[Introduction] Larix kaempferi (Larch), rich biomass in Hokkaido, is available as an inexpensive medium for mushroom production. We have previously developed a variety of Hypsizygus marmoreus with high ability to utilize larch sawdust without watering, Hm 219 (Marbure 219) with high fruit-body yield and high score of sensory evaluation, was selected. In this study, we investigated the effects of supplements to larch sawdust-based medium on taste components of fruit-bodies of Hm 219. [Materials and methods] The strain of H. marmoreus used in this study was Hm 219, the stock culture of Hokkaido Research Organization Forest Products Research Institute. Each 850 ml plastic bottle containing 540 g of larch sawdust-based substrate, was used for cultivation. Moisture content of each medium was adjusted to 61% based on the fresh weight of the mixture of solid materials. The substrate substituted with 0-40% of supplements (wheat bran, soybean curd residue and soybean shell) for rice bran as a nutrient, were used for cultivation. Cultivation was conducted by the standard procedure reported earlier (Harada et al., 2004). The harvested fruit-bodies were freeze-dried to determine the chemical composition. Soluble sugars, free amino acids and 5’-nucleotides were extracted with hot water from freeze-dried powder. These soluble components were determined by using HPLC. [Results] As a result, fruit-body yields on the substrate substituted with 20% of soybean shell for rice bran as a nutrient, were about 20% higher than those on the substrate with rice bran only. According to the replacement rate of soybean curd residue increasing , morphological quality of fruit-body tended to decline. As major free amino acids in fruit-body, monosodium glutamate-like (MSG-like) components which gave the umami taste, including aspartic acid and glutamic acid, and sweet components including alanine, threonine and serine were detected. As flavor 5’-nucleotides, GMP and IMP were found. In fruit-body of H. marmoreus, with respect to major soluble sugars, mannitol and trehalose were mainly contained. Each taste component content indicated differences among the different supplements to larch sawdust-based medium. The equivalent umami concentration (EUC ) is the concentration of MSG equivalent to the umami intensity of that given by the mixture of MSG and the 5’-nucleotide (Lee, Yu-Ling et al., 2009). The EUC value in a cultivation condition was more 15% higher than that of control condition. [References] Harada, A. et al. (2004) Effects of strain and cultivation medium on the chemical composition of the taste components in fruit-body of Hypsizygus marmoreus. Food Chemistry, 84, 265-270. Lee, Yu-Ling et al. (2009) Composition and non-volatile components of Hypsizygus marmoreus, LWT- Food Science and Technology, 42, 594-598.

Hypsizygus marmoreus, belongs to Tricholomataceae of Agaricales, is widely cultured as the Beech mushroom in Japan. “Haemi” is the first variety developed by intra-specific crossing in Korea. It was improved with hybridization between monokaryotic strain derived from MKACC51987-8 and MKACC51988- 12. The optimum temperature of mycelial growth and fruiting body development were 23-25℃ and 11~17℃, respectively. The color of fruitingbody was grayish brown and cap type was umbrella. It suggest that 'Haemi' is new commercial variety for consumer who concern over healthy and tasty food

The purpose of this study was to develop the best mushroom cultivation conditions and the combination of mushroom culture media in order for mushroom producers and consumers. To reach this target, we first investigated the genetic relationship and developed suitable conditions of mycelial growth in Hypsizygus marmoreus strains. One superior strain of H. marmoreus was selected from 124 strains using bag culture. One hundred and twenty four strains were genetically classified into four main groups using two Universal Rice primers, URP2R and URP17R. The studies on the effects of different temperature (17, 21, 25, 29, 33℃) showed that 25℃ is the best temperature for mycelial growth for almost all strains while at 33℃ most of mycelium stop growth. Finally, ten strains were selected according to the groups identified by their temperature requirements. The length of mycelial growth in PDA, MCM, GPYM, MEA and MYP were longer than those in Czapek Dox. The selected ten strains of H. marmoreus showed heavier dry weight of mycelia at pH 3.0∼7.0 than any other pH. Although it was not show distinct requirement of carbon and nitrogen sources for vegetative growth according to strains, mainly the mycelial growth of the ten selected strains were observed at media including xylan and yeast extract, peptone, tryptone, respectively. Moreover, higher C/N ratio was observed in higher dry weight of mycelia.