JP2009165446A - Method for freeze-drying cortinellus shiitake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for freeze-drying Cortinellus shiitake, which has no problems such as scattering of mushroom spore, colloidization of mushroom cellular tissue, variation of tissue by shrinkage, deformation of Cortinellus shiitake, heat damage etc., during drying, maintains the original form of raw Cortinellus shiitake to the fullest extent, is quickly restored to an original state in water during cooking and is excellently user friendly, especially a drying method for enhancing flavor and fragrance as well as nutrient of Cortinellus shiitake in the process of drying. <P>SOLUTION: The method for freeze-drying Cortinellus shiitake includes irradiating Cortinellus shiitake with an ultraviolet light for 20 minutes to 1 hour, hot-air drying the Cortinellus shiitake with hot air at 30-40°C for 1-2 hours, rapidly freezing the Cortinellus shiitake at -35 to -45°C for 10 minutes-1 hour and freeze-drying the rapidly frozen Cortinellus shiitake at -35 to -45°C in a vacuum state of 40-50×10<SP>-3</SP>torr for 21 to 48 hours. The method is expected to simultaneously have merits of freeze-drying to maintain the external shape of raw Cortinellus shiitake as it is during drying and to quickly restore Cortinellus shiitake to an original form in water during use and effects of increasing a vitamin D content by ultraviolet irradiation and flavor and fragrance of Cortinellus shiitake. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for freeze-drying shiitake mushrooms. More specifically, after shiitake is irradiated with ultraviolet rays and dried with hot air in a short time, the shiitake mushrooms are rapidly frozen and lyophilized under reduced pressure to obtain shiitake mushrooms. The present invention relates to a method for freeze-drying shiitake mushrooms that can be dried while maintaining the outer shape without being shrunk, that can easily cook dried shiitake mushrooms, and that can enhance the content and the taste and aroma of shiitake mushrooms.

In general, shiitake mushroom (Pyogo mushroom, Shiitake mushroom, Lentinus edodes) contains various nutrients including various amino acids and ergosterol in a well-balanced manner, has a unique taste and aroma, and has an anticancer effect. It's known that there is an increase in consumption.

On the other hand, shiitake mushrooms are high in moisture content, tend to be soft and difficult to maintain a fresh state for a long period of time, and have a limited production period, so most shiitake mushrooms are stored and distributed in a dry state. Shiitake mushrooms are usually dried using natural sun-drying or hot-air drying using hot air. The dried shiitake mushrooms are used after cooking in their original form by pouring them into water. .

However, in the conventional drying method of shiitake mushrooms, in the case of the sun drying method, low quality deterioration such as scattering of spore spores, colloidalization of sputum cell tissue, tissue deformation due to contraction, gloss, etc. In the case of the drying method as well, the quality of the tissue deteriorates due to the shrinkage of the tissue due to shrinkage. In particular, when hot air drying is performed at a temperature lower than 45 ° C., spores are scattered and shiitake mushrooms open and the tip is wound. In addition, there is a problem that, when hot-air drying is performed at a high temperature of 55 ° C. or higher, fresh shiitake mushrooms having a high water content are damaged by heat and boiled.

In addition, the denser the shiitake mushroom is, the richer the nutrients, the better the chewing taste, and the better the quality, but the shiitake is dried by the conventional sun drying method and hot air drying method described above. Consumers prefer low-quality shiitake over high-quality shiitake because the less dense shiitake mushrooms are quickly restored to their original form in water and are easier to use. For this reason, such a conventional drying method has not only the problem of the drying method itself but also the problem that high-quality shiitake mushrooms are disliked by consumers.

The present invention has been made in view of such circumstances, and its purpose is that there are no problems such as sputum spore scattering, sputum cell tissue colloid, tissue deformation due to contraction, shiitake deformation, thermal damage, etc. The best way to maintain the original shape of raw shiitake mushrooms is to quickly restore them to their original form in water during cooking, and to improve the usability of the dried shiitake mushrooms. It is to provide a drying method that can.

In order to achieve the above object, the shiitake lyophilization method according to the present invention includes an ultraviolet irradiation step, a hot-air drying step, a quick freezing step, and a reduced-pressure lyophilizing step in addition to the usual sorting and cutting steps. It is characterized by.

              According to the present invention, after the shiitake is irradiated with ultraviolet rays and then dried with hot air in a relatively short time, the shiitake is rapidly frozen and freeze-dried under reduced pressure, so that the outer shape of the raw shiitake is maintained to the maximum during the drying process. At the time of cooking, it is quickly restored to its original form in water and not only is it easy to use, but in particular, it can increase the content of vitamin D and the taste and aroma of shiitake mushrooms. This is expected to contribute to the improvement of farmers' income by promoting consumption of shiitake as well as providing consumers with high-quality shiitake and improving consumption satisfaction.

Hereinafter, a configuration according to a preferred embodiment of the present invention will be described in detail.

The shiitake lyophilization method according to the present invention may selectively include a normal sorting step and a cutting step, and the sorting step includes a normal sorting step for classifying raw shiitake mushrooms according to their form, size, damage state, and the like. means. The shiitake mushrooms that have been subjected to the selection step may be used as they are, but may further include a cutting step of cutting into slices or squares, and the thickness of shiitake is used during the cutting step. Depending on the purpose, it is preferably cut to about 3 to 5 mm.

Hereinafter, in the ultraviolet irradiation process as a characteristic process of the present invention, shiitake mushrooms selectively subjected to the sorting and cutting processes are placed in a normal ultraviolet irradiation apparatus or a closed room provided with a normal ultraviolet irradiation apparatus for 20 minutes to 1 minute. When ultraviolet rays are irradiated to the living shiitake mushrooms in a time interval, the original shape of shiitake mushrooms is reduced by impacting the koji molds that transmit the ultraviolet rays and stopping or killing koji molds. It can be maintained for a long time, and can further increase the content of vitamin D contained in shiitake mushrooms.

That is, shiitake contains a large amount of a precursor component called ergosterol, but when the ergosterol is subjected to ultraviolet rays, it is converted into an active form called ergocalciferol and functions as vitamin D. It becomes like this. This vitamin D regulates the absorption and utilization of calcium and phosphorus in the body to maintain the homeostasis of calcium and phosphorus in the body, and is involved in the normal development of the skeleton and teeth. Vit. D ₂ and Vit. Changes in B ₂ content (Journal of Korean Society for Food and Lifestyle, Vol. 16, No. 5 (2001), P463-469) Reference}.

Hereinafter, the hot air drying process according to the present invention does not completely dry the fresh shiitake mushrooms by drying for 8 to 24 hours or more with hot air of 45 to 55 ° C. as in the prior art, and is about 1 to 2 hours at 30 to 40 ° C. Therefore, it is possible to enhance the taste and aroma unique to shiitake without causing problems such as shrinkage of raw shiitake mushrooms and tissue changes caused by the conventional hot air drying method.

That is, guanylic acid, a flavor component of shiitake mushroom, and lenthionine, a fragrance component, are produced from proteins and saccharides in the cocoon, and the optimum temperature is 30-40 ° C. By taking into account the fact that shiitake is dried temporarily with hot air, the disadvantages of hot air drying can be eliminated and only the benefits can be taken {Studies on hot air drying kinetics of shiitake (Korean spirit food magazine, 10 (1 ), 1981. P53-60) Reference}.

The quick freezing step is a step of rapidly freezing shiitake mushrooms that have been subjected to the ultraviolet irradiation step and hot air drying in an environment of −35 to −45 ° C. for 10 minutes to 1 hour. Can maintain the shape of shiitake before freezing.

The reduced pressure freeze-drying step is a step of drying the rapidly-frozen shiitake mushrooms in an environment of −35 to −45 ° C. in a vacuum state of 40 to 50 × 10 ⁻³ torr for 21 to 48 hours. The residual moisture content can be dried to 1 to 12% to prevent the growth of Aspergillus and can be stored for a long time without altering shiitake mushrooms.

On the other hand, in the reduced-pressure lyophilization step, shiitake cut into slices is dried for 24 to 30 hours, shiitake cut into squares is dried for 30 to 36 hours, and shiitake mushrooms that are dried without being cut are 36 to 36. It is preferable to dry for 48 hours.

Shiitake mushrooms dried by the above method can maintain the same outer shape as before drying by rapidly freezing shiitake mushrooms and freeze-drying under reduced pressure, and the dried shiitake tissue is porous. In addition to being able to be restored to the original form in a short time, the content of vitamin D and the unique taste and aroma of shiitake can be enhanced by the ultraviolet irradiation process and the hot air drying process.

Claims (1)

In the shiitake lyophilization method,
Ultraviolet irradiation process in which raw shiitake is irradiated with ultraviolet rays for 20 minutes to 1 hour, killing koji molds and producing vitamin D;
After the ultraviolet irradiation step, the shiitake is dried with hot air at 30 to 40 ° C. for 1 to 2 hours, and a hot air drying step for enhancing the taste and aroma unique to shiitake,
A quick freezing step of freezing the hot air dried shiitake at −35 to −45 ° C. for 10 minutes to 1 hour to maintain the outer shape;
A vacuum freeze-drying step of drying the quick-frozen shiitake mushrooms at −35 to −45 ° C. in a vacuum state of 40 to 50 × 10 ⁻³ torr for 21 to 48 hours to obtain a water content of 1 to 12%. A method for freeze-drying shiitake mushrooms.