Proximate Compositions and Vitamin D2 Contents of the Cultivated Mushrooms of Tricholornataceae

Abstract

Among the cultivated mushrooms of Tricholomataceae, Enokitake (Flammulinavelutipes), Hatakeshimeji (Lyophyllum decastes) and Nioushimeji (Tricholoma giganteurn), the proximate compositions, minerals, vitamins, dietary fiber, polysaccharides, fatty acids, and ergosterol contents were analyzed.Mushrooms are considered to be a good source of vitamin D2; therefore the determinations of vitamin D2 and studies of the effects of solar irradiation on the amounts of vitamin D2 and the quality of the mushrooms were conducted. The results were as follows.The proximate compositions, minerals and dietary fiber of these mushrooms closely agreed with previous reports. However, the vitamin B1 and B2 contents were slightly lower. The result of the vitamin D2 analysis showed that fresh mushrooms were found not to contain vitamin D2that differed from the Standard Table of Food Composition in Japan-VITAMIND-and the Standard Table of Food Composition in Japan, Fifth Revised Edition-shinkishokuhinhen-. However a remarkable production of vitamin D2 was observed due to solar radiation. The maximum values of vitamin D2 were observed in mushrooms irradiated for 1hour. This amount of solar radiation had no bad effects on the mushroom's quality.These mushrooms contained high levels of alkali acid-soluble polysaccharides, followed by formic acid-soluble polysaccharides and then hot alkali-soluble polysaccharides. The alkali-soluble acid-insoluble polysaccharides and acetic acid-solublepolysaccharides were found at low levels.Prosky modification I showed the lowest value followed by the chitin corrected method. Prosky modification II resulted in the highest values. These three methods gave significantly different values.In Enokitake, the contents of the linolenic and linoleic acids were specifically high. Hatakeshimeji and Nioushimeji contained high levels of linoleic and palmitic acids. The ergosterol contents were 216, 124 and 258mg/100g dry matter in Enokitake, Hatakeshimeji and Nioushimeji respectively.