said that raw leek or raw honey can be well preserved in a state having a crispy texture, taste, color and fragrance similar to fresh raw leek or raw honey by simple processing. .

  Patent Document 2 proposes a freshness maintaining method in which fresh vegetables are immersed in a heated aqueous solution containing a thickener and a bacteriostatic agent (Patent Document 2 [Claim 1] and others). According to this Patent Document 2, fresh vegetables can be kept fresh for about 3 days at room temperature, and fresh vegetables can be used for cut vegetables, lunch boxes, and salads. It can be provided to consumers in a safe state.

  Patent Document 3 discloses a first steam heating step for imparting hardness and functionality and an umami component after heating vegetables cleaned and sterilized with a disinfectant at 30 ° C. to 50 ° C. for 5 to 10 minutes, 55 2nd steam heating process to sterilize by heating at ℃ -80 ℃ for 3-30 minutes, after cooling to 0-30 ℃, ventilate warm water of 20-100 ℃, 2 A drying process for removing 10% to 10% in order is proposed, and a method for producing raw edible vegetables is proposed that is cooled to 0 ° C. to 15 ° C. immediately after the drying process (Patent Document 3 [Claim 1] and others). According to Patent Document 3, various vegetables can be widely used as salad materials, shallow pickles, cooking utensils, or seasoned vegetables.

Japanese Patent Laid-Open No. 2001-231441 JP 2004-215544 JP Japanese Patent Laid-Open No. 2005-151939

  Patent Document 1 points out that dew condensation due to rapid cooling becomes a problem because raw leeks or honey bees are heated and stored under high humidity (Patent Document 1 [0023]). For this reason, cooling after heating is preliminarily cooled at about 10 ° C. to 50 ° C., preferably about 15 ° C. to 30 ° C., and stored at about 1 ° C. to 10 ° C. for final storage. Even if the cooling and storage is appropriate for raw leek or honey bead listed in Patent Document 1, long-term storage in units of weeks or months is not necessary, especially if it is stored at about 1 ° C to 10 ° C without chemical treatment. Is considered difficult. That is, Patent Document 1 proposes short-term storage only for raw leeks or honey bees.

  Although patent document 2 implement | achieves the preservation | save at normal temperature irrespective of the kind of vegetable, the preservation | save period is about 3 days and cannot be regarded as a long-term preservation | save. Further, in this Patent Document 2, since it is a preservation method of immersing vegetables in a heated aqueous solution containing a thickener and a bacteriostatic agent, there is a possibility that the thickener and the bacteriostatic agent remain in the vegetable. It cannot be said that vegetables are preserved as they are. Thus, since patent document 2 can preserve | save a vegetable only for about 3 days, performing chemical processing, it is difficult to come up with the preservation | save method which can preserve | save vegetables for a long term using this patent document 2. FIG.

  Patent Document 3 has a feature of reducing freezing injury during freezing by imparting an umami component to vegetables or strengthening the tissue structure through two steam heating processes (Patent Document [0014] ]). However, vegetables that have undergone such a steam heating process achieve long-term storage for about 1 to 2 months by removing, for example, about 30% of water. Return is required (Patent Documents 3 [0021] and [0023]). From this, it is thought that the vegetables preserved for a long time according to Patent Document 3 may be softened by rehydration, and the vegetables cannot be preserved as they are.

  Although it is considered that Patent Document 3 is most preferable from the viewpoint of keeping vegetables as natural as possible and for a long period of time, there is still room for improvement in that water reconstitution is required for specifications after long-term storage. In other words, while maintaining or improving the texture of vegetables, maintaining or improving nutrients, maintaining or improving pigments, maintaining or improving flavor, still providing added value and being able to store vegetables for a long time in units of weeks or months Is desirable. Therefore, in order to develop a method for long-term preservation of vegetables satisfying the above conditions, studies were made.

  What was developed as a result of the study was a preservation method for preserving vegetables over a long period of time, immediately after the low temperature water washing process, low temperature steaming process and pre-cooling process, the vegetables started to freeze from 0 ° C. It is the preservation method of the vegetable preserve | saved in the temperature range (henceforth a specific temperature range) until. The present invention is a storage method using a so-called “ice temperature (registered trademark)” temperature range for long-term storage of vegetables, but not simply storing vegetables at a specific temperature range, For the purpose of maintaining added value while maintaining or improving feeling, maintaining or improving nutrients, maintaining or improving pigments, maintaining or improving flavor, a low-temperature water washing step, a low-temperature steaming step, and It is characterized in that a precooling step is performed on the vegetables.

  The low temperature water washing step is a step of washing vegetables using a saline solution of 15 ° C. or lower, preferably 10 ° C. to 15 ° C. It is preferable that the salt solution has a salt content of 0.1 wt% to 1.0 wt%. This low-temperature water washing process has a certain sterilization effect by tightening vegetables by using a saline solution of 15 ° C. or lower, and by using a saline solution, in addition to the function of washing away dust attached to the vegetables. Here, if the salt content in the salt solution is less than 0.1 wt%, the sterilizing effect is poor, and conversely if it exceeds 1.0 wt%, the vegetables are undesirably salty. A more preferable ratio of salt content is 0.3 wt% to 0.5 wt%.

  The low temperature steaming step is a step of steaming the vegetables that have undergone the low temperature water washing step with steam at 30 ° C. to 100 ° C., preferably 50 ° C. to 75 ° C., for 1 minute to 60 minutes, preferably 2 minutes to 3 minutes. Here, low temperature steaming means steaming below 100 ° C in a broad sense.In the present invention, it includes 100 ° C, and when the time of the steaming process is sufficiently short, it temporarily exceeds 100 ° C. Shall be included. This low-temperature steamed vegetable eliminates the need for punching during cooking, makes the hard skin and muscles sweet and soft, makes it easier to make pickles in a short time, etc., and shortens the cooking time required for various cooking, etc. Maintaining or improving the texture of vegetables stored for a long period of time, maintaining or improving nutrients, maintaining or improving pigments, maintaining or improving flavor.

  The pre-cooling step is a step of cooling the vegetables that have undergone the low-temperature steaming step with -30 ° C to -50 ° C, preferably around -40 ° C in 1 minute to 30 minutes, preferably 5 minutes to 15 minutes. . This pre-cooling process is a process for cooling the vegetables heated in the low-temperature steam process to a temperature suitable for storage in the subsequent specific temperature zone, in order to leave various properties maintained or improved by the low-temperature steam process. Cool vegetables for 1 to 60 minutes. Here, cold air having a temperature higher than −30 ° C. is not preferable because the cooling time is longer than 60 minutes. Further, if the temperature is lower than −50 ° C., it is not preferable because partial freezing occurs and the vegetable tissue is destroyed.

  Vegetables that have undergone the pre-cooling process may be stored as they are in a specific temperature range (for example, a warehouse), but they will be kept in close contact with each other, and the convenience of taking them out of storage and handling them will be considered. In this case, it is preferable that each vegetable is vacuum-packed and stored at a specific temperature range. Since the vacuum packaged vegetables do not contain air as a heat insulating material between the packaging film and the vegetables, the vegetables can be cooled and stored at a temperature substantially equal to the atmospheric temperature of the space stored in the specific temperature range.

  The vegetable which passed through the preliminary cooling process is preserve | saved in the specific temperature range of 0 degreeC--5 degreeC, Preferably -1 degreeC--3 degreeC. Storage in a specific temperature zone allows for storage of vegetables on a weekly or monthly basis without changing the nature of the vegetables stored at temperatures below 0 ° C. From now on, storage at temperatures exceeding 0 ° C will not result in storage at a specific temperature range. In addition, storage at a temperature lower than −5 ° C. may result in conventionally known frozen storage that exceeds storage at a specific temperature range, and in the vegetables of the present invention that have undergone a low-temperature steaming process, the remaining moisture should be frozen. However, this is not preferable because it may destroy the vegetable structure.

  According to the present invention, regardless of the type of vegetable, for example, maintaining or improving the texture of vegetables, maintaining or improving nutrients, maintaining or improving pigments, maintaining or improving flavor, for example, adding cooking time, etc. It is possible to provide a storage method that can store vegetables for a long period of time in units of weeks or months. And since the preservation | save method of this invention does not perform any chemical treatment except using salt solution at a low-temperature water washing | cleaning process, the preserved vegetables remain natural. As described above, the present invention has an effect of providing a preservation method that can preserve vegetables for a long period of time while giving them added value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing the process from harvesting to shipment of vegetables including the preservation method of the present invention. In this example, from the relationship with the low temperature water washing process, the low temperature steaming process, and the pre-cooling process, the stage for preserving vegetables in a specific temperature range is the "specific temperature storage process", and the stage for vacuum packaging of vegetables is "vacuum if necessary". Called “packaging process”. In the flowchart, a range surrounded by a broken line frame corresponds to the processing procedure of the present invention, and there is a vegetable harvest first and a vegetable stored last.

  Since the harvested vegetables are usually dirty, they are washed with water to remove mud and the like even when the present invention is not followed. In the present invention, as shown in FIG. 1, the vegetables are washed using a saline solution having a salt content of 0.3 wt% to 0.5 wt% at 10 ° C. to 15 ° C. in the low temperature water washing step. Specifically, for example, you may wash the vegetables by storing the salt solution in the washing place provided adjacent to the field of harvest, but if you wash a large amount of vegetables, the proportion of salt will decrease, Since it is difficult to maintain a preferable water temperature, it is advisable to take the harvested vegetables back to a processing plant or the like and wash the vegetables in a washing tank in which salt water whose temperature is controlled is stored. In this case, if a steaming device or the like for performing the subsequent low-temperature steaming process is installed in the processing factory or the like, a series of processes can be performed in order and efficiently. Moreover, since the kind of vegetables may be mixed in the step of the low temperature water washing | cleaning process, it is preferable to use a big washing tank so that as many vegetables as possible can be processed.

  The vegetables that have undergone the low-temperature water washing step are temporarily provisionally stacked and then packed together in a fixed quantity, and then subjected to a low-temperature steaming step for 1 to 60 minutes with steam at 50 ° C to 75 ° C. If the steaming apparatus has a configuration corresponding to continuous processing, the low-temperature steaming process can be performed from the vegetables after the low-temperature water washing process. In this low temperature steaming process, it is sufficient if the vegetables can be steamed at less than 100 ° C. However, the temperature and the processing time vary depending on the kind of vegetables and the same vegetables, depending on the variety, harvest time or harvest place. For this reason, it is preferable to implement this low-temperature steaming process with the same vegetable unit of the same kind harvested at the same place at the same time. In other words, different vegetables and different varieties may be processed simultaneously as long as they can be processed at the same temperature and the same processing time.

  The low temperature steaming process is a variety of cooking for vegetables preserved in accordance with the present invention, such as no need for punching, hard skin and muscles become sweet and soft, and easy to make pickles in a short time. It has the function of maintaining or improving the texture of vegetables stored for a long period of time, maintaining or improving nutrients, maintaining or improving pigments, and maintaining or improving flavor. This is because by steaming vegetables at low temperatures, while suppressing vegetable oxidation, only water-soluble proteins and fats that melt at low temperatures can be extracted, and conversely, proteins and fats that become umami components can be confined in vegetables. It is. From this, the temperature and processing time of a low temperature steaming process are determined so that the effect | action of the said low temperature steaming may fully be exhibited in the vegetable to process.

  The vegetables that have undergone the low-temperature steaming process are cooled with cold air around −40 ° C. for 1 to 60 minutes in the preliminary cooling process for the final specific temperature storage process. This pre-cooling process is intended to cool the vegetables heated in the low-temperature steaming process for the specific temperature preservation process, and to tighten the burnt vegetables. It is preferable to set the conditions so that the cooling time becomes the shortest by adjusting the temperature. Moreover, it is preferable for the said objective that the cooling device used for a preliminary | backup cooling process is provided adjacent to a steaming apparatus, and enables the vegetable which finished the low temperature steaming process to transfer to a preliminary | backup cooling process immediately. From this, it is preferable that the low-temperature steaming process and the preliminary cooling process can be performed in the same processing plant.

  The vegetables after the pre-cooling process are stored in a low temperature warehouse or the like that can maintain the atmospheric temperature in a specific temperature range, and stored in a specific temperature storage process. The refrigerated storage technique used in the specific temperature storage step is suitable for long-term storage of vegetables and the like in a specific temperature range of 0 ° C to -5 ° C, preferably -1 ° C to -3 ° C. It is conceivable to preserve vegetables for a long time using only technology, and in fact, the preservation method of such vegetables is well known. However, the present invention goes through the low-temperature water washing process to the preliminary cooling process, while maintaining or improving the texture of vegetables, maintaining or improving nutrients, maintaining or improving pigments, maintaining or improving flavor, For example, an added value such as shortening the cooking time can be added. Thus, the present invention can be viewed as a technology that adds value to the conventional refrigerated storage technology.

  In the specific temperature storage process, it is sufficient if the vegetables can be stored in a specific temperature range. For example, the vegetables may be stacked in a low temperature warehouse, but for convenience of handling of individual vegetables, the individual vegetables are vacuum packaged by the vacuum packaging process. Good. In this case, relatively large vegetables such as Chinese cabbage, cabbage, lettuce or radish may be vacuum-packed individually. For example, potatoes, sweet potatoes, asparagus, broccoli, cauliflower or onion, etc. Vegetables sold in units may be vacuum packaged in units or weight units to be sold. The vegetables thus vacuum-packed are shipped as many as necessary, and are transported to the shipping destination in a vacuum-packed state. When a refrigerated vehicle that can be loaded at a specific temperature range is used for transporting the vegetables, the preservation method of the present invention is carried out until the vegetables reach the shipping destination. At the shipping destination, the vacuum packaging is opened, and the vegetables are washed once and then used for cooking, for example.

  In accordance with the present invention, long-term storage was attempted for some vegetables. In each of the examples shown below, the low temperature water washing step is a washing place or a water washing tank provided adjacent to the field of harvest source, and the low temperature steaming step is a steaming device installed in a treatment plant ("SelfCooking" manufactured by Rational Japan). Center (registered trademark) 62 ”), the pre-cooling process is a cooling device (QXF-006SF5) manufactured by Fukushima Kogyo Co., Ltd. Each of the vegetables after the pre-cooling step was stored in a low temperature warehouse in which the ambient temperature can be controlled in a temperature range from 0 ° C. to just before the vegetables began to freeze. From the field of harvesting to the processing factory, conventionally known truck transportation is used. The evaluation after storage is a sensory evaluation by tasting of 10 or more people.

Example 1:
1 kg of Komatsuna (leaf stem vegetables) from Okayama Prefecture is harvested, washed with salt solution with a salt content of 0.3 wt% and a water temperature of 15 ° C, transported to a processing plant for 3 minutes with low-temperature steam at a steam temperature of 50 ° C. It is treated in a low temperature steaming process and cooled in a pre-cooling process of about 5 minutes so that the core temperature (the core temperature or the internal temperature of the vegetable; the same shall apply hereinafter) is reduced to 10 ° C or less by cold air of -40 ° C Komatsuna was vacuum-packed in units of 500 g, and then stored in a low-temperature warehouse at a warehouse temperature of −1 ° C. Even after storing for 10 days, this Komatsuna had the same color and flavor as after harvesting, increased umami, and left a crispy texture.

Example 2:
1 kg of spinach (leafy vegetables) from Okayama Prefecture is harvested, washed with salt solution with a salt content of 0.3 wt% and a water temperature of 15 ° C, transported to a processing plant for 3 minutes with low-temperature steam at a steam temperature of 50 ° C. Processed in a low-temperature steaming process, cooled in a pre-cooling process for about 5 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and vacuum-packed spinach in 500g units, then in a low-temperature warehouse Stored at a temperature in the warehouse of -1 ° C. Even after 10 weeks of storage, this spinach had the same color and flavor as after harvesting, increased umami, and left a crispy texture.

Example 3:
After harvesting, 1 kg of Okayama Prefecture's Chingensai (leaf stem vegetables) is washed with a salt solution with a salt content of 0.3 wt% and a water temperature of 15 ° C, transported to a processing plant for 2 minutes with low-temperature steam at a steam temperature of 75 ° C. Processed in a low-temperature steaming process, cooled in a pre-cooling process for about 5 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and vacuum-packed Chingensai in units of 500g, then in a low-temperature warehouse Stored at a temperature in the warehouse of -1 ° C. Even after storage for 10 weeks, this Chinggensai had the same color and flavor as after harvesting, increased umami, and left a crispy texture.

Example 4 and Example 5:
10 kg of potatoes from Okayama Prefecture (“Makein”, root vegetables) after harvesting, 0.5 wt% salt, 15 ° C. saline (compared to Examples 1 to 3) As a normal treatment (Example 4) in which it is first stored at the post-harvest hardness as much as possible, it is recommended to use a low-temperature steam with a steam temperature of 80 ° C for 20 minutes. Processed in the teaming process, cooled in a precooling process of about 15 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and after vacuum packaging of potatoes in units of 3 kg, in the warehouse at a low temperature warehouse Stored at a temperature of -1 ° C. In addition, as a special treatment (Example 5) that preserves in a softer state after harvesting, it is treated in a low-temperature steaming process for 20 minutes with low-temperature steam at a steam temperature of 90 ° C to 100 ° C, and the core temperature is reduced by cold air at -40 ° C. After cooling in a pre-cooling step of about 15 minutes so that the temperature was 10 ° C. or less, potato was vacuum-packed in units of 3 kg, and stored in a low temperature warehouse at a warehouse temperature of −1 ° C. Each of the normal and specially treated potatoes had the same color and flavor as after harvesting even after storage for 6 months, and the umami increased. Moreover, the potato of the normal processing did not lose its shape even when cooked. On the contrary, the potato of the special processing could be easily crushed for potato salad or the like.

Example 6:
5kg of sweet potatoes from Tokushima Prefecture ("Naruto Kintoki", root vegetables) are harvested, washed with 0.5 wt% salt water and 15 ° C salt water, transported to a processing plant, and steam temperature 90 ° C to 100 ° C Processed in a low temperature steaming process for 20 minutes with low temperature steam, cooled in a precooling process for about 15 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and vacuum-packed sweet potatoes in units of 3 kg Then, it was stored in a low temperature warehouse at a warehouse temperature of -1 ° C. Even after storage for 6 months, the sweet potato had the same color and flavor as after harvesting, and the umami and sweetness were increased.

Example 7:
After harvesting, 5 kg of carrots (root vegetables) from Aomori Prefecture are washed with a salt solution of 0.5 wt% salt and water temperature of 15 ° C and transported to a treatment plant for 30 minutes with low-temperature steam at a steam temperature of 90 ° C to 100 ° C. In the low-temperature steaming process, cool in the pre-cooling process for about 15 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and after vacuum packaging carrots in units of 1kg, And stored in the warehouse at a temperature of -1 ° C. Even after storing for 6 months, the carrot had the same color and flavor as after harvesting, and the umami and sweetness increased.

Example 8:
10 kg of onion (flower stalk vegetables) from Hyogo Prefecture after harvesting, salt solution of 0.5 wt% salt water at a temperature of 15 ° C (onion is a flower stalk vegetable, but since the leaves are dense, the same as root vegetables Was used, and was taken to a treatment plant and treated with low-temperature steam at a steam temperature of 90 ° C to 100 ° C in a low-temperature steaming process for 15 minutes. After cooling in a pre-cooling step of about 15 minutes so that the core temperature becomes 10 ° C. or less by cold air, the onion was vacuum-packed in units of 3 kg, and then stored at a warehouse temperature of −1 ° C. in a low temperature warehouse. Even after storing this onion for 50 days, it had the same color and flavor as after harvesting, and the umami increased.

Example 9:
5 kg of burdock (root vegetables) from Ibaraki Prefecture is harvested, washed with 0.5 wt% salt water and 15 ° C salt water, transported to a treatment plant, and steamed at a low temperature of 90 ° C to 100 ° C for 20 minutes. In the low temperature steaming process, the core is cooled down to about 10 ° C by cooling at a temperature of -40 ° C, and the burdock is vacuum-packed in units of 1kg, and then stored in a low-temperature warehouse. And stored in the warehouse at a temperature of -1 ° C. Even after storing the burdock for 6 months, the burdock had the same color and flavor as after harvesting, and the umami increased.

Example 10:
After harvesting 5 kg of lotus root (vegetables) from Okayama Prefecture, it is washed with 0.5 wt% salt water and 15 ° C salt water, transported to a treatment plant, and steamed at a low temperature of 50 ° C for 20 minutes. Processed in the teaming process, cooled in a pre-cooling process of about 15 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and after vacuum packaging of lotus roots in units of 1 kg, in the warehouse at a low temperature warehouse Stored at a temperature of -1 ° C. Even after storing for 6 months, the lotus root had the same color and flavor as after harvesting, and the umami increased.

Example 11:
After harvesting, 10 kg of taro (root vegetables) from Ehime Prefecture is washed with saline solution with a salt content of 0.5 wt% and a water temperature of 15 ° C. Processed in the teaming process, cooled in a pre-cooling process of about 15 minutes so that the core temperature becomes 10 ° C or less with cold air of -40 ° C, vacuum packaged taro in units of 1 kg, then in the warehouse at a low temperature warehouse Stored at -40 ° C. Even after storing this taro for 6 months, it had the same hue and flavor as after harvesting, and its umami increased.

Example 12:
After harvesting 5 kg of broccoli (flower stalk vegetables) from Nagano Prefecture, it is washed with a salt solution with a salt content of 0.3 wt% and a water temperature of 15 ° C, transported to a processing plant, and cooled for 5 minutes with low-temperature steam at a steam temperature of 75 ° C. Processed in the steaming process, cooled in a precooling process of about 15 minutes so that the core temperature becomes 10 ° C or less with cold air of -40 ° C, vacuum-packed broccoli in a single unit, and then in a low temperature warehouse Stored at a temperature in the warehouse of -1 ° C. Even after the broccoli was stored for 6 months, it had the same hue and flavor as after harvesting, and the umami increased.

Example 13:
1 kg of asparagus (flower stalk vegetables) from Okayama Prefecture is harvested, washed with salt solution with a salt content of 0.3 wt% and a water temperature of 15 ° C, transported to a processing plant, and cooled for 3 minutes with low-temperature steam at a steam temperature of 50 ° C. Processed in the steaming process, cooled in a pre-cooling process for about 15 minutes so that the core temperature is 10 ° C or less with cold air of -40 ° C, vacuum packed asparagus in units of 100 g, and then stored in a low temperature warehouse It was stored at an internal temperature of -1 ° C. Even after 2 weeks of storage, this asparagus had the same hue and flavor as after harvesting, and the umami increased.

Example 14:
1kg of green peas (beans) produced in Fukushima prefecture is harvested, washed with 0.3wt% salt water and 15 ° C salt water, transported to a processing plant, and steamed at a low temperature of 70 ° C for 3 minutes. Processed in a process, cooled in a pre-cooling process of about 15 minutes so that the core temperature becomes 10 ° C or less with cold air of -40 ° C, vacuum packed the green peas in units of 500g, then the temperature in the warehouse in a low temperature warehouse Stored at -1 ° C. Even after storing the green peas for 2 months, the green peas had the same hue and flavor as after harvesting, and the taste was increased.

Example 15:
10kg of corn ("Sweet corn", cereal) produced in Nagano Prefecture is harvested, washed with salt solution with a salt content of 0.3wt% and a water temperature of 15 ° C, transported to a processing plant, and a low steam temperature of 90 ° C to 100 ° C Treated with steam for a low temperature steaming process for 20 minutes, cooled at a temperature of -40 ° C in a precooling step for about 15 minutes so that the core temperature is 10 ° C or lower, and vacuum-packed sweet corn in single units Then, it was stored in a low temperature warehouse at a warehouse temperature of -1 ° C. Even after storing this corn for 6 months, it had the same color and flavor as after harvesting, and its umami increased.

Example 16:
After harvesting 5 kg of pumpkin ("Bochan Nanjing", fruit and vegetables) from Okayama Prefecture, wash with salt water with a salt content of 0.3 wt% and a water temperature of 15 ° C, and transport to a processing plant where the steam temperature is between 90 ° C and 100 ° C. Processed in a low temperature steaming process for 20 minutes with low temperature steam, cooled in a pre-cooling process for about 15 minutes so that the core temperature becomes 10 ° C or less with cold air at -40 ° C, and vacuum-packed pumpkins in single units Then, it was stored in a low temperature warehouse at a warehouse temperature of -1 ° C. Even after storing this pumpkin for 6 months, it had the same color and flavor as after harvesting, and its umami increased.

It is a flowchart showing from harvesting to shipment of vegetables including the preservation method of the present invention.

Claims (7)

A preservation method for preserving vegetables with good freshness over a long period of time, wherein vegetables that have been subjected to a low-temperature water washing process, a low-temperature steaming process, and a pre-cooling process in order are stored in a temperature range from 0 ° C. to just before the vegetables begin to freeze. How to save. The method for preserving vegetables according to claim 1, wherein the low-temperature water washing step comprises washing the vegetables using a saline solution of 15 ° C or lower. The method for preserving vegetables according to claim 2, wherein the salt solution has a salt content of 0.1 wt% to 1.0 wt%. The method for preserving vegetables according to claim 1, wherein the low-temperature steaming step steams the vegetables that have undergone the low-temperature water washing step with steam at 30 ° C to 100 ° C for 1 to 60 minutes. The method for preserving vegetables according to claim 1, wherein the preliminary cooling step cools the vegetables that have undergone the low-temperature steaming step with cold air of -30 ° C to -50 ° C for 1 minute to 30 minutes. The method for preserving vegetables according to claim 1, wherein the vegetables that have undergone the pre-cooling step are vacuum-packed and stored in a temperature range from 0 ° C to just before the vegetables begin to freeze. The vegetable preservation method of Claim 1 which preserve | saves the vegetable which passed through the precooling process in the temperature range of 0 degreeC--5 degreeC.

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