CA1251686A - Dried mushrooms and a drying method for the same - Google Patents

Dried mushrooms and a drying method for the same

Info

Publication number
CA1251686A
CA1251686A CA000477876A CA477876A CA1251686A CA 1251686 A CA1251686 A CA 1251686A CA 000477876 A CA000477876 A CA 000477876A CA 477876 A CA477876 A CA 477876A CA 1251686 A CA1251686 A CA 1251686A
Authority
CA
Canada
Prior art keywords
drying
vacuum
mushrooms
vacuum drying
vessel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000477876A
Other languages
French (fr)
Inventor
Ichio Asai
Makoto Ookishima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of CA1251686A publication Critical patent/CA1251686A/en
Expired legal-status Critical Current

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  • Storage Of Fruits Or Vegetables (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

ABSTRACT
Whole mushrooms or mushrooms sliced about 1-5 mm thick, are placed in a vacuum drying vessel and subjected to vacuum drying with the vacuum drying vessel evacuated by a vacuum pump to a high vacuum of about 10-4 mmHg. The vacuum drying is more effective if the air inside the vacuum drying vessel is evacuated by a vacuum pump via a cooling trap being cooled by a cooling device.

Description

5~6 DRIED MUSHROOMS AND A DRYING METHOD THEREFOR
Mushrooms will change in appearance and chemical composi-tion with time, resulting in lowered trade valueO As to the change, mushrooms are subject to putrefaction by bacteria, autodigestion by various enzymes, and chemical attack by oxygen or other gases in air, sunlight, heat, moisture, etc.
Against these causes, various methods for storage have been made available. Typical methods for storage are the method for storage by sterilization embodied by canning, bottling, salting, etc., that by suppression embodied by freezing and carbon-dioxide sealing, and that by drying, embodied by sunlight and fire dryings, etc.
The method for storage by sterilization has a disadvantage that both flavor and original color will be lost. Salting leads even to loss in original taste. Thus, the method for storage by sterilization should be regarded as a means for emergency effective merely for preventing putrefaction for long-term preservation. This method, when applied to mush-rooms such as Tricholoma Matsutake (ITO et IMAI.) SIMG.
= `:
and Tricholoma ponderosum (PECK.) SING. with which flavor _ and appearance are important, leads to loss in trade value.
The suppression storage via freezing or carbon-dioxide sealing has various problems in that mushrooms which are raw are heavy, are inconvenient to transport from producing to consuming districts, and are apt to deteriorate during transportati`on.

, ~?

Si~i86 The sunlight or fire drying method, though in wide use for the storage of Lentlnus edodes (BERK.l SING., has a dis-advantage that oxidation, discoloration, contraction, deforma-tion, and flavor loss occur.
Another method called rapid freeze drying has recently been made available as a drying method for materials to be added to instant foods. This method of rapid freeze drying was tested for its applicability to mushrooms, but since a mushroom is a rhizomorph composed of hypha fibers, the pressure which water exerts when frozen was found to cause a rhizomorph to be cracked up to destruction.
In view of the disadvantages of the various methods for storage described above, the present inventor has made extensive research for an effective method for storage capable of preserving, with practically no loss in flavor or discolora-tion, mushrooms such as Tricholoma Matsutake (ITO. et IMAI.) SING. and Tricholoma ponderosum (PECK.) SI~NG. with which flavor and appearance are important.
According to the present invention dried mushrooms are prepared by vacuum drying.
According to one embodiment the inventive method is characterized in that whole mushrooms or in slices 1-5 mm thick are subject to vacuum drying. Preferably the vacuum drying is continued to a water content of about 0.2% under a high vacuum of about 10 mmHg.

lZ5:~i8~

Conveniently the mushrooms are placed in a vacuum drying vessel, the air inside which is then evacuated by a vacuum pump via a cooling trap being cooled by a cooling device.
The following is. a description by way of example of an embodiment of the present invention reference being had to the accompanylng drawings in which:
FIGURE 1 illus,trates an example of a vacuum drying apparatus.
A suitab,le emb.odiment of the present invention will be described in detail.
FIGURE 1 shows. a vacuum drying apparatus 10. A
vacuum drying vessel 12 is at room temperature. A cooling trap 14 is connected to the vacuum drying ves.sel 12 via an air suction tube 16. and also to a vacuum pump 20. via an air suction tube 18. A cooling device 22 i.s. capable o~
cooling the inside of the cooling trap 14 down to 0.C. The air suction tubes 16 and 18 are provided with valves. 24 and 26, respect~veIy.
20. A mushroom to be dried is placed in the. vacuum drying vess-eI 12 and the vacuum pump 20 is put into operation to evacuate the inside air from the vessel 12 via the suction tube 16 7 cooling trap 14, and air suction tube. 18O The mush-room will get rid of its water, gradually to dryness. The water vapor coming from the mushroom is mostly condens.ed in the cooling trap 14, partly taken out through the vacuum pump 20.

51~

The condensation oE water vapor by the cooling trap 14 causes the pressure of inside water vapor to be lowered, accelerating the vaporization or drying o~ the mushroom. In an embodiment of the present invention, the air inside the vacuum dry-ing vessel 12 may be evacuated directly by the vacuum pump 20 with the cooling trap omitted. In such a case, however, the drying speed is more or less lowered and the vacuum pump 20 needs to be kept running. I~ the vacuum pump 20 gets stopped when a high vacuum has been reached inside the vacuum drying vessel 12, the ~ater vapor pressure inside the vacuum drying vessel 12 is caused to go up gradually until the vaporization of water ~rom the mush-room is stopped. Thus, insu~ficient drying may occur and the cessation of water vaporization will result in discolora-tion and contraction of the mushroom.
With the cooling trap 14 provided, the mushroom may be dried with increased speed as noted above, and also energy saving may be effected by stopping the vacuum pump 20 when the inside of the vacuum drying vessel 12 has reached a high vacuum. This is because, even if the valve 26 is closed and then the vacuum pump 20 is stopped when a high vacuum has been reached inside the vacuum drying vessel 12, the water vapor, which has~ been vaporized out into the vacuum drying vessel 12, is allowed to condense in the cooling trap 14, which condensation will induce further vaporization of water from the mushroom.

i~Sl~R6 The vaporization of water deprives the mushroom of the heat of vaporization~ This causes the mushroom to cool down to about 0C, sometimes to a temperature as low as -5C. By this- stage most water has been vapoxized out, with the mushroom almost completely dried. Thus, water is not caused to freeze so rapidly as to crack rhizomorphs, as in the rapid freeze drying mentioned above, with a result that the mushroom is favorably dried with its original shape preserved. During the latter half of the drying process by which time most ~ater has been vaporized out, the tempera-ture of the mushroom will again go up. In the vacuum drying where the temperature will change as described above, decomposi-tion of flavor or taste components due to freezing will not occur and, in contrast to drying by sunlight or fire, drying proceeds under such a reduced oxygen pressure that any dis-coloration due to oxidation does not occur.
Whole mushrooms may be dried sufficiently by ~acuum drying.
With mushrooms; sliced to 1-5 mm in thickness, the drying 2a time may conveniently ~e shortened to a great extent since the surface area has been increased with the travelling dis-tance of water decreased.
The present invention is especially suitable for Tricholoma ~atsutake (ITO. et IMAI.) SING, Trlcholoma pon-derosum (PECK.) SING., Lentlnus edodes (BERK.) SING., and .
LyophyLlum aggregatum (SCHAFF. et SACH.) K~HNER.

8~;

Several embodiments of the present invention are given below.
Example 1 Whole mushrooms were placed in a vacu~n drying vessel at room temperature and the vessel was evacuated by a vacuum pump and kep-t at a high vacuum 10 4 mmHg for 48 hours. The mushrooms were ~ound dried to a water content of 0.2~, indi-cating no state of having been frozen.
Example 2 At room temperature, mushrooms were sliced to 5 mm in thickness and placed in a vacuum drying vessel. This vessel was evacuated and kept at a high vacuum 10 4 mmHg for 36 hours. The sliced mushrooms were found dried to a water content of 0,.2%, indicating no state of havin~ been frozen.
Example 3 At room temperature, mushrooms were sliced to 1-3 mm in thickness and placed in a vacuum drying vessel. This vessel was evacuated and kept at a high vacuum 10 4 mmHg for 24 hours. The sliced mushrooms were found dried to a water content of 0.2%, indicating no state of having been frozen.
In the examples 1~3, the whiteness, of mushroom was maintained, no di,scoloration being found at all. Almost no indication was found of cracks in rhizomorphs, contraction, or shape change. When the dried material was, recovered by being ~i,ven water, and cooked, both its flavor and tooth touch were found the same as before drying; the sweetness was found rather increased by the drying.

l3t;

As described above, the present invention, which provides vacuum drying, a drying method not severe for mush-rooms, has a significant advantage that drying results in virtually no loss of flavor~ increase in sweetness, no dis-coloration, and neither cracks on rhizomorph nor contraction which deforms the shape, and is especially suitable for Tricholoma Matsutake (ITO. e-t I~AI.) SING. and Tricholoma ponderosum (PECK.) SING. with which the appearance is important.
=
The present invention has another significant advantage that the dried product has such a high durability that fresh mush-rooms may be supplied all the year round.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A drying method for fruits body of Tricholoma Matsutake (Ito. et Imai.) Sing. comprising steps of:
slicing fruits body of Tricholoma Matsutake (Ito. et Imai.) Sing. to form pieces sliced whose thickness are 1mm?5mm;
and drying said pieces sliced up to about 0.2% of water content under a condition of high vacuum condition such as about 10-4mmHg in a vacuum drying vessel.
CA000477876A 1984-03-30 1985-03-29 Dried mushrooms and a drying method for the same Expired CA1251686A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59063917A JPS60207546A (en) 1984-03-30 1984-03-30 Dried fungal mushroom and method for drying
JP59-63917 1984-03-30

Publications (1)

Publication Number Publication Date
CA1251686A true CA1251686A (en) 1989-03-28

Family

ID=13243170

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000477876A Expired CA1251686A (en) 1984-03-30 1985-03-29 Dried mushrooms and a drying method for the same

Country Status (2)

Country Link
JP (1) JPS60207546A (en)
CA (1) CA1251686A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05298511A (en) * 1992-04-22 1993-11-12 Nippon Avionics Co Ltd Ticketless parking area managing device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS519378B2 (en) * 1972-12-21 1976-03-26
JPS5441345A (en) * 1977-09-06 1979-04-02 Kubutsu Shiyokuhin Kougiyou Kk Production of dried *shiitake* slices

Also Published As

Publication number Publication date
JPH0258900B2 (en) 1990-12-11
JPS60207546A (en) 1985-10-19

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