Manufacturing method for frozen bamboo shoots

Abstract

When using ingredients with a high moisture content, there is a problem in that the ingredients stick together, making mechanical filling difficult. Therefore, a method of freezing them individually is used, but temperature changes during transportation or storage can cause the ingredients to stick together. The objective is to provide frozen bamboo shoots that can be sufficiently restored by rehydrating and that can be easily separated without compromising product value even if they stick together during freezing. [Solution] A method for producing frozen bamboo shoots, comprising: a rehydration step of soaking dried bamboo shoots in water; a cooking step of stir-frying the bamboo shoots after the rehydration step with oil and seasonings; and a freezing step of rapidly freezing the cooked bamboo shoots.

Description

Technical Field

[0001] The present invention relates to a method for producing frozen bamboo shoots. More specifically, it relates to a method for producing frozen bamboo shoots that are difficult to block or can be easily loosened even after blocking.

Background Art

[0002] In recent years, with changes in eating habits and lifestyles, various foods are being sold. Among them, frozen foods are popular among consumers because of their ease of cooking, good taste and quality, and their sales are increasing steadily.

[0003] In the case of frozen noodles, there are products of frozen noodles alone and products that combine frozen noodles and ingredients. Among these, products that combine frozen noodles and ingredients are in high demand because they do not require the preparation of ingredients.

[0004] Various methods are known as methods for producing products that combine frozen noodles and ingredients. For example, a method of filling boiled and cooled noodles into a tray, placing pre-frozen ingredients on top, and then freezing, or a method of filling boiled and cooled noodles into a tray, placing non-frozen ingredients on top, and freezing them together are known.

[0005] Here, it is common for the filling of ingredients to be performed by a machine. For dried ingredients or ingredients with a low moisture content, the ingredients do not stick to each other, so they are easy to fill mechanically. However, in the case of ingredients with a high moisture content, there is a problem that the ingredients stick to each other, making it difficult to fill mechanically. Therefore, for ingredients with a high moisture content, a method of freezing them once is taken to prevent the ingredients from sticking to each other (see Patent Document 1).

[0006] When freezing ingredients with a high moisture content, they should be frozen separately. This is because if the ingredients are frozen together, they will have to be thawed again to separate the stuck-together pieces. Furthermore, repeated freezing and thawing causes the ingredients to deteriorate in quality due to freezing denaturation. On the other hand, even if the ingredients are frozen separately, they may stick together due to temperature changes during transport or storage.

[0007] Whether the ingredients stick together due to freezing while stacked or due to temperature changes during transport, attempting to forcibly separate them once they have stuck together will result in damage or loss of the ingredients. Since damaged or lost ingredients lose their commercial value, they have no choice but to be discarded. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-042155

[0009] Menma (bamboo shoots) are used as a topping for frozen noodles. Since menma is a food ingredient that is rehydrated in water after being dried, it has a high water content. Therefore, when filling rehydrated menma as a topping for frozen noodles, it is preferable to freeze them individually beforehand. However, as mentioned above, temperature changes during transportation or storage can cause the menma to stick together. [Overview of the project] [Problems that the invention aims to solve]

[0010] Because bamboo shoots contain fibers, attempting to forcibly separate frozen bamboo shoots that have been bound together will cause them to tear vertically along the fibers, rendering them unsaleable. Furthermore, restoring them with reduced moisture content results in a hard texture unsuitable for consumption.

[0011] This invention was made in view of the above-mentioned problems. Specifically, the objective is to provide menma (bamboo shoots) that can be sufficiently restored by rehydrating and can be easily separated without compromising commercial value even if they have become cohesive during freezing. [Means for solving the problem]

[0012] The inventor diligently investigated whether it was possible to easily separate the clumped bamboo shoots. He then discovered that stir-frying the bamboo shoots in oil just before freezing makes it easy to separate them, thus completing the invention.

[0013] To solve the above problems, the present invention provides a method for producing frozen bamboo shoots, characterized by comprising: a rehydration step of soaking dried bamboo shoots in water; a cooking step of stir-frying the bamboo shoots after the rehydration step with oil and seasonings; and a freezing step of rapidly freezing the cooked bamboo shoots.

[0014] With this method, instead of seasoning by simmering, the bamboo shoots are seasoned by stir-frying, a method not traditionally used, making it easy to separate even bamboo shoots that have become stuck together due to freezing. [Effects of the Invention]

[0015] According to the present invention, the bound pieces of bamboo shoots can be separated without damaging or destroying them. This reduces the decrease in product value and the amount of waste due to damage. In addition, because they can be easily separated, it becomes easier to fill them using machinery. [Modes for carrying out the invention]

[0016] The following describes preferred embodiments for carrying out the present invention. The embodiments described below are merely examples of typical embodiments of the present invention, and this should not be interpreted as narrowing the scope of the invention.

[0017] <<Manufacturing method for frozen bamboo shoots>> The manufacturing method of frozen bamboo shoots according to this embodiment is characterized by comprising a restoration step of rehydrating dried bamboo shoots, a cooking step of frying and seasoning the rehydrated bamboo shoots, and a freezing step of rapidly freezing the cooked bamboo shoots.

[0018] <Restoration step> The method for restoring dried bamboo shoots according to this embodiment is performed by immersing the dried bamboo shoots in a solution multiple times. The solution used for immersion may be at a low temperature or a high temperature. Also, there is no need to keep it still during immersion, and it may be appropriately stirred. Furthermore, except for the first immersion described later, it may be a cooking with heating.

[0019] (First immersion) In this embodiment, in the first immersion, it is desirable to adjust the pH of the solution in which the dried bamboo shoots are immersed to 6 or more.

[0020] As a method for adjusting the solution used for the first immersion, a method of adding an alkaline agent can be mentioned. As the alkaline agent, at least one of sodium hydrogen carbonate, sodium carbonate, trisodium citrate, sodium tripolyphosphate or sodium pyrophosphate or a combination thereof can be used. Among these, it is preferable to use sodium carbonate or sodium hydrogen carbonate.

[0021] As the amount of the solution used for immersion, it is preferable to use a solution with a volume of 10 times or more the weight of the dried food. Also, the temperature of the solution when rehydrating is carried out at normal temperature or low temperature, and hot water or heating is not performed. If accompanied by hot water or heating, the fibers in the food will be hydrolyzed more than necessary, and the texture of the final product will be lost.

[0022] As the immersion time of the first solution, 4 hours or more is preferable, 6 hours or more is more preferable, and 8 hours or more is even more preferable. On the other hand, since there is no difference in effect even if immersed for 24 hours or more, it is preferable to immerse it in a new solution rather than immersing it for 24 hours or more.

[0023] Also, it is preferable to appropriately stir during the immersion. By stirring, the pH concentration difference in the solution can be eliminated, and the variation in the restoration of the dried food can be suppressed.

[0024] Note that it may be immersed only in water without using an alkaline preparation. When immersed only in water, it is necessary to note that it takes more time to restore than immersion with pH adjustment.

[0025] (Second and subsequent immersions) In this embodiment, it should be noted that for the second and subsequent immersions, pH adjustment is not performed using an alkaline preparation as in the first time. Also, the solution used for the second and subsequent immersions is preferably water. As the amount of the solution used for the second and subsequent immersions, it is preferable to use a solution with a volume of 10 times or more the weight of the original dried food. Also, the temperature of the solution when rehydrating is not particularly limited, and hot water may be used or it may be heated. Particularly, by heating and performing rehydration, the time required for rehydration can be shortened.

[0026] As an example of the conditions when boiling, it can be heated to maintain a temperature of 85°C or higher for 120 to 180 minutes.

[0027] The immersion time of the solution for the second and subsequent times is preferably 2 hours or more, more preferably 4 hours or more, and even more preferably 6 hours or more. On the other hand, since there is no difference in the effect even if immersed for 12 hours or more, it is preferable to immerse in a newly replaced solution rather than immersing for 12 hours or more. Also, it is preferable to appropriately stir during the immersion.

[0028] In this embodiment, it is preferable to replace the solution multiple times. However, when flowing the solution over, the solution may not be replaced. When flowing the solution over, it is preferable to immerse for 6 hours or more.

[0029] <Cooking process by heating> In this embodiment, the rehydrated bamboo shoots are stir-fried in oil. One example of the cooking process is to stir-fry the rehydrated bamboo shoots with oil, and then add a seasoning liquid made by mixing sugar, soy sauce, sake, and other seasonings to flavor them. Alternatively, the rehydrated bamboo shoots may be seasoned with a seasoning liquid made by mixing sugar, soy sauce, sake, and other seasonings, and then stir-fried with oil.

[0030] There are no particular restrictions on the type of oil that can be used in the stir-frying process, but vegetable oils are preferred, such as soybean oil, rapeseed oil, corn oil, sesame oil, palm oil, and olive oil. The oils may be used individually, or two or more may be used in combination, taking into consideration the flavor and suitability for production. Furthermore, there are no particular restrictions on the form of the oils, but they are preferably in liquid form.

[0031] <Freezing process> In this embodiment, bamboo shoots that have been stir-fried in oil during the heating process are frozen. The freezing method is not particularly limited and existing methods can be used. Of these, rapid freezing is preferred. Furthermore, when freezing, it is preferable to freeze the bamboo shoots separately from the beginning, or to freeze them while vibrating and stirring. [Examples]

[0032] The present invention will be described in more detail below, but is not limited thereto. Here, dried bamboo shoots will be used as an example.

[0033] (Restoration of bamboo shoots) 50g of dried bamboo shoots (from China) were mixed with 10 times the amount of water. The water temperature was 25°C at this time. Sodium bicarbonate was then added to a concentration of 1.0%. After stirring to dissolve the sodium bicarbonate, the mixture was left to stand for 16 hours (first soaking). Next, the soaking water was discarded, and the bamboo shoots were boiled at 98°C for 2 hours using 30 times the amount of water (first boiling). The water after boiling was discarded, and the bamboo shoots were boiled again at 98°C for 2 hours using 30 times the amount of water (second boiling). Finally, 500g of rehydrated bamboo shoots were obtained.

[0034] (Preparation of the seasoning liquid) A seasoning liquid was prepared by dissolving refined sugar, soy sauce, mirin, monosodium glutamate, etc., in water.

[0035] (Test Example 1) Add 120g of rehydrated bamboo shoots and 0.5g of liquid vegetable oil to a frying pan and stir-fry, being careful not to burn them. After confirming that the oil has coated the bamboo shoots completely, add 18g of seasoning liquid and stir-fry until the liquid is gone.

[0036] (Test Example 2) Except for using 1.0g of vegetable oil, this is the same as in Test Example 1.

[0037] (Test Example 3) Except for using 1.5g of vegetable oil, this is the same as in Test Example 1.

[0038] (Test Example 4) Except for using 2.0g of vegetable oil, this is the same as in Test Example 1.

[0039] (Test Example 5) Add 120g of rehydrated bamboo shoots and 18g of seasoning liquid to a frying pan and stir-fry, being careful not to burn them. After the seasoning liquid has evaporated, add 1.0g of vegetable oil and stir-fry until the oil coats all of the bamboo shoots.

[0040] (Test Example 6) I added 120g of rehydrated bamboo shoots and 18g of seasoning liquid to a frying pan and stir-fried them, being careful not to burn them.

[0041] (Reference example) 120g of rehydrated bamboo shoots and 120g of seasonings were placed in a pot and heated while stirring. After reaching 85°C, the temperature was maintained for 10 minutes. Then, the liquid was drained using a centrifuge until the weight after dehydration (g) / weight before dehydration (g) was 80-90%.

[0042] (Test to confirm ease of unraveling) The bamboo shoots obtained in the above test examples 1-6 and reference example were stacked flat to facilitate blocking. In this state, they were placed in a rapid freezer and rapidly frozen at -18°C. After 24 hours, the blocked bamboo shoots were placed in a plastic bag and loosened by rubbing the bag 10 times from the outside. Then, the bamboo shoots were removed from the bag, and those with two or more pieces stuck together were selected, and the total weight of the stuck pieces (hereinafter referred to as "blocking weight," unit: g) was calculated. The results are shown in Table 1.

[0043] [Table 1]

[0044] As is clear from Table 1, the amount of blocking decreases as the amount of vegetable oil increases (see Test Examples 1-4). Furthermore, even with the same amount of oil, the amount of blocking is reduced when the seasoning is added before stir-frying in oil, rather than stir-frying in oil first and then seasoning (see Test Examples 2 and 5). In contrast, in Test Example 6, where no vegetable oil was used at all, the bamboo shoots remained completely intact. Moreover, in Test Examples 1-5, there were no bamboo shoots that were split along the fibers, whereas in Test Example 6, there were several bamboo shoots that were split lengthwise along the fibers.

[0045] Four panelists compared the taste of test examples 1-6 with the reference example. While the reference example showed even flavor penetration, some variation in flavor penetration was observed in test examples 1-6. However, the variation in flavor penetration was within an acceptable range. On the other hand, in test examples 1-6, the seasoning liquid was heated until all the moisture evaporated, resulting in a mild flavor. Excellent effects were also observed, such as the addition of a savory aroma and the concentration of umami.

[0046] Next, we investigated the effects of using powdered oil and a silicone preparation instead of liquid oil. In Test Example 2, Test Example 7 was the result of using powdered oil instead of liquid vegetable oil, and Test Example 8 was the result of using a silicone preparation. In both cases, the amount added was 1.0 g. The resulting rehydrated bamboo shoots were subjected to the same ease of separation test as described above. The results are shown in Table 2.

[0047] [Table 2]

[0048] As is clear from Table 2, powdered oils and silicone formulations were found to have poor loosening properties. In particular, silicone formulations showed almost no effect.

[0049] As described above, the present invention makes it possible to provide menma that is sufficiently restored by rehydrating and can be easily separated without compromising its commercial value even if it has become cohesive during freezing.

Claims

[Claim 1] A method for manufacturing frozen bamboo shoots, The rehydration process involves soaking the dried bamboo shoots in water, The process involves a heating step where the bamboo shoots, after the restoration process, are stir-fried with oil and seasonings, The freezing process involves rapidly freezing cooked bamboo shoots, A method for producing frozen bamboo shoots, including the method described above.

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