• The Korean Journal of Mycology
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• v.47 no.4
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• pp.337-346
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• 2019

To develop a new antidementia acetycholinesterase (AChE) inhibitor from edible mushrooms, the inhibitory effects on AChE of water and ethanol extracts from various edible mushrooms were measured. Among the tested compounds, 70% ethanol extracts from Tremella fuciformis showed the highest AChE inhibitory activity, at 25.3% (IC₅₀: 9.9 mg). Water extracts from the fruiting body of Pleurotus ostreatus (Heuktari) showed AChE inhibitory activity of 20.2% (IC₅₀: 12.4 mg). However, the yield (40.8%) from Pleurotus ostreatus (Heuktari) was higher than that from Tremella fuciformis (5.0%). Therefore, we selected Pleurotus ostreatus (Heuktari) as the most promising candidate for a mushroom containing anti-dementia AChE inhibitors. The AChE inhibitor from Pleurotus ostreatus (Heuktari) was optimally extracted when its fruiting body was treated with water for 6 h at 30℃. The anti-dementia effects of the partially purified AChE inhibitor from Pleurotus ostreatus (Heuktari) were observed in PC12 nerve cells.

• Journal of Mushroom
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• v.14 no.4
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• pp.174-178
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• 2016

Simple sequence repeats (SSR), also referred to "microsatellites" consist of tandemly repeated short DNA sequence motifs and have been applied in various marker-based studies. SSRs were isolated and characterized from 'Heuktari' and 'Miso', which are major oyster mushroom cultivars in Korea, by genome sequencing and bioinformatic analysis. The genome sizes of 'Heuktari' and 'Miso' were estimated to be 40.8 and 40.3 Mb, respectively, which are larger than those of other P. ostreatus species (PC9 and PC10) and smaller than those of P. eryngii (KNR2312P5). In total, 949 and 968 SSRs were found in the 'Heuktari' and 'Miso' genomes, respectively. Comparative analysis of five mushrooms including P. ostreatus var. florida (PC9 and PC15) and P. eryngii revealed that the number of SSRs in 'Heuktari' and 'Miso' were the highest among them. All mushrooms studied showed similar SSR distribution patterns. Tri-, hexa-, and octanucleotide motifs accounted for the top three fractions of all SSRs.

• Korean Journal of Organic Agriculture
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• v.24 no.1
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• pp.61-71
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• 2016

This study was carried out to investigate antimicrobial activities of water extracted Pleurotus ostreatus var Heuktari (PO), and their application to F. fujikuroi Nirenberg growth inhibition material. Various organic solvents (chloroform, hexane, ethyl acetate, ethanol) were tested to investigate the antimicrobial activities of Pleurotus ostreatus var Heuktari against F. fujikuroi Nirenberg. Chloroform, hexane, ethyl acetate and hot water extracts had no antimicrobial activities, but butanol extract showed 2.5% strong activities in order of F. fujikuroi Nirenberg disk diffusion test. Then we observe Antifungal activity using green house. Bed soil and mushroom extract mixed at 10%, 7.5%, 5%, 2.5%, 1% total bed soil mass. Screening of Antifungal activity was tested two periode 18day and 25day. The Antifungal activity rate of each period and extract density was 7.5% mixed bedsoil has investigated 80% Antifungal activity rate. The result indicates that the Pleurotus ostreatus var Heuktari extract using F. fujikuroi Nirenberg registance, which shows the development of organic agriculture seed disinfectant.

• Journal of Mushroom
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• v.18 no.4
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• pp.317-322
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• 2020

This experiment was conducted to solve the failure of fruiting body production in the bottle cultivation of the oyster mushroom cultivar 'Heuktari'. The effects of incubation temperature on primordium formation and fruiting body yield of the oyster mushroom cultivar 'Heuktari' were investigated. The proper temperature for mycelium growth of 'Heuktari' on potato dextrose agar (PDA) medium is 23-26℃. The mycelial growth of 'Heuktari' was faster than that of Chunchu 2ho. During mycelial culture in sawdust medium, the temperature of the medium in the bottle initially increased, reached the highest point in the middle of the culture, and then decreased. The higher the set temperature, the shorter the incubation period. When the incubation temperatures were 20℃ and 24℃, respectively, the undeveloped primordium formation rates were low (1.8% and 4.2%, respectively). However, the rate of undeveloped primordium formation increased, and the yield decreased at incubation temperatures of 16℃ and 28℃. Mushroom farms that set incubation temperatures to 18℃ and maintained the medium temperature at less than 28℃ showed undeveloped primordium formation rates ranging between 0.3-0.8%. The rate of undeveloped primordium formation increased and the yield decreased in the farms with high incubation temperatures (above 28℃). We found that in order to reduce undeveloped primordium formation, the air inside the incubation room should be circulated continuously so that the temperature of the medium does not rise above 28℃, and dense incubation conditions should be avoided.

• Journal of Mushroom
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• v.13 no.1
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• pp.74-78
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• 2015

The 'Heuktari', a new mid-high temperature adaptable variety of oyster mushroom for the bottle culture, was bred by mating with monokaryons isolated from 'P11056' and 'MT07156'. The optimum temperature for the mycelial growth was $23{\sim}26^{\circ}C$ on PDA medium and that for the primordia formation and the growth of fruiting body of 'Heuktari' was $18{\sim}19^{\circ}C$ on sawdust substrate. In case of bottle cultivation, the period of mycelial growth was required about 30 days. In addition, the period of primordia formation and growth of fruiting body was 4 days and 5 days, respectively. In the characteristics of fruiting body, shape and color of pilei were round type and dark grayish brown, stipe color was white color and stipe shape was short and thick. The yield of fruiting bodies was 180 g/900 ml bottle which was 15% higher than that of Suhan-1ho. The gumminess and brittleness of stipe tissue were 110% and 140% stronger than those of Suhan-1ho, respectively.

• Journal of Mushroom
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• v.19 no.4
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• pp.329-335
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• 2021

This experiment was conducted to investigate the changes in freshness parameters and determine the optimal UV-B irradiation conditions for each storage period for Heuktari, an oyster mushroom cultivar, grown under LED lightNo significant changes were observed in the CO₂ and O₂ content until day 12 of storage; however, after day 15, the CO₂/O₂ ratios were higher in the UV-treated groups than in the untreated groups. No color difference was observed between the UV-treated and untreated groups. In all UV-treated groups, hardness decreased over time; however, the group irradiated for 15 minutes showed higher hardness values than those of the untreated group. The UV-irradiated group showed higher ergosterol content than did the untreated group, and scanning electron microscopy revealed that mushroom cell wall destruction increased with increased UV treatment time. Overall, these findings confirmed that UV-B irradiation increased the ergosterol content of Heuktari but decreased its freshness and negatively impacted other storage characteristics.

• Journal of Mushroom
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• v.21 no.3
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• pp.173-178
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• 2023

In this study, the characteristics and taste components of six different oyster mushroom cultivars (Gonji-7ho, Santari, Baekseon, Chunchu, Suhan, and Heuktari) were analyzed and compared. The Heuktari mushroom pileus had the lowest brightness index (32.8) and remained dark (brightness index: 30.5) even after blanching. The moisture content of the mushrooms was approximately 90%. The salinity and sugar contents were highest in Heuktari (5.7% and 7.1%, respectively). Gonji -7ho had the highest contraction rates, with a length contraction rate of 16.4% and thickness contraction rate of 23.9%. The total amino acid content was highest in Heuktari (537.8 mg/100 g), but the glutamine content contributing to umami taste was highest in Santari (59.4 mg/100 g) and the aspartic acid content was highest in Baekseon (33.1 mg/100 g). Among the 5?-nucleotide components, guanosine monophosphate, which enhances umami taste, was highest in Baekseon (0.7 mg/g). Baekseon was also calculated to have the highest umami taste concentration based on amino acid and nucleic acid contents (12.7 g/100 g). The results of this study serve as valuable basic data on the physicochemical characteristics of oyster mushroom cultivars grown in Korea.

• Journal of Mushroom
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• v.14 no.4
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• pp.202-206
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• 2016

Oyster mushrooms are widely cultivated and consumed in Korea. P. ostreatus 'Suhan(ASI 2504)' is an ideal cultivar for mushroom farmers due to its dark pileus and thick stipe; however, as it is very sensitive to environmental conditions, an alternative cultivar is required. To develop a new cultivar, parental strains 'Suhan(ASI 2504)' and 'ASI 0665 (Heuktari)' were selected from various collected strains according to morphological characteristics. P. ostreatus 'Soltari' was developed by DiMon crossing between the dikaryotic strain 'Suhan' and the monokaryotic strain derived from 'Heuktari'. Thirty-eight of the 100 crossed strains were selected following analysis of mitochondrial genetic characteristics, and 'Soltari' was ultimately selected by continuous cultivation tests. The mitochondrial DNA profile of 'Soltari' was found to be the same as that of 'Heuktari, and a nuclear DNA profile of 'Soltari' was similar as those of the parental strains, 'Suhan' and 'Heuktari.' 'Soltari' mycelium grows adequately in moderate to high temperatures of $12-20^{\circ}C$, although its optimum temperature was found to be $30^{\circ}C$. Fruiting body production per 1.1-L cultivation bottle was approximately 158.8 g. Its stipe length and thickness were comparable to those of diameter and thickness were somewhat lower (42.72 vs. 51.33 mm and 18.18 vs. 22.46 mm, respectively). 'Soltari' was found to be more resistant to high $CO_2$ atmosphere than 'Suhan', and the color of the pileus of 'Soltari' was dark gray at high temperature. Therefore, it is suggested that this new cultivar 'Soltari' is a good alternative cultivar and will contribute to energy saving in oyster mushroom farms.

• Journal of Mushroom
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• v.20 no.4
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• pp.270-273
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• 2022

The present study investigated the optimum additive ratio of wheat straw pellet as a substitute for beet pulp during oyster mushroom cultivation. The chemical properties across treatments were pH of 4.8-5.5, total carbon content of 45.9-46.5%, total nitrogen content of 1.5-1.7%, and carbon-to-nitrogen ratio of 27.8-31.0. Mycelial growth was the fastest in a medium containing 20% wheat straw pellet (at 88.2 mm in 'Heuktari' and 70.3-79.6 mm in 'Suhan-1Ho'); however, there were no significant differences in mycelial density among the treatments. The characteristics of fruiting bodies by variety were as follows. In 'Heuktari', the valid stipe number per bottle (1,100 cc) was 22.5 and yield was 177.1 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls. In 'Suhan-1Ho', the valid stipe number per bottle (1,100 cc) was 14.0 and yield was 151.2 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls.

• Journal of Mushroom
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• v.20 no.3
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• pp.168-172
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• 2022

This study was conducted to investigate the optimum supplementation ratio when replacing cotton seed meal with rapeseed meal for cultivating oyster mushrooms. The chemical properties among the treatments were pH 4.5~4.7, total carbon content was 46.3~46.5%, total nitrogen content was 1.6~1.7%, and carbon-nitrogen ratio was 27.0~27.8. These did not differ significantly from the control. Mycelial growth was 85.1 mm (Heuktari), and 72.8 mm (Suhan-1Ho) in medium containing 5% rapeseed meal, with no significant difference in mycelial density between cultivars. Fruiting body characteristics are as follows: In 'Heuktari', the color of the pileus was darker than control with an L value of 32.5, and pileus thickness and diameter were 3.2 mm and 27.6 mm, respectively. Stipe length and diameter were 86.0 mm and 9.1 mm, respectively. Valid stipe number per bottle (1,100 cc) was 25.9, and a yield of 189.7 g/1,100 cc was recorded in mixed medium containing 5% rapeseed meal (higher than control). In mixed medium containing 10% rapeseed meal, the yield was 184.5 g/1,100 cc (comparable to control). In 'Suhan-1Ho', supplemented with 5% rapeseed meal, pileus color was darker than control color, with an L value of 28.8. Pileus thickness was 4.5 mm. Stipe diameter was 12.3 mm (higher than control), and yield was 145.5 g/1,100 cc (comparable to control).