International Journal of Medicinal Mushrooms, Vol. 7, pp. 103-110 (2005)

Notes on Nutritional Properties ofCulinary-Medicinal Mushrooms

Paul Stamets

Fungi Perfecti Research Laboratories, Kamilche Point, Washington, USA

Address all correspondence to Paul Stamets, Fungi Perfecti Research Laboratories, 50 S.E. Nelson Rd., Kamilche Point, WA98584 USA; Stametsl@aol.com

ABSTRACT: Increasingly, mushrooms are being investigated for their role as nutritional foods. How-ever, few studies have been published on their nutritional profiles. The author grew and submitted 20species for thorough nutritional profiling. In addition, the effect of sunlight on the production of vitaminD of indoor-grown mushroom while drying was explored with Lentinus eddoes (Berk.) Singer (shiitakemushroom), Ganoderma lucidum (W. Curt.:Fr.) Lloyd (reishi), and Grifola frondosa (Dicks.:Fr.) S.F. Gray(maitake). Six to eight hours of sunlight exposure stimulated the production of vitamin D from lowlevels of 134,66, and 469 IU, respectively, to 46,000,2760, and 31,900 IU vitamin D, respectively. Themost vitamin D was produced in Lentinus edodes, whose spore-producing lamellae were exposed to thesun. Dried mushrooms also elicited vitamin D production subsequent to sunlight exposure. Vitamin Dis proven as essential for immune function and has now been identified as a major mitigating factor inmany diseases, so the sunlight-activated biosynthesis of vitamin D from ergosterols within mushroomshas substantial implications for the mushroom industry in the context of worldwide health.

KEYWORDS: medicinal mushrooms, nutrition. Food and Drug Administration, vitamin D, ergosterol,ergocalciferol, cholecalciferol.

INTRODUCTION

Healthy nutrition and diet are gaining importance,not only in the everyday life of human beings, butalso in the treatment of chronic diseases. Doctorsworldwide are recognizing that mushrooms are me-dicinal foods rich in nutrition. The Food and DrugAdministration (FDA) has officially designatedmushrooms as "healthy foods." The National Insti-tutes of Health (NIH) is actively testing the effectsof medicinal mushrooms—funding clinical studiesusing mushrooms in adjunct therapies and/or fortreatments of patients afflicted with HIV, cancer.

obesity, and neurological diseases. Few studies onthe nutritional properties of diverse mushrooms havebeen published since Crisan and Sands (1978) (seeDidukh et al., 2004).

Because most fresh mushrooms are 90% water,nutritional analyses based on their dry weightsare more useful when comparing them to otherfoods. Mushrooms are rich in protein, very lowin simple carbohydrates, rich in high-molecular-weight polysaccharides, high in antioxidants, andvery low in fat. They lack cholesterol, vitamin A,or vitamin C. They are a good source of vitamin Bcomplex—riboflavin (B2), niacin (B3), pantothenic

ABBREVIATIONS

FDA: The Food and Drug Administration; HPLC: high-pressure liquid chromatography; IU: an International Unit for

measuring vitamins; NIH: The National Institutes of Health; RDA: recommended daily allowance; UV: ultraviolet

1521-9437/05 $35.00© 2005 by Begell House, Inc. 103

p. STAMETS

acid (B5)—ergosterols (provitamin D2), and mineralssuch as potassium, copper, and selenium. High indietary fiber, edible varieties range from 20% of drymass for Agaricus species such as A. bisporus (but-ton mushroom) to up to 50% in Pleurotus speciessuch as the phoenix oyster (Beelman et al., 2003;Didukh et al., 2004). Mushrooms are good sourcesof essential minerals, especially selenium, copper, andpotassium—elements important for immune func-tion and for producing antioxidants that reduce freeradicals. Mushrooms also contain numerous medici-nal compounds such as triterpenoids, glycoproteins,natural antibiotics, enzymes, and enzyme inhibitorsthat fortify health.

The protein content of mushrooms ranges from3% for the tough, inedible Fomitopsis offidnalis (ViU.:Fr.) Bond, et Singer to 33,34, and 35% for Lentinuseddoes, Pholiota nameko (T. Ito) S. Ito et Imai in Imai,and Agaricus bisporus, respectively. Mushrooms arerich in complex carbohydrates—heavy molecularweight polysaccharides. Our analyses show thatP-glucans range from 8.9% in Agaricus brasiliensisS. Wasser et al., to 14.5% in Grifola frondosa, andto 41% in Ganoderma lucidum. Fat content rangesfrom 0.3 to 4%, with polyunsaturated fats makingup 10-30% of the total dry weight.

A 20 g (dry) or 200 g (wet) serving of fresh Grifolafrondosa, dried in the sun, provides approximately 75calories and 5 g of protein. This serving has 0.8 g offat, made up of about 70% linoleic acid, an essentialomega-6 fatty acid, and up to 15% ergosterol. Sucha serving provides the following percentages of thereference daily intakes or RDIs: 17% selenium, atleast 30% vitamin D, 8% pantothenic acid, 87% nia-cin, 4% thiamine, and 464% potassium.This 2-hand-ful serving provides 10% of the protein needed bya 140-pouad person or 8% needed by a 180-poundperson. (See www.fda.gov/fdac/special/foodlabel/rdichrt.html and http://lstholistic.com/Nutrition/hol_nutr-SONA.htm.)

The FDA states that if 20% of our daily nutri-tional needs are met by consuming a single serving ofcertain food, then that food is rated "excellent"; thatfood is "good" if a single serving supplies 10% of yourneeds. Given the FDA's definition of "healthy foods,"mushrooms rank "good" to "excellent" in several cat-egories of essential nutrients. Since mushrooms are

so versatile—they can be baked, boiled, broiled, orsauteed—they can incorporated into a wide array ofrecipes palatable to the public.

Mushrooms producing enzymes and enzymeinhibitors are useful to medical practitioners andnutritionists composing menus customized fortheir patients. Suites of enzymes are secreted bythe mycelium as extracellular metabolites. Theseenzymes—laccases, cellulases, lignin peroxidases,and manganese superoxide dismutases—are weUknown for their power in decomposing plant fibersand environmental toxins (Sasek et al., 2001). Mush-rooms also produce enzyme inhibitors. Chen et al.(1997) tested many foods for aromatase inhibitorsand found several mushrooms with an especially highconcentration of these substances, which interruptthe conversion of androgens to estrogens, signifi-cant for postmenopausal women at risk for breastcancer. Similarly, some mushrooms inhibit 5 alpha-reductase, an enzyme that converts testosterone todihydro testosterone, which stimulates growth of theprostate. Increases in 5 alpha-reductase are associatedwith the growth of prostate cancer. To AdXe.,Agaricusbisporus inhibits aromatase the most of about a dozenspecies tested (Grube et al., 2001; Chen, 2004).

Western medical practitioners are starting torecommend mushrooms as preventive or adjuncttherapies for fortifying health and dealing wdthseveral medical conditions. Mushrooms are ap-propriate in diets for treating obesity, adult-onset(non-insulin-dependent) type II diabetes, and im-mune disorders. Mushrooms are also some of thebest sources of ergosterols, which are thought toinhibit angiogenesis, the proliferation of blood ves-sels supporting tumors. The biochemical pathwayfor creating ergosterol may have precursors that alsolimit carcinogenesis.

MATERIALS AND METHODS

The mushrooms featured in this study were grovimby the author according to the methods outlined inStamets (2000).The mushrooms were grown indoorswdth minimum natural light exposure (~100 lux) dif-fused through polycarbonate skylights. Mushrooms,upon harvesting, were either dried indoors in dark-

104 International Journal of Medicinal Mushrooms

NUTRITIONAL PROPERTIES OF CULINARY-MEDICINAL MUSHROOMS

ness or, as indicated, exposed to sunlight from 10AM to 4 PM between June and September at FungiPerfecti Research Laboratories, coordinates N.47.14970 & W. 123.03905. Once exposed to sun-light, fruiting bodies were harvested and dried in-doors by commercial dyers or outside under summersun. The products were then subjected to standard-ized HPLC analysis in conformity with the OfficialMethods of Analysis of AOAC International (2000)17th Ed., AOAC International, Gaithersburg,MD,USA, Official Metliod 982.29 (Modified) at WarrenAnalytical Laboratories, Greeley, Colorado.

Influences of Habitat on MushroomNutritional Content

Even within a single mushroom species, nutrient andmineral levels can vary greatly, influenced by habitatand growing medium. For instance, specimens of aparticular strain o£Pleurotus species grown on sawdustare 32% protein and have 89 mg/100 g of niacin; thesame Pleurotus species grown on straw are 27% pro-tein and 54 mg/100 g of niacin. Some mushroomsconcentrate minerals more than others, dependingon where they are cultivated. Beelman (2003), oftheNutrition Research Advisory Panel ofthe AmericanMushroom Institute, found that the region in whichAgaricus bisporus are cultivated causes selenium contentto vary. Crops originating from Texas and Oklahomahave significantly higher concentrations of seleniumthan samples from Florida and Pennsylvania. Thissubject is covered in much more extensive detail in aforthcoming publication (Stamets, 2005).

RESULTS

In order to find out the precise nutritional value ofmushrooms grown on difFerent substrates, we sent aset of samples of our certified organic mushrooms toWarren Laboratories (http://www.warrenlab.coni/associates.htm). The scope of our analyses exceedsthe current FDA's food labeling requirements,since we identify some ingredients significant tothe unique nutritional profiles of mushrooms thatdo not appear on the FDA's list of nutrients. Note

that some nutrients and active medicinal compoundsdegrade v̂ dth time. Some mushroom samples wereup to 1 year in age before testing, stored at roomtemperature (20 °C), in a dark location.

According to the USDA, 84 g of fresh, or about8 g of dried, Agaricus bisporus constitutes a singleserving. To simplify the math for the hungry my-cophile, I rounded the daily serving to 100 g fresh.The following tables were created from the analysesof 100 g samples of (̂ nV^ mushrooms. Each nutrientis listed as a percentage of total mass. To examinethe nutrients in a single daily dietary serving, simplydivide each percentage by 10 to see how much nutri-tion a consumer would get from eating a serving ofthe listed species (Table 1).

Influence of Light Exposure on Vitamin DContent of Mushrooms

Most gourmet and medicinal mushrooms, unlikebutton mushrooms, require light. Light exposureinfluences vitamin content in mushrooms, particu-larly the conversion of ergosterol to provitamin D2.In the human body, UV light transforms calciferol,but not ergosterol, into vitamin D.

We conducted a series of experiments growdng astrain of shiitake on the same substrate under dif-ferent light conditions and achieved some surprisingresults in vitamin D production. The mushroomswere then subjected to standardized HPLC analysisin conformity with the Official Methods of Analysisof AOAC International (2000) 17th Ed., AOACInternational, Gaithersburg, MD, USA, OfficialMethod 982.29 (Modified).

Lentinus edodes that were grown and dried indoorshad only 110 IU vitamin D. (IU is an InternationalUnit for measuring vitamins; 1 IU of vitamin D isequal to 40 ng of vitamin D). Freshly picked indoor-grovvTi shiitake mushrooms, when placed outdoors todry in the sun, produced an astonishing 21,400 IUof vitamin D per 100 g. Mushrooms from the samestrain, when grovm outdoors in sunlight and driedin the dark, produced only 1620 IU. When L. edodeswere dried, gUls facing the sun, the vitamin D soaredto the highest levels tested, 46,000 IU compared to10,900 IU with gills down. Even more surprising

Volume 7, Issues 1&2, 2005 105

p. STAMETS

TABLE 1. Nutritional

Agaricus bisporusPortobello

Agaricus bisporusCrimini

Agaricus brasiliensisBrazilian "Blazei"

Flammulina populicolaEnokitake

Ganoderma lucidumReisbi

Ganoderma oregonenseOregon Polypore

Grifola frondosaMaitake

Hericium erinaceusLion's Mane

Lentinus edodesShiitake

Pholiota namekoNameko

Pleurotus djamorPink Oyster

Pleurotus ostreatusPearl Oyster

P/eurotus ostreatusvar. columbinusBlue Oyster

Pleurotus pulmonariusPboenix Oyster

Pleurotus tuber-regiumKing Tuber

Trametes versicolorKamilche Turkey Tail

Profiles

Cal

ori

es355

340

362

346

376

367

377

375

356

364

356

360

355

355

329

369

of Diverse Mushroom Species

4 P

rote

ing

/100

g

34.44

33.48

35.19

26.59

15.05

13.27

25.51

20.46

32.93

33.65

30.20

27.25

24.64

19.23

14.97

10.97

Fat

g/1

00

g

3.10

2.39

3.39

3.06

3.48

2.52

3.83

5.06

3.73

3.91

2.86

2.75

2.89

2.70

0.31

1.51

Po

lyu

nsa

tura

ted

fat

g/10

0 g

1.43

0.41

1.51

1.08

0.50

0.21

1.12

0.83

1.30

1.01

0.91

1.16

1.05

0.53

0.04

0.27

To

tal

un

satu

rate

d f

atg/

100

g

1.46

0.44

1.72

1.22

1.20

0.48

2.08

1.85

1.36

1.29

0.97

1.32

1.18

0.62

0.05

0.32

Sat

ura

ted

fat

a

g/10

0 g

0.30

0.26

0.37

0.23

0.27

0.01

0.34

0.76

0.22

0.17

0.16

0.20

0.16

0.11

0.02

0.06

Car

bo

hyd

rate

g/10

0 g

r

47.38

46.17

47.70

52.95

71.00

72.79

60.17

61.80

47.60

48.36

52.76

56.53

57.61

63.40

66.68

77.96

Co

mp

lex

carb

oh

ydra

tes

g/1

00

g

24.68

24.27

26.50

30.55

69.30

72.09

41.37

40.90

31.80

29.26

29.66

38.43

35.31

51.60

66.68

76.06

Sug

ars

g/1

00 g

22.70

21.90

21.20

22.40

1.70

0.70

18.80

20.90

15.80

19.10

23.10

18.10

22.30

11.80

0.00

1.90

Die

tary

fib

erg

/100

g

20.90

19.10

21.00

25.80

66.80

72.00

28.50

39.20

28.90

28.10

43.80

33.40

34.10

48.60

65.50

71.30

106 International Journal of Medicinal Mushrooms

NUTRITIONAL PROPERTIES OF CULINARY-MEDICINAL MUSHROOMS

Cho

lest

erol

1:

mg

/100

g

•

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Vita

min

A

;IU

/100g

,

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Thia

min

e (B

i)m

g/1

00 g

0.27

0.23

0.26

0.35

0.06

0.20

0.25

0.16

0.25

0.28

0.26

0.16

0.16

0.10

0.07

0.07

Rib

ofla

vin

(B

2) ;

* "

mg

/100

g

4.13

3.49

2.40

1.69

1.59

1.49

2.61

2.26

2.30

3.06

2.45

2.04

2.14

1.68

0.65

1.06

Nia

cin

(B

3) i

s;;

;^'

••m

g/I

OO

gS

lify

t;-

69.20

38.50

58.50

60.60

12.40

20.90

64.80

11.80

20.40

106.00

65.80

54.30

48.30

23.80

7.30

9.30

Pan

toth

enic

Aci

d (

B5)

mg

/100

g j

12.70

21.70

14.20

10.90

2.70

2.10

4.40

7.40

11.60

17.50

33.20

12.30

13.70

8.80

3.20

1.70

Vita

min ̂'11*̂

'm

g/10

0 9

!

i

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Vita

min

D #

»•

• iu

/i00 9

-li|S

f

235

26

737

113

66

32

460

57

110

38

136

116

214

178

65

62

Cal

cium

;<

mg

/lOO

g

##

23

9

36

14

37

18

31

8

23

18

5

20

3

9

12

34

. C

opper

-"|||

>|I>

mg

/100

g |;

4.33

20.8

4.28

0.61

1.3

1.1

1.88

1.66

1.23

1.6

1.61

1.69

1.19

1.03

0.13

0.65

Iro

n

• ••

ila

;^. •

•'mg/

100'

g'iiip

'':

2.1

4.8

1.9

8.3

13

4.3

7.6

6

5.5

16

11

9.1

5.2

6.5

3.5

8.7

Pot

assi

umm

g/1

00 g

fij

4500

4800

5200

3100

760

850

2300

2700

2700

2500

4600

2700

4400

2600

500

570

Sel

eniu

mm

g/1

00 g

0.415

0.066

0.35

0.054

0.014

0.039

0.056

0.091

0.076

0.103

0.175

0.035

0.083

0.09

0.092

0.007

Sod

ium ;:

mg/

100 g

52

3

43

19

6

2

14

4

18

4

13

48

31

16

2

6

Volume 7, Issues 1 &2, 2005 107

p. STAMETS

TABLE 2. Influence of Sunlight

Species

Shiitake (Lentinusedodes)

Shiitake {Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake {Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Shiitake (Lentinusedodes)

Reishi(Ganodermalucidum)

Reishi(Ganodermalucidum)

Maitake (Grifolafrondosa)

Maitake (Grifolafrondosa)

Form

Fruitbodies

Fruitbodies

Fruitbodies

Fruitbodies

Fruitbodies

Fruitbodies

Fruitbodies

Stem butts

Stem butts

Mycelium

Mycelium

Fruitbodies

Fruitbodies

Fruitbodies

Fruitbodies

on Vitamin D Content in Medicinal Mushrooms

Substrate

Sawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Supplementedsawdust

Rice

Rice

SupplementedSawdust

SupplementedSawdust

Supplementedsawdust

Supplementedsawdust

Growth and drying conditions

Grown in dark, dried in dryer

Grown in dark, dried in dryer

Normal growth conditions, filtered light, driedin dryer

Normal growth conditions, filtered light, sundried

Sun grown (fruiting from composted kit),dried inside

Normal growth conditions, filtered light, sundried gills down

Normal growth conditions, filtered light, sundried gills up

Normal growth conditions, filtered light,dried in dryer, ground into powder, no sunexposure

Normal growth conditions, filtered light, driedin dryer, ground into powder, 6-8 hours sunexposure

Grown inside, freeze dried, no sun exposure

Grown inside, freeze dried, 6-8 hours sunexposure

Normal growth conditions, filtered light, driedin dryer, no sun exposure

Normal growth conditions, filtered light, driedin dryer, 6-8 hours of sun exposure

Normal growth conditions, filtered light, driedin dryer, no sun exposure

Normal growth conditions, filtered light, driedin dryer 6-8 hours of sun exposure

Vitandin Dcontent

(lU/IOOg)

134

15

110

21,400

1,620

10,900

46,000

137

939

<20

<20

66

2,760

460

31,900

to this author was that Grifo/a frondosa, after beinggrown indoors in filtered light and dried indoors inthe dark, produced 31,900 IU vitamin D upon sunexposure from an ambient level of 460 IU (Table 2).The implications are that vitamin D could be regu-lated by the controlled exposure of dried mushroomsto sunlight. Similarly, overproduction of vitamin Dcould become a health concern if too many vitamin-D enriched mushrooms are consumed.

Mau et al. (1998) also showed that outdoor-grownLentinus edodes contained 5—7 times more vitamin

D than the indoor-grown variety, and that shiitakesgrown in latitudes closer to the equator naturallyhad more vitamin D than those grown in northernregions. In this study, artificial UV exposure from agermicidal lamp for only 1 minute tripled concentra-tions, with a corresponding decrease in ergosterols.However, exposure to UV for 2 hours decreased vita-min D by 12%, because the radiation began breakingdown the vitamin. Perera et al. (2003) determinedthat vitamin D production is most concentrated inthe gills of Z,. edodes, with half as much in the caps,

108 Intemational Joumal of Medicinal Mushrooms

NUTRITIONAL PROPERTIES OF CULINARY-MEDICINAL MUSHROOMS

and a third as much in the stems. Efficiency in con-verting ergosterol to vitamin D was optimized whenmushrooms were at 70% moisture.

Earlier in human history, we got our vitamin Dfrom chemical processes in our skin triggered by ex-posure to sunlight. As our ancestors migrated fromareas near the equator to regions with shorter daysand colder areas where we wore more UV-blockingclothing, our bodies produced less vitamin D. Onewell-known disease from vitamin D deficiency isrickets, which affiicts mosdy children; another effectis decreased bone density. (The FDA dietary labelingguidelines for recommended daily intake (RDI) of vi-tamin D is 400 IUs of vitamin D, equivalent to 10 |ig.Up to 1000 IUs of vitamin D may be helpful for im-mune support). (Raloff, 2004). Vitamin D deficiencymay be a cofactor in the growth of breast, prostate, andcolon cancers and some immune disorders. Mush-rooms, particularly Grifola frondosa, Lentinus edodes,

Ganoderma lucidum, and Trametes versicolor, have beenthe subject of research papers addressing these spe-cific cancers. Logically, all research on animals usingmedicinal mushrooms should take into considerationthe infiuence of the vitamin D inherent within themushrooms being used for the study.

Sunlight drives vitamin D synthesis in fiingi,fish, plankton, reptiles, and mammals. There aretwo distinct pathways for synthesizing vitaminD. In fungi, short-wave ultraviolet light (UVB)converts ergosterols to provitamin D, called D2 orergocalciferol. In parts of the world where vitaminD deficiencies are common, eating fresh shiitakeexposed to sunlight may boost vitamin D levels andmitigate deficiency-related diseases. Another formof vitamin D is vitamin D3, or cholecalciferol, whichis manufactured from 7-dehydrocholesterol in thehuman skin during sun exposure. In summertime,a young Caucasian person's body can make 10,000IUs after 30 minutes of sun exposure.

Our body protects itself from excess vitamin Dproduction through the activities of the parathyroidgland. If too much vitamin D is consumed, then areverse pathway denatures vitamin D. In the process,calcium and phosphorus, whose intake had beenenabled by vitamin D, are now eliminated from thebody. In the event of a severe vitamin D overdose,damaged bone density and blood chemistry could

result as calcium and phosphorus levels plummet,and in extreme cases can be life threatening. TKisbidirectionality of vitamin D regulation points tothe importance of knowing how much to consume,and how much sunlight you need.

Other factors afiFecting the nutritional impactof ingesting mushrooms include heat treatment,particle size, and carriers. Uncooked mushroomsare difficult to digest, and upon tenderizingthrough cooking, the tough skeletal cells soften,rendering a form more readily assimilated by hu-man digestion. Whole mushrooms eaten raw passlargely undigested through the human intestines,imparting little if any nutritional value. Reducingparticle size in combination with thorough cookingincreasing absorbability, although some vitamins,particularly vitamins B, degrade with exposure tohigher temperatures.

As research studies mature, mushrooms move tothe forefront of foods with powerfiil properties use-fiil for nutritionists and doctors as they design dietsfor patients.ihe quality of mushrooms is a reflectionof the environment in which they are grown and howthey are handled subsequent to harvest. Mushroomsfrom polluted lands, whether from Asia, Europe orthe US, concentrate heavy metals, and in some cases(as with cadmium, mercury, cesium) with spectacularefficiency. Other variables, including sunlight expo-sure, drastically influence vitamin D content. Suchvariables mean that a shiitake grown outdoors inAsia may be quantitatively different in its nutri-tional profile than a mushroom grown indoors inthe United States, although they may look the same.Furthermore, dried mushrooms low in vitamin Dcan be used as a source for producing substantialamounts of vitamin D by exposing them to a fewhours of sunlight, a simple technique that could helplessen cancer rates and alleviate osteoporosis-relatedillnesses throughout the world.

ACKNOWLEDGMENTS

The author thanks the employees of Fungi PerfectiResearch Laboratories, particularly Damein Pack,Steve Cividanes,James Gouin,Bulmaro Solano,andDusty Yao, for their assistance.

Volume7, Issues 1&2, 2005 109

p. STAMETS

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Crisan E. V. and Sands A. 1978. Nutritional value. In:The Biology and Cultivation of Edible Mush-rooms. Chang S.T. and Hayes W.A., eds. AcademicPress, New York, pp. 137-168.

Chen S., Kao Y. C, and Laugthon A. 1997. Bindingcharacteristics of aromatase inhibitors and phy-toestrogens to human ziomatase. J Steroid BiocbimMo/Biol, 61,107-115.

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Mau J. L., Chen R R., and Yang J. H. 1998. Ultravioletirradiation increased vitamin D2 content in ediblemushrooms./^^ff Food Cbem 46,5269-5272.

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110 Intemational Journal of Medicinal Mushrooms