JPH0412688B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for producing frozen matsutake mushrooms, and more particularly, to a method for producing frozen matsutake mushrooms that enables long-term storage without impairing the inherent flavor of matsutake mushrooms. ``Prior art and its problems'' Matsutake mushrooms have been highly valued for a long time, and it is said that ``a hundred blades of pine mushrooms cost one sho of rice,'' which is said to be ``no match for a man's taste.'' Since then, it has been considered a food that is far from common people. In modern times, the demand for matsutake mushrooms is increasing while the production volume is decreasing dramatically, and there is a desire in many fields including the food industry to provide matsutake mushrooms at a lower price. No suitable solution has been found. The reasons for the high price of matsutake mushrooms include the high temperature and humidity during the harvesting period, which causes the harvested matsutake mushrooms to rot before they can be shipped, the decline in matsutake mountains due to natural destruction, and matsutake fields. A drastic decrease in the absolute amount of ``shiro'' is considered. The drastic decrease in “shiro” is due to
Mountain management is said to be the cause, but due to changes in lifestyle, farmers no longer go to Matsutake mountains to make firewood, the fallen leaf layer becomes thicker, the humidity in the forest area increases, and it becomes an environment where microorganisms can easily breed. The Trichoderma fungus, which is thought to also harm the matsutake fungus, grows deep in the soil of Shiro and obstructs the growth of the matsutake fungus. Matsutake mushrooms are commonly referred to as ``typhoon mushrooms,'' and they are shipped to the market all at once during the typhoon season, but because they cannot be stored properly, they often dry out or rot. For this reason, many people have tried to preserve matsutake mushrooms by freezing them in order to preserve them more stably, but with the conventional method, the flavor of matsutake mushrooms is completely lost after thawing. It had become completely impractical. "Object of the Invention" Therefore, an object of the present invention is to provide a novel method for producing frozen matsutake mushrooms. Another object of the present invention is to provide a method for producing frozen matsutake mushrooms that solves the problems after thawing in freezing matsutake mushrooms, produces frozen matsutake mushrooms with better restorability, and enables long-term storage of matsutake mushrooms. shall be. A further object of the present invention is to provide a method for producing frozen matsutake mushrooms that enables long-term storage of matsutake mushrooms, provides a stable supply of matsutake mushrooms, and reduces prices. "Structure of the Invention" The method for producing frozen matsutake of the present invention involves placing matsutake under static conditions at low temperature and low humidity with relative humidity adjusted to 50% or less for a certain period of time to reduce its moisture content. It is characterized by rapid freezing. The moisture content of matsutake mushrooms is generally 85 to 88.3%, and other foods can be frozen with this level of moisture content, even when subjected to general quick freezing, with the flavor of the food sufficiently preserved. However, in the case of matsutake mushrooms, simply rapidly freezing them in this way will not cause drips or
The aroma, texture, etc. were all gone. As a result of intensive research, the present inventor came to the conclusion that the cause of this is the significant tissue destruction of matsutake mushrooms caused by ice crystals generated during freezing, and furthermore, as shown in Table 1, the water content of each part of matsutake mushrooms We found that there were differences in the rates. Therefore, simply quick-freezing matsutake mushrooms would be the same as freezing different substances under the same freezing conditions, and the problems described above would occur because optimal freezing conditions could not be achieved for each part. It has been found that tissue destruction during such rapid freezing becomes significant, especially in areas with a high moisture content, which impairs the flavor after thawing. Based on this knowledge, the present inventor further conducted intensive research and found that, as mentioned above, if a portion of the moisture is removed from matsutake mushrooms before rapid freezing, they can withstand long-term storage. The inventors have discovered that it is possible to obtain a high-quality product that does not lose the inherent flavor of matsutake mushrooms even after thawing, and have developed the present invention. The present invention will be explained in more detail below. The matsutake mushrooms used in the method for producing frozen matsutake mushrooms of the present invention are not particularly limited, but preferably those that meet the conditions shown below are desirable. In other words, in the growth stages of matsutake, medium-sized,
In other words, those with buds or semi-open buds, especially those in the bud state, are desirable, and the caps are thick and shiny, clear and elastic, the stems are thick and elastic, and the diameter of the stems is approximately the same as the diameter of the cap. It is about
In addition, the flesh should be silvery white without any browning spots caused by pests or other causes, and it should also have a strong aroma. Its size is 10 to 30 mm in diameter, more preferably 15 to 20 mm, length 50 to 120 mm, more preferably 80 to 100 mm, and weight 30 to 130 g, more preferably 50 to 90 g. It is preferable that the degree of Medium-sized matsutake mushrooms are preferable because matsutake mushrooms that are small during the growth stage, that is, in the strawberry or solid state, may become spongy or have dry pots after thawing. In addition, large-sized plants that are open during the growth stage will have a good fragrance after thawing, but there is a risk that the folds may turn brown or wrinkles may form on the hat. This is because the thawing condition is inferior to that of . In the present invention, matsutake mushrooms are placed under static conditions at low temperature and low humidity with relative humidity adjusted to 50% or less for a certain period of time to reduce their moisture content, and then quickly frozen. The process of removing moisture by leaving it under static conditions at low temperature and low humidity for a certain period of time reduces the moisture content of the matsutake mushroom without destroying its tissue, and also makes the moisture content of each part as equal as possible. This is to reduce tissue damage to matsutake mushrooms caused by ice crystals that occur during rapid freezing. In other words, if matsutake mushrooms are kept under the appropriate conditions shown below and some of their water is removed, a large amount of water will evaporate from the cap and folds of the matsutake mushroom, while less water will evaporate from the stem. It was found that the moisture content of the parts became uniform. When the moisture content of each part of the matsutake mushroom becomes equal in this way, it is possible to select the optimal quick freezing conditions for that moisture content, and it is possible to quickly freeze each part of the matsutake mushroom, which would occur if the moisture content of each part of the matsutake mushroom was different. This is because problems arising from inappropriate conditions will be resolved. To remove some of the moisture from matsutake mushrooms, for example, the temperature is +1 to +
The matsutake mushrooms are grown at 5° C. in an air-conditioned atmosphere with low humidity, preferably 30-50% relative humidity, e.g. in an air-conditioned apparatus by circulating conditioned air, for a period of time, e.g. 3-12 hours. , more preferably by storing for 5 to 7 hours. The reason why some of the moisture in matsutake mushrooms is removed under these conditions is because matsutake mushrooms are a food that is extremely susceptible to deterioration. This is because the tissues of the matsutake mushrooms are destroyed, the freshness of the matsutake mushrooms is greatly reduced, and there is a risk that they may turn brown. Matsutake mushrooms are kept under the above-mentioned water removal conditions to remove a portion of their water, and an appropriate overall water removal rate is about 10 to 25%. In other words, if the water removal rate is less than 10%,
There is not much difference in quality deterioration after thawing compared to when rapid freezing is performed without removing some of the water, but on the other hand, when the water removal rate exceeds 25%, the flavor of matsutake mushrooms deteriorates due to water removal. This is because there is a risk of
Furthermore, if the water removal rate of the matsutake mushroom is maintained as a whole within the above range, the water content of each part of the matsutake mushroom can be made uniform. In the method for producing frozen matsutake mushrooms of the present invention, frozen matsutake mushrooms are obtained by removing part of the moisture from the matsutake mushrooms as described above and then rapidly freezing them. As a quick freezing method, various methods known as general food freezing techniques can be used, such as air blast method, brine method, etc., but preferably CPF method etc. Rapid freezing at -70 to -90℃ for 10 to 15 minutes. The frozen matsutake mushrooms obtained in this way are stored at -20 to -35°C, preferably -25 to -30°C until used, and after thawing, preferably natural thawing,
Matsutake mushrooms are cooked and used in various dishes, but not only during long-term frozen storage (for example, 6 months to 1 year), but also for a long time after thawing, for example, 0 to 3 days, the quality of matsutake mushrooms is destroyed due to tissue destruction. There is no progress in deterioration of the flavor, and the flavor is comparable to that of fresh matsutake mushrooms. "Examples" The present invention will be explained in more detail based on Examples below. Example 1 After harvesting matsutake mushrooms at various growth stages, the temperature was increased by +1°C.
The matsutake mushrooms were placed in a drying device air-conditioned at ~+5° C. and a relative humidity of 30 to 50%, and kept in the drying device for 7 hours while circulating conditioned air to remove about 20% of the moisture from the matsutake mushrooms. After a predetermined period of time had elapsed, the matsutake mushrooms were taken out of the apparatus and immediately rapidly frozen at -90°C for 20 minutes according to a conventional method to obtain frozen matsutake mushrooms. The frozen matsutake mushrooms were stored in a freezer set at -20°C for about one year. After that, the frozen matsutake mushrooms were taken out from the freezer, allowed to thaw naturally, and then stored at 5°C for the specified period shown in Table 2. This was then cooked as grilled matsutake mushrooms, which were sampled by a panel of 45 chefs to determine their freshness. The quality was evaluated in six categories: color, hardness, odor, taste, and syneresis.
The average results are shown in Table 2. Comparative Example 1 For comparison, raw matsutake mushrooms at various growth stages were harvested and stored at 5°C for the specified period shown in Table 2.
Grilled matsutake mushrooms were cooked, and the quality was evaluated by a panelist in the same manner as in Example 1. The results are shown in Table 2. Comparative Example 2 For comparison, matsutake mushrooms at various growth stages were immediately frozen at -5° C. for 30 minutes in a conventional manner immediately after harvesting to obtain frozen matsutake mushrooms. The frozen matsutake mushrooms were stored in a freezer set at -20°C for about 1 year, then taken out and allowed to thaw naturally, and further stored at 5°C for the specified period shown in Table 2, then roasted and cooked as matsutake mushrooms.
Similar to Example 1, quality evaluation was performed by a panel. The results are shown in Table 2. Example 2 After thawing, matsutake mushrooms were prepared in the same manner as in Example 1, except that approximately 25% of the moisture in the matsutake mushrooms was removed by holding them in an air-conditioned drying device at a temperature of +1 to +5°C and a humidity of 40% for 5 hours. After a predetermined period of time had elapsed, quality evaluation was conducted by a panel. The results are shown in Table 3. Example 3 The matsutake mushrooms were thawed in the same manner as in Example 1, except that about 10% of the moisture in the matsutake mushrooms was removed by holding them in an air-conditioned drying device at a temperature of +1 to +5°C and a humidity of 40% for 2 hours. Quality evaluation after the passage of time was conducted by a panel. The results are shown in Table 3. Each of the above examples shows that the preservation method of the present invention is clearly superior to the conventional frozen preservation method of Comparative Example 2. In other words, in a simple numerical evaluation, in the case of raw matsutake mushrooms, the numbers of the present invention are inferior to Comparative Example 1, but compared to Comparative Example 2 of the conventional simple freezing preservation method, the numbers of the present invention are inferior. Definitely excellent. Example 3 with the worst number among the examples
In Example 2, it is sufficiently edible on the second day after thawing, and in Example 2, it is sufficiently edible on the fourth day as well. Furthermore, in Example 1, the product can be eaten for up to 6 days. These facts show how difficult and impossible frozen preservation of matsutake mushrooms has been in the past, and that the frozen preservation method of the present invention is clearly superior to conventional methods. The fact that frozen matsutake mushrooms can be eaten for up to six days after thawing is revolutionary compared to fresh matsutake mushrooms. "Effects of the Invention" As described above, the present invention allows matsutake mushrooms to be grown at a relative humidity of 50%.
This is a method for producing frozen matsutake mushrooms, in which they are placed under static conditions at low temperature and low humidity adjusted to below % for a certain period of time to reduce their moisture content, and then are quickly frozen.
It is possible to provide frozen matsutake mushrooms that can withstand long-term storage and retain the same quality as fresh matsutake mushrooms even after thawing, enabling stable storage and supply of matsutake mushrooms, and helping to reduce the price of matsutake mushrooms. This will make a major contribution.

【table】

【table】

[Table] *Evaluation of freshness, color, hardness, odor, taste, and syneresis was performed according to the following criteria.
〓3 Very good 〓2 Good 0 Slightly bad 〓1
Bad 〓3 Very bad / Not acceptable

【table】

Claims (1)

[Claims] 1. Matsutake mushrooms are placed under low temperature, low humidity static conditions with relative humidity adjusted to 50% or less for a certain period of time or more to reduce their moisture content, and then rapidly frozen. Method for producing frozen matsutake mushrooms. 2 In claim 1, 10 to 10 matsutake mushrooms
A method for producing frozen matsutake mushrooms, which involves removing 25% by weight of water and then quickly freezing. 3 In claim 1 or 2, the decrease in the moisture content of matsutake mushrooms is caused by humidity +1 to +5°C,
3~ in conditioned air with relative humidity of 30~50%
A method for producing frozen matsutake mushrooms by keeping them for 12 hours. 4. The method for producing frozen matsutake mushrooms according to any one of claims 1 to 3, wherein the quick freezing is carried out at a temperature of -70 to -90°C.