JP7701146B2 - Manufacturing method for refrigerated or frozen vegetables and prepared foods - Google Patents

Description

The present invention relates to a method for producing cooked refrigerated or frozen vegetables and a method for producing prepared dishes using the refrigerated or frozen vegetables obtained by the method.

Conventionally, various cooking methods have been known for imparting a chewy texture to vegetables.
Patent Document 1 describes a method for cooking vegetables, including a step of pouring heated oil evenly over vegetables and a step of frying the oiled vegetables. The document describes that the method produces stir-fried vegetables that have an excellent texture, good color and luster, a small amount of water separation, maintain a sense of volume, and have excellent shelf life.

Patent Document 2 describes how the surfaces of eggplants, radishes, turnips, cucumbers, etc. are heated in a superheated steam atmosphere under reducing conditions with a relatively low oxygen concentration. The document also describes how this treatment inhibits discoloration when the vegetables are subsequently pickled, improves the permeability of salt, vinegar, etc., and when frozen, eliminates the soggy feeling when thawed and improves freezing resistance.

JP 2002-238489 A JP 2019-075999 A

In recent years, the ready-meal market has continued to expand, and a variety of commercially available prepared dishes have been proposed. Among these, there is an ever-increasing demand for delicious and visually appealing prepared dishes. Among the ingredients of prepared dishes, vegetables have a higher water content than meat and other ingredients, and so cooked vegetables are prone to losing their texture when refrigerated or frozen and then heated. In particular, deep-fried and stir-fried vegetables such as agebitashi, chinjaorousu, and hoikoro-ro require a process of frying or frying at high temperatures to achieve a cooked appearance, such as a fried or stir-fried appearance. However, when vegetables that have been frying or frying at high temperatures are refrigerated or frozen, it is difficult to obtain a chewy texture after reheating.

Regarding the above-mentioned problem, Patent Document 1 does not take into consideration obtaining a chewy texture after refrigerating or freezing cooked vegetables and then heating them again, and does not consider any process for achieving this.
Furthermore, as described in Patent Document 2, refrigerated or frozen vegetables obtained through a heat treatment using superheated steam can be reheated to some extent to obtain a chewy texture, but the vegetables do not have an appearance that gives a cooked feel, such as a fried or stir-fried appearance.

The object of the present invention is therefore to provide refrigerated or frozen vegetables that have a good texture and a cooked appearance even after being reheated from a refrigerated or frozen state.

The present invention includes a steam treatment step of heating vegetables with water vapor at 100° C. or higher and 300° C. or lower;
An oil heating step in which the vegetables treated in the steam treatment step are heated by contacting them with oil or fat at 120 ° C. or more and 200 ° C. or less for a heating time of 1 second to 60 seconds or less; and
The present invention provides a method for producing refrigerated or frozen vegetables, which comprises a step of refrigerating or freezing the vegetables treated in an oil heating step.

The present invention also provides a method for producing prepared dishes using refrigerated or frozen vegetables obtained by the above method.

The present invention can provide refrigerated or frozen vegetables that have a good texture even after reheating after refrigeration or freezing, and have a cooked appearance. The present invention can also provide prepared dishes using the refrigerated or frozen vegetables.

The present invention will now be described based on preferred embodiments thereof.
The present invention includes a steam treatment step of heating vegetables with water vapor at 100° C. or higher and 300° C. or lower;
An oil heating step in which the vegetables treated in the steam treatment step are brought into contact with oil or fat at 120 ° C. or more and 200 ° C. or less for a heating time of 1 second to 60 seconds or less; and
The present invention relates to a method for producing refrigerated or frozen vegetables, which comprises a step of refrigerating or freezing the vegetables treated in the oil heating step.
In the following description, the terms "N seconds" and "M minutes" mean "N seconds" and "M minutes," respectively (N and M are numerical values).

The present inventors have intensively studied a method for producing cooked vegetables that have a crisp texture while having a stir-fried or fried appearance when reheated after refrigeration or freezing. In order to produce cooked refrigerated or frozen vegetables, it is necessary to heat them to 85°C for hygienic reasons. On the other hand, the present inventors have found that vegetables that are simply stir-fried or fried in an unheated state and heated to 85°C before being refrigerated or frozen tend to burn or become soft or shriveled when reheated. The present inventors speculate that the above phenomenon is due to overheating, which causes the vegetables to burn, the moisture in the vegetables to evaporate and cause the vegetables to shrivel up, or the pectin in the vegetables to decompose and soften, resulting in a soft texture. They then considered it necessary to avoid overheating in order to obtain a crisp texture while having a fried or fried appearance. Furthermore, as a result of studying various methods that are thought to be capable of heating vegetables while avoiding overheating, they came up with the above-mentioned method of the present invention.

(Steam treatment process)
Examples of vegetables that are the subject of the present invention include leafy vegetables such as cabbage, green onions, Chinese cabbage, spinach, shiso, garland chrysanthemum, lettuce, komatsuna, and bok choy; flower vegetables such as broccoli and cauliflower; underground stem vegetables such as lotus root; sprout vegetables such as bean sprouts; sprout vegetables other than sprouts such as bamboo shoots; stem vegetables, bulb vegetables, and root vegetables such as asparagus, garlic, ginger, and onion; root vegetables such as carrots, turnips, radishes, and burdock; fruit vegetables such as eggplant, tomatoes, bell peppers, chili peppers, pumpkins, and shishito peppers; tubers such as sweet potatoes and potatoes; beans such as soybeans, green peas, and fava beans; mushrooms such as maitake mushrooms, shiitake mushrooms, matsutake mushrooms, enoki mushrooms, bunashimeji mushrooms, king oyster mushrooms, and wood ear mushrooms; and corns such as corn, sweet corn, and baby corn.

Among these, it is preferable to use at least one type selected from leafy vegetables, flower vegetables, sprout vegetables, stem vegetables, bulb vegetables, root and stalk vegetables, root vegetables and fruit vegetables, because they have a high water content and are highly effective when applied to the present invention, and in terms of versatility and improved texture, it is preferable for the vegetable to be one or more types selected from carrots, bell peppers, eggplant, broccoli, cauliflower, asparagus, shishito peppers, pumpkin, cabbage, Chinese cabbage and bean sprouts, and it is particularly preferable for the vegetable to be one or more types selected from carrots, bell peppers, broccoli, asparagus, shishito peppers, pumpkin, cabbage and bean sprouts.

It is preferable that the vegetables to be subjected to the steam treatment step are in an unheated state, since this makes it easier to obtain the chewy texture-related effects of the present invention. However, the vegetables to be subjected to the steam treatment step may be preheated to the extent that the texture-related effects of the present invention can be obtained. An unheated state refers to, for example, vegetables that have not been subjected to a heat treatment at 70°C or higher for 1 second or more, preferably to vegetables that have not been subjected to a heat treatment at 60°C or higher for 1 second or more, and particularly preferably to vegetables that have not been subjected to a heat treatment at 50°C or higher for 1 second or more.

The vegetables used in the present invention are preferably 15g or less per vegetable, since this makes it easier to cook the entire vegetable and more easily obtain a chewy texture while still maintaining a cooked feel. "Per vegetable" here refers to each cut piece if the vegetable is cut. Alternatively, it refers to each torn piece if the vegetable is torn by hand or the like. It also refers to each bean sprout, each shishito pepper, and each bean (hereinafter, when referring to one vegetable, this meaning is used). From these points of view, it is more preferable that each vegetable be 15g or less, and even more preferable that it be 10g or less. The lower limit of the weight of each vegetable is preferably 0.1g or more from the viewpoint of workability, and more preferably 1g or more.

When vegetables are to weigh 15g or less per piece, it is sufficient that at least one of the vegetables subjected to the steam treatment process weighs 15g or less. However, it is preferable that 60% or more of the vegetables subjected to the steam treatment process weigh 15g or less by number, more preferably 80% or more weigh 15g or less, and particularly preferably 90% or more weigh 15g or less.

The size of each vegetable used in the present invention is preferably within 5 cm square, since it is easy to cook the entire vegetable and to obtain a chewy texture while obtaining a cooked appearance. The size of within 5 cm square means that when the vegetable is placed on any horizontal plane and the length, width, and height of its outer shape are measured, the two dimensions other than the smallest dimension among the length, width, and height are each 5 cm or less. For example, if the length, width, and height of a vegetable are measured on a plane and the length is 4 cm, the width is 4 cm, and the height is 3 cm, the vegetable falls within 5 cm square. Note that the length here refers to the maximum length of the shape of the projected view when the vegetable is placed on the plane and projected onto the plane from above, and the width refers to the length in the direction perpendicular to the maximum length. Note that the maximum length refers to the length of the largest line segment that crosses the projected shape. The way in which the vegetables are placed on the plane when measuring is arbitrary, and if it can be confirmed that the two dimensions other than the smallest dimension of the length, width, and height measured in one way are 5 cm or less, even if the two dimensions other than the smallest dimension of the length, width, and height measured in another way are not 5 cm or less, it is considered to be "within 5 cm square". When the length, width, and height of the outer shape of the vegetable are measured on the plane, it is preferable that at least one of the dimensions of the length, width, and height is 1 cm or more, and more preferably 2 cm or more. When the length, width, and height of the outer shape of the vegetable are measured on the plane, it is more preferable that at least two of the dimensions of the length, width, and height are 1 cm or more, and even more preferably 2 cm or more. In particular, it is preferable that the size of each vegetable, especially when cut or torn by hand, is 5 cm square or less.

When the size of each vegetable is within 5 cm square, it is sufficient that at least one of the vegetables subjected to the steam treatment step is within 5 cm square. However, it is preferable that 60% or more of the vegetables are within 5 cm square by number, more preferably 80% or more are within 5 cm square, and particularly preferably 90% or more are within 5 cm square.

The vegetables to be subjected to the steam treatment process may be mixed with other ingredients such as meat or fish. Various ingredients such as seasonings, coating materials, food additives such as antioxidants and pH adjusters, and minerals may also be added to the vegetables in advance. Of the total materials to be subjected to the steam treatment process, the proportion of vegetables is preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

In the steam treatment process, vegetables are heated using steam at 100°C or higher and 300°C or lower. The inventors have found that the steam treatment process in which high-temperature steam at 100°C or higher and 300°C or lower is brought into contact with vegetables makes it easier to maintain the hardness of the surface of the vegetables, obtain a good texture, and also provide a good appearance, even if the vegetables are then refrigerated or frozen after contact with high-temperature oil and then reheated. The reason for this is unclear, but steam heating allows for uniform heating without physical impact, makes it easy to control the heating time, and makes it easy to suppress adverse effects on color tone and yield. In this process, the steam temperature of 100°C or higher has the advantage of being able to heat the vegetables quickly, and the temperature of 300°C or lower has the advantage of not overheating the vegetables. When the steam temperature is higher than 100°C, superheated steam obtained by further heating saturated steam boiled and evaporated at 100°C or higher is used. From the viewpoint of providing a drying effect to the surface of vegetables and improving the cooking effect when heated oil or fat is poured over them, it is more preferable that the temperature of the steam is 140°C or higher. From these viewpoints, the most preferable temperature of the steam is 180°C or higher and 270°C or lower.

The steam treatment step is preferably carried out until the temperature at the center of the vegetables reaches 85°C from the viewpoints of hygiene and obtaining an appropriate texture for the foodstuff. Here, the temperature at the center of the vegetables can be measured by inserting a needle probe thermometer into the center of the vegetable. The center position of the vegetable where the temperature is measured is determined by visual inspection. The center position is determined within the scope of technical common sense in the food industry, and can be, for example, as follows.
For example, in the case of broccoli, which is composed of a stem and a flower bud, the center point of the central axis of the thickest stem in the longitudinal direction is set as the central position. For asparagus stems, the center point of the central axis of the stem in the longitudinal direction is set as the central position. For bean sprouts, which are also cylindrical like asparagus, the center point of the central axis of the cylinder in the longitudinal direction is set as the central position. For cabbage, the center of the thickness direction at the center of the leaf when viewed in a plane is set as the central position. For bell peppers, the center of the thickness direction at the center of the skin surface when viewed in a plane is set as the central position. For shishito peppers, the thermometer is inserted into the central part surrounded by the seeds inside the approximately cylindrical skin to measure. In addition, for carrots, pumpkins, potatoes, sweet potatoes, etc., which are in an indefinite lump shape, the part of the food material that is farthest from any surface is set as the central position. For example, for an object surrounded by a flat cross section and a curved surface, the point that is the largest distance from the closest surface of the object among those surfaces is set as the central position. The core temperature of other vegetables can also be measured in the same manner as above.

The suitable heating time for the steam treatment step may be adjusted as appropriate depending on the type of vegetable and the size of each vegetable. However, for example, a heating time of 10 seconds or more and 10 minutes or less is preferable in terms of the texture and appearance of the resulting vegetables, more preferably 20 seconds or more and 7 minutes or less, and particularly preferably 30 seconds or more and 4 minutes or less. Here, the heating time for the steam treatment step is the time during which the vegetables are in contact with water vapor at 100°C or more and 300°C or less.

In particular, when the vegetables are root vegetables such as carrots, underground stem vegetables such as pumpkin, potatoes, and lotus root, beans, or corn, the heating time in the steam treatment step is preferably from 10 seconds to 10 minutes, more preferably from 20 seconds to 7 minutes, and even more preferably from 30 seconds to 5 minutes.

In addition, when the vegetables are fruit vegetables other than pumpkin, such as bell peppers and shishito peppers, mushrooms, flower vegetables, leafy vegetables such as cabbage, and sprout vegetables such as bean sprouts, the heating time in the steam treatment step is preferably from 10 seconds to 10 minutes, more preferably from 15 seconds to 5 minutes, and even more preferably from 20 seconds to 2 minutes.

When the vegetables are stem vegetables such as asparagus, bulb vegetables, or root and stem vegetables, or bamboo shoots, the heating time in the steam treatment step is preferably from 10 seconds to 10 minutes, more preferably from 20 seconds to 7 minutes, and even more preferably from 30 seconds to 5 minutes.

The amount of steam used in the steam treatment step is preferably 20 kg/hour or more and 300 kg/hour or less, and more preferably 30 kg/hour or more and 200 kg/hour or less, because this makes it easier to obtain vegetables that are chewy and have a good appearance, and because it makes it easier to reduce the moisture content on the surface of the vegetables.

The total amount of steam used in the steam treatment step is preferably within the range of 1 g to 100 g per 1 g of vegetables to be subjected to the steam treatment step, as this makes it easier to obtain vegetables that are firm and have a good appearance, and more preferably within the range of 2 g to 50 g.

There are two types of cooking appliances that use steam at temperatures between 100°C and 300°C: steam injection types that spray steam directly onto ingredients, and steam-filled types that do not spray steam directly onto ingredients but fill the inside of the appliance with steam. Either type may be used.

The vegetables treated by the steam treatment step are subjected to the oil heating step. The manufacturing method of the present invention may have another step between the steam treatment step and the oil heating step. Examples of such another step include a leaving step, a seasoning step, a step of adding food additives, a weight adjustment step, etc. It is preferable that there is no active heating step or active cooling step between the steam treatment step and the oil heating step in terms of ease of temperature control of the vegetables. In particular, it is preferable that the steam treatment step and the oil heating step are performed continuously in terms of ease of temperature control of the vegetables. By performing the steam treatment step and the oil heating step continuously, it is preferable that the time from the end of contact between the water vapor and the vegetables in the steam treatment step to the start of contact between the vegetables and the oil in the oil heating step is within 1 hour, and it is particularly preferable that it is within 20 minutes.

(Oil heating process)
The oil heating step is a step in which the vegetables after the steam treatment step are brought into contact with oils and fats at 120° C. to 200° C. for a heating time of 1 second to 60 seconds. The method of bringing the oils and fats into contact with the vegetables may be a general oil frying method in which the vegetables are fried in heated oils and fats in a pan, or a method in which the heated oils and fats are poured onto the vegetables by pouring them over them. The latter method is preferable in that it is easy to adjust the heating time in a short heating period and also easy to adjust the temperature of the oils and fats.

By setting the temperature of the oil or fat used in the oil heating step to 120°C or higher, it is possible to obtain an appearance with a fried or stir-fried feel, and it is also advantageous in terms of imparting a cooking aroma. By setting the temperature of the oil or fat used in the oil heating step to 200°C or lower, it is possible to avoid deterioration in appearance and texture caused by overheating when refrigerated or frozen vegetables are reheated. From this perspective, it is more preferable that the temperature of the oil or fat used in the oil heating step be 120°C or higher and 270°C or lower, and particularly preferably 150°C or higher and 210°C or lower.

The heating time in the oil heating step is 1 second or more and 60 seconds or less. A heating time of 1 second or more gives an appearance with a stir-fried or fried feel, and a heating time of 60 seconds or less prevents deterioration in appearance and texture caused by overheating when refrigerated or frozen vegetables are reheated. From this perspective, the heating time in the oil heating step is more preferably 2 seconds or more and 50 seconds or less, and particularly preferably 3 seconds or more and 15 seconds or less.

In the oil heating process, the contact between the oil and the vegetables may be continuous or discontinuous. An example of discontinuous contact is when the oil is poured on the vegetables intermittently. The heating time in the oil heating process refers to the contact time with oil at 120°C or higher and 200°C or lower. For example, when oiling is performed continuously, the heating time refers to the time from when the oiling starts and the vegetables start to come into contact with the heated oil until the contact ends. When oiling is performed intermittently, the heating time refers to the total contact time between the vegetables and the heated oil in each oiling, not including the gap time between each oiling.

The total flow rate of the oil or fat used in the oil heating step is preferably 1 g or more and 200 g or less per 1 g of vegetables, as this makes it easier to efficiently obtain a fried or stir-fried texture, and more preferably 2 g or more and 100 g or less.

The oil used in the oil heating step is not particularly limited as long as it is an edible oil, and can be palm oil, palm kernel oil, coconut oil, cocoa butter, shea butter, monkey fat, beef tallow, lard, illipe fat, soybean oil, rapeseed oil, cottonseed oil, safflower oil, sunflower oil, rice oil, corn oil, sesame oil, linseed oil, olive oil, milk fat, etc., or processed oils and fats (hydrogenated oil, fractionated oil, interesterified oil) can be used without any particular limitation. In particular, in the present invention, it is preferable to use a liquid oil at room temperature of 25°C because it is easy to handle in continuous production.

The vegetables after the oil heating step are cooled as necessary and stored by refrigeration or freezing. The vegetables after the oil heating step are preferably refrigerated or frozen without a subsequent heating step, since refrigerated or frozen vegetables having a chewy texture and good appearance when reheated can be easily obtained. The vegetables after the oil heating step are preferably cooled before refrigeration or freezing, from the viewpoints of ease of temperature control and hygiene. Various methods such as air cooling and vacuum cooling can be used for cooling. Refrigeration is usually performed at a temperature higher than 0°C and lower than 15°C, and more preferably 5°C to 10°C. Freezing is usually performed at a temperature higher than -50°C and lower than 0°C, and more preferably -10°C to -45°C.

The refrigerated or frozen vegetables obtained as described above can be used, for example, to produce side dishes. Types of side dishes include simmered dishes, grilled dishes, boiled dishes, steamed dishes, stir-fried dishes, deep-fried dishes, soups, rice bowl dishes, rice dishes other than rice bowl dishes, noodles, salads, etc. In the method for producing side dishes of the present invention, since the refrigerated or frozen vegetables have already been heated, the side dishes can be completed by a simple process of using them as they are for plating or mixing them with other ingredients or seasonings, etc.

Refrigerated or frozen vegetables may be heated either when the prepared dish is produced or when it is eaten. For example, refrigerated or frozen vegetables may be heated when used to produce the prepared dish, and the resulting prepared dish may be heated again when it is eaten. In the present invention, even when heated again, vegetables with a good texture and a good appearance are obtained. In the process of producing prepared dishes, a method suitable for the type of prepared dish to be produced may be appropriately adopted as the method of heating the refrigerated or frozen vegetables. In addition, the method of heating the refrigerated or frozen vegetables or the prepared dish produced using them when it is eaten may be microwave heating, oven heating, or the like, or the refrigerated or frozen vegetables or the food containing them may be fried in a frying pan or the like, or the food may be boiled while sealed in a packaging material, and is not particularly limited.

The present invention will be described below based on examples, but the present invention is not limited to the following examples. In each of the following examples and comparative examples, refrigerated storage was performed at 10°C, and frozen storage was performed at -18°C. Furthermore, rapeseed oil was used as the oil used in the oil heating process. The oil was spread out so that there were no overlapping parts so that the vegetables could easily come into contact with the oil, and the oil was allowed to flow down so that the part where the heated oil flowed down included the entire position of the vegetables when projected from above the flow-down position, and the amount of oil flowing down per area was uniform over the entire part where it flowed down.

[Examples 1-1 to 1-4]
Unheated carrot roots were peeled and chopped into pieces of 5 cm or less square (approximately 3 cm long, approximately 3 cm wide, less than 3 cm high). Each piece weighed approximately 7.0 g. As a steam treatment step, 200 g of the resulting chopped carrots were heated in steam at the temperature shown in Table 1 for the heating time shown in Table 1 using a continuous steam cooker (manufactured by Nakanishi Seisakusho, SV Roaster, steam injection type). The amount of steam was set to 100 kg/hour. It was confirmed that the center temperature of the carrots after steam heating had reached 85°C.
Next, in the oil heating step, oil at the temperature shown in Table 1 was poured from above onto the carrots after the steam treatment step using an oil pouring machine for the heating time shown in Table 1. The total flow rate of oil from the oil pouring machine was 10 g per 1 g of peppers. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling, the carrots were cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 1.

[Comparative Examples 1-1 to 1-2, 1-4 to 1-5]
The same procedures were followed as in Examples 1-1 to 1-4, except that the oil heating step was not performed.

[Comparative Examples 1-3 and 1-6]
The oil heating step was carried out in the same manner as in Example 1-1, except that the steam treatment step was not carried out and the oil pouring time (heating time in the oil heating step) was set to the time shown in Table 1. Other than that, the same procedures were carried out as in Examples 1-1 and 1-3.

(evaluation)
100 g of refrigerated carrots stored in the refrigerator for one day were placed on a plate and heated in a microwave oven at 600 W for 20 seconds. 100 g of frozen carrots stored in the freezer for seven days were placed on a plate and heated in a microwave oven at 600 W for 1 minute 40 seconds. The heated carrots were evaluated according to the following evaluation criteria.

<Evaluation criteria>
●Appearance: Good: Has a cooked feel (fried or stir-fried feel).
△: Little cooked feeling (fried or stir-fried feeling).
×: No cooked feel (fried or stir-fried feel) or burnt.
●Texture: Good and chewy.
△: Not very chewy.
×: Soft or squishy.

As shown in Table 1, in each embodiment that combines a steam treatment step at a specified temperature and time with an oil heating step at a specified temperature and time, it is possible to obtain a cooked appearance and a chewy texture.

[Examples 2-1 to 2-4]
Unheated bell pepper fruits were cut into pieces of 5 cm or less square (approximately 3 cm long, approximately 3 cm wide, and less than approximately 1 cm high). Each piece weighed approximately 2.1 g. In the steam treatment step, 200 g of the resulting cut bell peppers were heated with steam at the temperature shown in Table 2 for the heating time shown in Table 2 using the same cooker as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the central temperature of the bell peppers after steam heating had reached 85°C.
Next, as an oil heating step, oil at the temperature shown in Table 2 was poured from above on the peppers after the steam treatment step using an oil pouring machine for the heating time shown in Table 2. The total flow rate of oil in the oil pouring machine was 34 g per 1 g of peppers. The flow rate of oil in the oil pouring machine was 5 g/( ^cm2 ·sec). The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling was completed, the peppers were cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 2.

[Comparative Examples 2-1 to 2-2, 2-4 to 2-5]
The same procedures were followed as in Examples 2-1 to 2-4, except that the oil heating step was not performed.

[Comparative Examples 2-3 and 2-6]
The oil heating step was carried out in the same manner as in Example 2-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 2. Other than that, the same procedures were carried out as in Examples 2-1 and 2-3.

(evaluation)
100g of the refrigerated peppers stored in the refrigerator for one day were placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of the frozen peppers stored in the freezer for seven days were placed on a plate and heated in a microwave oven at 600W for 1 minute and 40 seconds. The heated peppers were evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 2.

[Examples 3-1 to 3-4]
Unheated broccoli was cut into florets, each of which was within a size of 5 cm square (approximately 3 cm long, approximately 3 cm wide, and less than 3 cm high). Each cut broccoli weighed approximately 4.0 g. In the steam treatment step, 200 g of the resulting cut broccoli was heated in the same cooker as used in Example 1-1 with steam at a temperature shown in Table 3 for a heating time shown in Table 3. The amount of steam was set to 100 kg/hour. It was confirmed that the central temperature of the broccoli after steam heating had reached 85°C.
Next, as an oil heating step, oil at a temperature shown in Table 3 was poured from above onto the broccoli after the steam treatment step using an oil pouring machine for a heating time shown in Table 3. The total flow rate of oil from the oil pouring machine was 18 g per 1 g of broccoli. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling was completed, the broccoli was cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 3.

[Comparative Examples 3-1 to 3-2, 3-4 to 3-5]
The same procedures were followed as in Examples 3-1 to 3-4, except that the oil heating step was not performed.

[Comparative Examples 3-3 and 3-6]
The oil heating step was carried out in the same manner as in Example 3-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 3. Other than that, the same procedures were carried out as in Examples 3-1 and 3-3.

(evaluation)
200 g of refrigerated broccoli stored in the refrigerator for one day was placed on a plate and heated in a microwave oven at 600 W for 20 seconds. 100 g of frozen broccoli stored in the freezer for seven days was placed on a plate and heated in a microwave oven at 600 W for 1 minute and 40 seconds. The heated broccoli was evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 3.

[Examples 4-1 to 4-4]
Unheated asparagus was cut into pieces of approximately 5 cm length. Each cut asparagus piece weighed approximately 3.4 g. As a steam treatment step, 200 g of the obtained cut asparagus was heated with steam at a temperature shown in Table 4 for a heating time shown in Table 4 using the same cooking machine as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the central temperature of the asparagus after steam heating had reached 85°C.
Next, as an oil heating step, oil at the temperature shown in Table 4 was poured from above onto the asparagus after the steam treatment step using an oil pouring machine for the heating time shown in Table 4. The total flow rate of oil from the oil pouring machine was 7 g per 1 g of asparagus. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling was completed, the asparagus was cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 4.

[Comparative Examples 4-1 to 4-2, 4-4 to 4-5]
The same procedures were followed as in Examples 4-1 to 4-4, except that the oil heating step was not performed.

[Comparative Examples 4-3 and 4-6]
The oil heating step was carried out in the same manner as in Example 4-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 4. Other than that, the same procedures were carried out as in Examples 4-1 and 4-3.

(evaluation)
100g of the refrigerated asparagus that had been refrigerated for one day was placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of the frozen asparagus that had been frozen for seven days was placed on a plate and heated in a microwave oven at 600W for 1 minute and 40 seconds. The heated asparagus was evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 4.

[Examples 5-1 to 5-4]
In the steam treatment step, 200 g of unheated shishito peppers (each weighing approximately 4.8 g) were heated with steam at the temperature shown in Table 5 for the heating time shown in Table 5 using the same cooking machine as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the core temperature of the shishito peppers after steam heating had reached 85°C.
Next, as an oil heating step, oil at the temperature shown in Table 5 was poured from above onto the shishito peppers after the steam treatment step using an oil pouring machine for the heating time shown in Table 5. The total flow rate of oil from the oil pouring machine was 5 g per 1 g of shishito peppers. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling, the shishito peppers were cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 5.

[Comparative Examples 5-1 to 5-2, 5-4 to 5-5]
The same procedures were followed as in Examples 5-1 to 5-4, except that the oil heating step was not performed.

[Comparative Examples 5-3 and 5-6]
The oil heating step was carried out in the same manner as in Example 5-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 5. Other than that, the same procedures were carried out as in Examples 5-1 and 5-3.

(evaluation)
100g of the refrigerated shishito peppers stored in the refrigerator for 1 day were placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of the frozen shishito peppers stored in the freezer for 7 days were placed on a plate and heated in a microwave oven at 600W for 1 minute 40 seconds. The heated shishito peppers were evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 5.

[Examples 6-1 to 6-4]
Unheated pumpkin was cut into pieces of 5 cm square or less (approximately 3 cm long, approximately 3 cm wide, less than 3 cm high) (each piece weighing approximately 12.8 g). In the steam treatment step, 200 g of the cut pumpkin was heated with steam at the temperature shown in Table 6 for the heating time shown in Table 6 using the same cooking machine as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the center temperature of the pumpkin after steam heating had reached 85°C.
Next, as an oil heating step, oil at the temperature shown in Table 6 was poured from above onto the pumpkin after the steam treatment step using an oil pouring machine for the heating time shown in Table 6. The total flow rate of oil from the oil pouring machine was 6 g per 1 g of pumpkin. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling, the pumpkin was cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 6.

[Comparative Examples 6-1 to 6-2, 6-4 to 6-5]
The same procedures were followed as in Examples 6-1 to 6-4, except that the oil heating step was not performed.

[Comparative Examples 6-3 and 6-6]
The oil heating step was carried out in the same manner as in Example 6-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 6. Other than that, the same procedures were carried out as in Examples 6-1 and 6-3.

(evaluation)
100g of the refrigerated pumpkin that had been refrigerated for one day was placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of the frozen pumpkin that had been frozen for seven days was placed on a plate and heated in a microwave oven at 600W for 1 minute and 40 seconds. The heated pumpkin was evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 6.

[Examples 7-1 to 7-4]
Unheated cabbage was cut so that each piece weighed about 3.7 g. In the steam treatment step, 200 g of the cut cabbage was heated with steam at the temperature shown in Table 7 for the heating time shown in Table 7 using the same cooking machine as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the central temperature of the cabbage after steam heating had reached 85°C.
Next, as an oil heating step, oil at a temperature shown in Table 7 was poured from above onto the cabbage after the steam treatment step using an oil pouring machine for a heating time shown in Table 7. The total flow rate of oil from the oil pouring machine was 19 g per 1 g of cabbage. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling, the cabbage was cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 7.

[Comparative Examples 7-1 to 7-2, 7-4 to 7-5]
The same procedures were followed as in Examples 7-1 to 7-4, except that the oil heating step was not performed. However, the steam heating time in Comparative Example 7-4 was the time shown in Table 7.

[Comparative Examples 7-3 and 7-6]
The oil heating step was carried out in the same manner as in Example 7-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 7. Other than that, the same procedures were carried out as in Examples 7-1 and 7-3.

(evaluation)
100g of refrigerated cabbage stored in the refrigerator for 1 day was placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of frozen cabbage stored in the freezer for 7 days was placed on a plate and heated in a microwave oven at 600W for 1 minute 40 seconds. The heated cabbage was evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 7.

[Examples 8-1 to 8-4]
In the steam treatment step, 200 g of unheated bean sprouts (each weighing 0.8 g) were heated with steam at the temperature shown in Table 8 for the heating time shown in Table 8 using the same cooker as used in Example 1-1. The amount of steam was set to 100 kg/hour. It was confirmed that the central temperature of the bean sprouts after steam heating had reached 85°C.
Next, as an oil heating step, oil at the temperature shown in Table 8 was poured from above on the bean sprouts after the steam treatment step using an oil pouring machine for the heating time shown in Table 8. The total flow rate of oil in the oil pouring machine was 15 g per 1 g of bean sprouts. The time from the end of steam heating to the start of oil pouring was within 10 minutes. After oiling, the bean sprouts were cooled with cold air at 10°C and then subjected to the preservation treatment shown in Table 8.

[Comparative Examples 8-1 to 8-2, 8-4 to 8-5]
The same procedures were followed as in Examples 8-1 to 8-4, except that the oil heating step was not performed.

[Comparative Examples 8-3 and 8-6]
The oil heating step was carried out in the same manner as in Example 8-1, except that the steam treatment step was not carried out and the oil pouring time was set to the time shown in Table 8. Other than that, the same procedures were carried out as in Examples 8-1 and 8-3.

(evaluation)
100g of refrigerated bean sprouts stored in the refrigerator for 1 day were placed on a plate and heated in a microwave oven at 600W for 20 seconds. 100g of frozen bean sprouts stored in the freezer for 7 days were placed on a plate and heated in a microwave oven at 600W for 1 minute 40 seconds. The heated bean sprouts were evaluated according to the above-mentioned <Evaluation Criteria>. The results are shown in Table 8.

Claims (10)

A steam treatment step of heating at least one vegetable selected from leafy vegetables, flower vegetables, sprout vegetables, stem vegetables, bulb vegetables, root and stem vegetables, root vegetables not including tubers, and fruit vegetables using water vapor at 100°C or more and 300°C or less;
An oil heating step in which the vegetables treated in the steam treatment step are brought into contact with oil or fat at 120 ° C. or more and 200 ° C. or less for a heating time of 3 seconds to 60 seconds; and
A method for producing refrigerated or frozen vegetables, comprising a step of refrigerating or freezing vegetables treated in an oil heating step without heating the vegetables,
In the steam treatment step, steam is used at a rate of 20 kg/hour to 300 kg / hour in a range of 2 g to 50 g per 1 g of vegetables,
In the oil heating step, oil is poured onto the vegetables in an amount of 2 g to 100 g per 1 g of the vegetables,
This method for producing refrigerated or frozen vegetables comprises a step of processing the vegetables in a steam treatment process, the step of processing the vegetables in a steam treatment process, and the step of processing the vegetables in a oil treatment process. The step of processing the vegetables in a steam treatment process and the step of processing the vegetables in a oil treatment process are carried out within 20 minutes. The method for producing refrigerated or frozen vegetables according to claim 1, wherein each vegetable is 5 cm square or less. The method for producing refrigerated or frozen vegetables according to claim 1 or 2, wherein each vegetable weighs 15 g or less. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 3, wherein the vegetables are one or more selected from carrots, bell peppers, broccoli, asparagus, shishito peppers, pumpkin, cabbage and bean sprouts. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 4, wherein the oil heating step is a step of pouring heated oil onto the vegetables to coat them with oil. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 5, wherein water vapor at 140°C or higher and 300°C or lower is used in the steam treatment step. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 6, wherein the heating time in the steam treatment step is 30 seconds or more and 4 minutes or less. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 7, wherein in the steam treatment step, the vegetables are heated until their core temperature reaches 85°C. The method for producing refrigerated or frozen vegetables according to any one of claims 1 to 8, in which the steam treatment step and the oil heating step are carried out consecutively. A method for producing side dishes, comprising producing side dishes using refrigerated or frozen vegetables obtained by the method according to any one of claims 1 to 9.