AU2021201901A1

AU2021201901A1 - Method for increasing content of vitamin d2 in mushrooms and method for preparing edible mushroom powder

Info

Publication number: AU2021201901A1
Application number: AU2021201901A
Authority: AU
Inventors: Sheng CAO; Yun Liang; Shenjian WANG
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-18
Filing date: 2021-03-26
Publication date: 2022-01-20
Anticipated expiration: 2041-03-26
Also published as: AU2021201901B2; CN111642733A; KR20210156727A; WO2021253841A1; KR102577063B1

Abstract

This disclosure relates to nutritional foods, and more particularly to a method for increasing a content of vitamin D 2 in a mushroom and a method for preparing an edible mushroom powder. The cell membrane of an ergosterol-containing mushroom is exposed to an ultraviolet light to increase the content of vitamin D 2 . In the preparation of an edible mushroom powder, the ergosterol-containing mushroom is irradiated with ultraviolet light and then dried to obtain the edible mushroom powder. By exposing the cell membrane of the mushroom to ultraviolet light, the intensity and efficiency of the ultraviolet radiation are significantly improved, thereby effectively improving the conversion rate of ergosterol into vitamin D2 and increasing the content of vitamin D2 in the mushroom.

Description

METHOD FOR INCREASING CONTENT OF VITAMIN D 2 IN

MUSHROOMS AND METHOD FOR PREPARING EDIBLE MUSHROOM POWDER TECHNICAL FIELD

This disclosure relates to nutritional foods, and more particularly to a method for

increasing a content of vitamin D 2 in mushrooms and a method for preparing an

edible mushroom powder.

BACKGROUND

Currently, the plant-derived vitamin D 2 is mainly prepared by converting

ergosterol in mushrooms into vitamin D 2 to obtain mushroom powder rich in vitamin

D 2 or extracting vitamin D 2 from a mushroom powder with vegetable oil to obtain a

mushroom oil containing vitamin D 2 . The mushroom powder and mushroom oil have

been gradually used in the preparation of gum candies, soft capsules, tablet candies,

solid beverages, infant formula foods and health food.

It has been reported on the process for promoting the conversion of ergosterol

into vitamin D 2 using ultraviolet light. Specifically, the fresh mushrooms are cleaned,

sliced, radiated under ultraviolet light, dried and ground to obtain a mushroom powder

rich in vitamin D 2, and then the vitamin D 2 can be extracted from the mushroom

powder with vegetable oil to produce the mushroom oil containing vitamin D 2 .

However, this process has a poor conversion rate of ergosterol into D 2 , and thus the

content of vitamin D 2 in the obtained mushroom powder is not desirable, resulting in a

high production cost of vitamin D 2 .

SUMMARY

An object of this disclosure is to provide a method for increasing a content of

vitamin D 2 in a mushroom and a method for preparing an edible mushroom powder to

overcome the defect of low conversation rate of ergosterol into vitamin D 2 in

mushrooms in the prior art.

Ergosterol is a main component of the cell membrane of mushrooms, and is

wrapped by the cell wall. The conversion rate of ergosterol into vitamin D2 under the

ultraviolet radiation is directly related to temperature, morphological structure and

moisture content. Unfortunately, the ultraviolet light has an undesirable penetration,

only 30-80 m, which is equivalent to 6-13 cell layers. Although the slice treatment

has been adopted in the prior art, the contact area between the ultraviolet light and cell

membrane is still insufficient, failing to effectively enhance the conversion rate of

ergosterol.

Technical solutions of this disclosure are specifically described as follows.

In a first aspect, the present disclosure provides a method for increasing a content

of vitamin D 2 in a mushroom, comprising:

irradiating cell membranes of an ergosterol-containing mushroom with

ultraviolet light.

In some embodiments, the step of irradiating cell membranes of an

ergosterol-containing mushroom with an ultraviolet light comprises:

(1) subjecting the ergosterol-containing mushroom to grinding and wall-breaking

to obtain a mushroom powder; and

(2) suspending the mushroom powder obtained in step (1) in a fluid to produce

fluidized suspension; and irradiating the fluidized suspension with ultraviolet light.

In some embodiments, in step (1), the mushroom is a fresh mushroom, and a

particle size of the mushroom powder is 30-400 [m; preferably 30-200 [m.

In some embodiments, in step (1), the wall-breaking is performed by a

mechanical method or enzymatic digestion.

In some embodiments, the enzymatic digestion is performed in the catalysis of an

enzyme selected from the group consisting of cellulase, pectinase, protease, chitinase

and a combination thereof;

preferably, the protease is selected from the group consisting of papain, neutral

protease, flavourzyme and a combination thereof; and the pectinase is selected from

the group consisting of pectin hydrolase, pectin lyase, pectin esterase, protopectinase

and a combination thereof.

In some embodiments, the step (1) further comprises: adjusting the mushroom powder to a moisture content of 35-85% by plate pressure filtration or centrifugation; preferably, the mushroom powder is adjusted to a moisture content of 35-65%. In some embodiments, the step (2) comprises: suspending the mushroom powder in compressed air by top blowing to produce fluidized suspension; and feeding the fluidized suspension into a vibrating fluidized bed reactor or a boiling fluidized reaction tower; wherein the vibrating fluidized bed reactor and the boiling fluidized reaction tower are respectively provided with an ultraviolet lamp. In some embodiments, the irradiation with ultraviolet light is performed at a temperature below 55°C and a radiation dose of 0.3-3.5 kJ/m2 for less than 240 min; a moisture content of the ergosterol-containing mushroom is not less than 25%; and the ultraviolet light is derived from an ultraviolet B (UV-B) light with a wavelength of 280-315 nm. preferably, the irradiation with ultraviolet light is performed at 30-45° for less than 120 min; and the moisture content of the ergosterol-containing mushroom is 35-65%.

In a second aspect, the present disclosure provides a method for preparing an edible mushroom powder containing vitamin D 2 , comprising: processing an ergosterol-containing mushroom according to the above-mentioned method followed by drying to obtain the edible mushroom powder. In a third aspect, the present disclosure provides an edible mushroom powder prepared by the above-mentioned method, wherein a content of vitamin D 2 in the edible mushroom powder is not less than 15000 IU/g. In a fourth aspect, the present disclosure provides a use of the above-mentioned edible mushroom powder in the preparation of a food, wherein the food is a functional food or a health food. The beneficial effects of the present disclosure are described as follows.

1. In this disclosure, the cell wall of the mushroom sporocarp is broken to expose the ergosterol-containing cell membrane to ultraviolet light, which allows for

enhanced radiation intensity and efficiency, effectively improving the conversion rate

of ergosterol into vitamin D 2 and increasing the content of vitamin D 2 in the

mushroom.

2. The mushroom sporocarp is ground into power, and the powder is suspended

in a fluid to produce a fluidized suspension for ultraviolet light radiation, which

further improves the contact area between the mushroom powder and ultraviolet light,

improving the efficiency of ultraviolet radiation and increasing the conversion speed

and rate of ergosterol into vitamin D 2 . Meanwhile, the radiation temperature and time,

and the moisture content of the mushroom powder are controlled during the

ultraviolet radiation, so as to prevent the vitamin D 2 precursor from converting into

inactive substances such as photosterol and tachysterol, and effectively enhance the

conversion of ergosterol into vitamin D 2 to increase the content of vitamin D 2 in the

edible mushroom powder.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further described with reference to the

accompanying drawings. It should be understood that the drawings are merely

illustrative, and are not intended to limit the disclosure.

FIG. 1 schematically depicts a structure of a vibrating fluidized bed reactor in

accordance with an embodiment of the present disclosure; and

FIG. 2 schematically depicts a structure of a boiling fluidized reaction tower in

accordance with an embodiment of the present disclosure.

In the drawings, 1, upper box body; 11, air outlet; 12, feed inlet; 2, lower box

body; 21, feed outlet; 22, air inlet; 3, screen frame; 4, ultraviolet lamp; 5, tower body;

6, transportation device; 7, air input device; 8, air output device; and 9, ultraviolet

radiation chamber.

DETAILED DESCRIPTION OF EMBODIMENTS

It should be noted that endpoints and values within ranges disclosed herein are

only exemplary, and are intended to include any values close to these values. Any

possible combination of numerical values within the range to form one or more new

ranges should be considered to be expressly disclosed in this disclosure.

In a first aspect, this disclosure provides a method for increasing a content of

vitamin D 2 in a mushroom, which includes irradiating cell membranes of an

ergosterol-containing mushroom with ultraviolet light.

The ergosterol-containing cell membranes are exposed to ultraviolet light, that is

breaking cell walls of the mushroom sporocarp and exposing the cell membranes

originally wrapped by the cell wall to ultraviolet light. The process increases the

intensity and efficiency of the ultraviolet radiation, improving the conversion rate of

ergosterol into vitamin D 2 in the mushroom. After being irradiated with ultraviolet

light, the mushroom can be used to prepare edible mushroom powders, vitamin

D 2-containing mushroom oil and other products rich in vitamin D 2 .

In some embodiments, the step irradiating cell membranes of an

ergosterol-containing mushroom with ultraviolet light includes: (1) subjecting the

ergosterol-containing mushroom to grinding and wall-breaking to obtain a mushroom

powder; and (2) suspending the mushroom powder obtained in step (1) in a fluid to

produce a fluidized suspension; and irradiating the fluidized suspension with

ultraviolet light.

The mushroom powder is suspended in a fluid to produce a fluidized suspension

and the fluidized suspension is irradiated with ultraviolet light. The surface of the

mushroom powder is fully exposed to the ultraviolet light. Therefore, the contact area

between the mushroom powder and ultraviolet light is increased, improving the

efficiency of irradiation and accelerating the conversion of ergosterol into vitamin D 2 .

The crushing process can be performed using any crushing method and equipment. In

an embodiment, a beater is used to crush the fresh mushroom and the ultraviolet light

is provided by an ultraviolet lamp.

In some embodiments, in step (1), the mushroom is a fresh mushroom, and a particle size of the mushroom powder is 30-400 [m; specifically 30 m, 60 m, 90 ptm, 120 jm, 150 [m, 170 jm, 190 jm, 200 jm, 250jm, 300 jm, 350jm, 400 m and any value in a range formed by any two of these point values; preferably 30-200 pm. In a preferred embodiment, the conversion rate of ergosterol into vitamin D 2 is further improved.

In some embodiments, the fresh mushroom is selected from the group consisting

of Agaricus bisporus, Lentinus edodes, Pleurotus ostreatus, Flammulina velutipes,

Auricularia auricula and a combination thereof. The fresh mushroom needs to be

refrigerated below 15°C within 2 days after being harvested, and is subjected to

impurity removal and cleaning before use.

In some embodiments, in step (1), the wall-breaking is performed by a

mechanical method or enzymatic digestion.

Specifically, the mechanical wall-breaking can be performed using a colloid mill,

a sand mill or a homogenizer. Preferably a high-pressure homogenizer is used to

homogenize the mushroom powder 2-3 times at a pressure of 20-80 MPa. A weight

ratio of an enzyme and the mushroom powder in the enzymatic digestion is 2-5:1000.

The enzymatic digestion is performed at 35-55°C for 2-4 h. In a preferred

embodiment, a rate of a secondary crushing to the crushed mushroom powder is

improved.

The enzyme used in the enzymatic digestion is not specifically limited, as long as

it can degrade the cell wall of the mushroom. The main component of the cell wall of

mushrooms is chitin. In some embodiments, the enzyme used in the enzymatic

digestion is selected from the group consisting of cellulase, pectinase, protease,

chitinase and a combination thereof. The cellulase is a multi-component enzyme

system with a synergistic effect, belonging to a composite enzyme, and mainly

includes exo-p-glucanase, endo-p-glucanase and p-glucosidase.

and a combination thereof. In a preferred embodiment, a rate of the enzymatic digestion is improved. In some embodiments, the step (2) includes suspending the mushroom powder in compressed air by top blowing to produce fluidized suspension; and feeding the fluidized suspension into a vibrating fluidized bed reactor or a boiling fluidized reaction tower. The vibrating fluidized bed reactor and the boiling fluidized reaction tower are respectively provided with an ultraviolet lamp. In a preferred embodiment, by means of the vibrating fluidized bed reactor or the boiling fluidized reaction tower, the surface of the mushroom powder can be in contact with the ultraviolet light, and the cell membrane of the mushroom can be fully exposed to ultraviolet light, further improving an efficiency of ultraviolet irradiation and increasing a conversion rate of ergosterol into vitamin D 2 in the mushroom. Referring to Fig. 1, a vibrating fluidized bed reactor provided herein includes an upper box body 1 and a lower box body 2. A screen frame 3 is provided between the upper box body 1 and the lower box body 2. Ultraviolet lamps 4 are evenly provided on an inner wall of the upper box body 1. A top of the upper box body 1 is provided with an air outlet 11. A feed inlet 12 is provided above one side of the screen frame 3, and a feed outlet 21 is provided below the other side of the screen frame 3. An air inlet 22 is provided on the lower box body 2. The material is transported to the screen frame 3 through the feed inlet 12, and the air is introduced through the air inlet 22 to suspend the material in the upper box body 1. At this time, the ultraviolet lamps 4 are turned on to radiate the material. After the irradiation is completed, the material is output from the feed outlet 21. Fig. 2 shows a structure of a boiling fluidized reaction tower of the present disclosure, which includes a tower body 5 and a transportation device 6 communicated with a bottom of the tower body 5. A bottom wall of the tower body 5 is provided with an air input device 7, and a top of the tower body 5 is provided with an air output device 8. An ultraviolet radiation chamber 9 is provided in the tower body 5, and two layers of ultraviolet lamps 4 are provided in the ultraviolet radiation chamber 9. The material is transported to the tower body 5 through the transportation device 6, and the air is introduced through the air input device 7 to make the material in a boiling-like state, suspending the material in the tower body 5.

The ultraviolet lamps 4 are turned on to radiate the material. After the irradiation is

completed, the material is output from the material truck 6.

In some embodiments, the irradiation with ultraviolet light is performed at a

temperature below 55°C and a radiation dose of 0.3-3.5 kJ/m2 for less than 240 min; a

moisture content of the ergosterol-containing mushroom is not less than 25%; and the

ultraviolet light is derived from an ultraviolet B (UV-B) light with a wavelength of

280-315 nm. Specifically, the radiation dose can be 0.3 kJ/m 2 , 1. kjm 2 , 1.9 kJ/m 2

, 2.7 kJ/m 2, 3.5 kJ/m2 and any value in a range formed by any two of these point values;

and the wavelength of the ultraviolet light source is 280 nm, 290 nm, 300 nm, 310 nm,

315 nm and any value in a range formed by any two of these point values.

Preferably, the irradiation with ultraviolet light is performed at 30-45°;

specifically, 30°C, 35°C, 40°C, 45°C and any value in a range formed by any two of

these point values. The moisture content of the mushroom powder is 35-65%;

specifically, 35%, 40%, 45%, 50%, 55%, 60%, 65% and any value in a range formed

by any two of these point values. T irradiation with ultraviolet light is performed for

less than 120 min. In a preferred embodiment, an efficiency of the irradiation is

further improved.

The moisture content of the mushroom powder needs to be controlled within a

certain range during the irradiation with ultraviolet light. Therefore, in some

embodiments, the step (1) further includes subjecting the mushroom powder to a plate

pressure filtration or centrifugation, so that a moisture content in the mushroom

powder is 35-85%; specifically, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,

80%, 85% and any value in a range formed by any two of these point values;

preferably 35-65%.

In a second aspect, the present disclosure provides a method for preparing an

edible mushroom powder containing vitamin D 2 , which includes processing an

ergosterol-containing mushroom according to the above-mentioned method followed

by drying to obtain the edible mushroom powder.

In some embodiments, the drying process can be pressure spray drying, roller

drying, air spray drying, vacuum freeze drying or any other drying method.

In a third aspect, the present disclosure provides an edible mushroom powder prepared by the above-mentioned method, and a content of vitamin D 2 in the edible mushroom powder is not less than 15000 IU/g. In a fourth aspect, the present disclosure provides a use of the above-mentioned edible mushroom powder in the preparation of a food, and the food is a functional food or a health food. The present disclosure will be described clearly in accompany with the embodiments. In the following examples, the particle size of the powder material is measured using Mastersizer 3000 laser diffraction particle size analyzer produced by Malvern Panalytical Co., Ltd (Holland); the contents of vitamin D 2 and ergosterol are measured according the method in GB14755-2010 by L-7000 high-performance liquid chromatography produced by Hitachi, Ltd (Japan); Agaricus bisporus, Lentinus edodes, and Pleurotus ostreatus are purchased from Shandong Linyi Ruize agricultural technology Co., Ltd; and other raw materials are commercially available.

Example 1 (1) Freshly-harvested Agaricus bisporus was cleaned to remove the residual the culture medium. 5 kg of the Agaricus bisporus was crushed by a beater, added with 10 g of cellulase and 15 g of chitinase and hydrolyzed at 55°C for 2 h to obtain a powder with a particle size of 30-150 [m. (2) The powder obtained in step (1) was subjected to plate-frame pressure filtration to obtain a mushroom powder having a moisture content of 50%. (3) The mushroom powder obtained in step (2) was suspended in a fluid to produce a fluidized suspension, which was then fed into a vibrating fluidized bed reactor and irradiated under ultraviolet light, where the irradiation with ultraviolet light was performed at 35°C and a radiation dose of 2 kJ/m2under a wavelength of 300 nm for 100 min. After the irradiation, the mushroom powder was subjected to vacuum freeze-drying to obtain an edible mushroom powder.

Example 2

(1) Freshly-harvested Lentinus edodes was cleaned to remove the residual of the

culture medium. 5 kg of the Lentinus edodes was crushed by a beater, and then

homogenized 2-3 times at 62°C and 40 MPa by means of a high-pressure

homogenizer to obtain a powder with a particle size of 60-180 [m.

(2) The powder obtained in step (1) was centrifuged by a centrifuge to obtain a

mushroom powder having a moisture content of 35%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

produce a fluidized suspension, which was then fed into a vibrating fluidized bed

reactor and irradiated under ultraviolet light, wherein the irradiation with ultraviolet

light was performed at 30°C and a radiation dose of 0.3 kJ/m2 under a wavelength of

280 nm for 115 min. After the irradiation, the mushroom powder was subjected to

vacuum freeze-drying to obtain an edible mushroom powder.

Example 3

(1) Freshly-harvested Pleurotus ostreatus was cleaned to remove the residual of

the culture medium. 5 kg of the Pleurotus ostreatus was crushed by a beater, and

added with 5 g of papain and 5 g of pectinesterase and hydrolyzed at 35°C for 3.5 h to

obtain a powder with a particle size of 60-200 [m.

(2) The powder obtained in step (1) was subjected to plate-frame pressure

filtration to obtain a mushroom powder having a moisture content of 65%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

produce a fluidized suspension, which was then fed into a boiling fluidized reaction

tower and irradiated under ultraviolet light, where the irradiation with ultraviolet light

was performed at 45°C and a radiation dose of 3.5 kJ/m2 and a wavelength of 315 nm

for 80 min.

(4) The mushroom material obtained in step (3) was mixed with 10 kg of

rapeseed oil in an extraction tank. The extraction tank was vacuumized and then filled

with nitrogen having a purity of more than 99.9%. The extraction was performed at

0.02 MPa and 10°C for 75 h. Then the extraction system was subjected to solid-liquid separation by a plate and frame filter press to obtain an oil containing mushroom-derived vitamin D 2

. Example 4

(1) Freshly-harvested Agaricus bisporus was cleaned to remove the residual of

the culture medium. 5 kg of the Agaricus bisporus was crushed by a beater, and added

with 5 g of chitinase and hydrolyzed at 45°C for 1 h to obtain a powder with a particle

size of 300-400 [m. (2) The powder obtained in step (1) was subjected to plate-frame pressure

filtration to obtain a mushroom powder having a moisture content of 55%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

was performed at 40°C and a radiation dose of 2.5 kJ/m2 under a wavelength of 290

nm for 90 min. After the irradiation, the mushroom powder was subjected to

heated-air drying to obtain an edible mushroom powder.

Example 5

(1) Freshly-harvested Agaricus bisporus was cleaned to remove the residue of

with 5 g of flavourzyme and 10 g of protopectinase and hydrolyzed for 2 h to obtain a

powder with a particle size of 30-150 [m.

(2) The powder obtained in step (1) was subjected to plate-frame pressure

filtration to obtain a mushroom powder having a moisture content of 25%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

at 35°C and a radiation dose of 2.5 kJ/m2 under a wavelength of 290 nm for 90 min.

After the irradiation, the mushroom powder was subjected to heated-air drying to

obtain an edible mushroom powder.

Example 6

(1) Freshly-harvested Agaricus bisporus was cleaned to remove the residual of

into a sander for breaking cell walls to obtain a powder with a particle size of 30-150

[m.

(2) The powder obtained in step (1) was subjected to plate-frame pressure

filtration to obtain a mushroom powder having a moisture content of 50%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

reactor and irradiated under ultraviolet light, where the irradiation with ultraviolet

light was performed at 52°C and a radiation dose of 1.5 kJ/m2 under a wavelength of

285 nm for 100 min. After the irradiation, the mushroom powder was then subjected

to heated-air drying to obtain an edible mushroom powder.

Example 7

(1) Freshly-harvested Pleurotus ostreatus was cleaned to remove the residual of

added into a sander for breaking cell walls to obtain a powder with a particle size of

30-150 [m.

(2) The powder obtained in step (1) was subjected to plate-frame pressure

filtration to obtain a mushroom powder having a moisture content of 85%.

(3) The mushroom powder obtained in step (2) was suspended in a fluid to

light was performed at 40°C and a radiation dose of 1.8 kJ/m2 under a wavelength of

240 nm for 220 min. The moisture content of the mushroom powder was 65%. After

the irradiation, the mushroom powder was subjected to vacuum freeze-drying to

obtain an edible mushroom powder.

(4) The mushroom material obtained in step (3) was mixed with 10 kg of rapeseed oil in an extraction tank. The extraction tank was vacuumized and then filled with nitrogen having a purity of more than 99.9%. The extraction was performed at

0.02 MPa and 10°C for 75 h. Then the extraction system was subjected to solid-liquid

separation by a plate and frame filter press to obtain an oil containing

mushroom-derived vitamin D 2

. Comparative Example 1

(1) Freshly-harvested Agaricus bisporus was cleaned to remove the residual of

into a sander for breaking cell walls obtain a powder with a particle size of 5-10 [m.

(2) The powder obtained in step (1) was irradiated under ultraviolet light, where

the irradiation with ultraviolet light was performed at 35°C and a radiation dose of 2

kJ/m2 under a wavelength of 300 nm for 100 min. The moisture content of the

mushroom powder was 50%. After the irradiation, the mushroom powder was then

subjected to vacuum freeze-drying to obtain an edible mushroom powder.

Comparative Example 2

(1) Freshly-harvested Agaricus bisporus was cleaned to remove the residual of

the culture medium. 5 kg of the Agaricus bisporus was cut into thin slices with a

thickness of 0.8 mm.

(2) The Agaricus bisporus slices obtained in step (1) were irradiated under

ultraviolet light, where the irradiation with ultraviolet light was performed at normal

temperature and normal pressure and a radiation dose of 1.5 J/cm2 under an UV-B

light of 280 nm for 100 min.

(3) After the irradiation, the Agaricus bisporus slices was dried at 60°C in a

hot-air circulating drying box under a nitrogen-filled condition.

(4) The dried Agaricus bisporus slices was subjected to superfine grinding to

obtain an edible mushroom powder with a particle size of 100 mesh.

Comparative Example 3

(1) Freshly-harvested Pleurotus ostreatus was cleaned to remove the residual of

the culture medium. 5 kg of the Pleurotus ostreatus was cut into thin slices with a

thickness of 0.8 mm.

(2) The Pleurotus ostreatus slices obtained in step (1) were irradiated under

temperature and normal pressure and a radiation dose of 1.5 J/cm2 under an UV-B

light of 280 nm for 100 min.

(3) The Pleurotus ostreatus slices obtained in step (2) were crushed into particles

with a particle size of 80-150 mesh, and then were mixed with 10 kg of rapeseed oil in

an extraction tank. The extraction tank was vacuumized and then filled with nitrogen

having a purity of more than 99.9%. The extraction was performed at 0.06 MPa and

25°C for 100 h. Then the extraction system was subjected to solid-liquid separation by

a plate and frame filter press to obtain an oil containing mushroom-derived vitamin

D2 .

Experimental results

The edible mushroom powders or the oils containing mushroom-derived vitamin

D 2 prepared in Examples 1-7 and Comparative Examples 1-2 were detected for

vitamin D 2 content, and the results were shown in Table 1. The mushroom raw

materials in Examples 1-7 and Comparative Examples 1-3 were measured for the

content of ergosterol, and the measurement results were shown in Table 1, where the

dried mushroom was calculated as 20% by weight of the fresh mushroom, and the

ergosterol content was converted by 1 g = 40 IU.

Table 1 Ergosterol content in the fresh mushroom and vitamin D2 content in the

edible mushroom powder/mushroom oil

Vitamin D 2 content in the

Ergosterol content in the fresh edible mushroom Sample mushroom (mg/g) powder/mushroom oil

containing vitamin D 2 (IU/g)

Example 1 0.553 63450

Example 1 0.413 52187

Example 1 0.35 4428.1

Example 1 0.548 18731

Example 1 0.535 23643

Example 1 0.541 21146

Example 1 0.31 1821.9

Comparative Example 1 0.503 14108

Comparative Example 2 0.512 12327

Comparative Example 3 0.34 1108.7

It can be seen from Table 1 that the edible mushroom powders prepared in

Examples 1, 2 and 4-6 were much higher than the edible mushroom powders prepared

in Comparative Examples 1-2 in the vitamin D 2 content. Moreover, the oils prepared

in Examples 3 and 7 were superior to that prepared in the Comparative Example 3 in the vitamin D 2 content. These results demonstrated that the method provided herein can effectively promote the conversion of ergosterol into vitamin D 2 .

The above-mentioned embodiments are only preferred embodiments, and not intend to limit the scope of the disclosure. It should be noted that variations and modifications made by those skilled in the art without departing from the spirit of the disclosure and should fall within the scope of the disclosure defined by the appended

claims.

Claims

CLAIMS What is claimed is:

1. A method for increasing a content of vitamin D 2 in a mushroom, comprising:

irradiating cell membranes of an ergosterol-containing mushroom with

ultraviolet light.

2. The method according to claim 1, characterized in that the step of irradiating

cell membranes of an ergosterol-containing mushroom with ultraviolet light

comprises:

(1) subjecting the ergosterol-containing mushroom to grinding and wall-breaking

to obtain a mushroom powder; and

(2) suspending the mushroom powder obtained in step (1) in a fluid to produce a

3. The method according to claim 2, characterized in that in step (1), the

mushroom is a fresh mushroom, and a particle size of the mushroom powder is

-400 [m.

4. The method according to claim 3, characterized in that in step (1), the particle

size of the mushroom powder is 30-200 [m.

5. The method according to claim 2, characterized in that in step (1), the

wall-breaking is performed by a mechanical method or enzymatic digestion.

6. The method according to claim 5, characterized in that the enzymatic digestion

is performed in the catalysis of an enzyme selected from the group consisting of

cellulase, pectinase, protease, chitinase and a combination thereof.

7. The method according to claim 6, characterized in that the protease is selected from the group consisting of papain, neutral protease, flavourzyme and a combination thereof; and the pectinase is selected from the group consisting of pectin hydrolase, pectin lyase, pectin esterase, protopectinase and a combination thereof.

8. The method according to claim 2, characterized in that the step (1) further

comprises:

adjusting the mushroom powder to a moisture content of 35-85% by plate

pressure filtration or centrifugation.

9. The method according to claim 8, characterized in that in step (1), the

mushroom powder is adjusted to a moisture content of 35-65%.

10. The method according to claim 2, characterized in that the step (2)

comprises:

suspending the mushroom powder in compressed air by top blowing to produce

fluidized suspension; and

feeding the fluidized suspension into a vibrating fluidized bed reactor or a

boiling fluidized reaction tower;

wherein the vibrating fluidized bed reactor and the boiling fluidized reaction

tower are respectively provided with an ultraviolet lamp.

11. The method according to any one of the claims 1-10, characterized in that the

irradiation with ultraviolet light is performed at a temperature below 55°C and a

radiation dose of 0.3-3.5 kJ/m2 for less than 240 min; a moisture content of the

ergosterol-containing mushroom is not less than 25%; and the ultraviolet light is

derived from an ultraviolet B (UV-B) light with a wavelength of 280-315 nm.

12. The method according to claim 11, characterized in that the irradiation with

ultraviolet light is performed at 30-45° for less than 120 min; and the moisture content

of the ergosterol-containing mushroom is 35-65%.

13. A method for preparing an edible mushroom powder containing vitamin D 2

, comprising:

processing an ergosterol-containing mushroom according to the method of any

one of claims 1-12 followed by drying to obtain the edible mushroom powder.

14. The method according to claim 13, characterized in that a content of vitamin

D 2 in the edible mushroom powder is not less than 15000 IU/g.

15. A use of the edible mushroom powder according to claim 14 in the

preparation of a food, wherein the food is a functional food or a health food.