Effect of addition amino acids on the mycelial growth and the contents of β-glucan and γ-aminobutyric acid (GABA) in Sparassis latifolia

Sparassis latifolia (formerly S. crispa) is used in food and nutraceuticals or dietary supplements, as rich in flavor compounds and ${\beta}-glucan$. Some previous studies have reported the effects of mushroom on brain function, including its neuroprotective effect. Thus, for this mushroom to be used as an effective nutraceutical for brain function, it would be desirable for it to contain other compounds such as ${\gamma}-aminobutyric$ acid (GABA) in addition to ${\beta}-glucan$. In this study, the enhancement of growth and GABA production in the mycelium of medicinal and edible mushroom S. latifolia was investigated. Amino acids were added externally as the main source of nutrition, and the effects of amino acids were investigated using liquid medium, specifically amino acid-free potato dextrose broth (PDB). The amino acids added were L-glutamic acid (named PDBG medium) and L-ornithine (named PDBO medium). The growth of mycelia was determined to be $0.9{\pm}0.00g/L$, $2.2{\pm}0.16g/L$, and $1.93{\pm}0.34g/L$ PDBG respectively. The GABA content was $21.3{\pm}0.9mg/100g$ in PDB medium, and it in PDBG 1.4% medium, at $115.4{\pm}30.2mg/100g$. However, the PDBO medium was not effective in increasing the GABA content of mycelia. Amino acids had little effect on the ${\beta}-glucan$ content of mycelia. The ${\beta}-glucan$ content was $39.7{\pm}1.4mg/100mg$, $34.4{\pm}0.2mg/100mg$, and $35.2{\pm}9.2mg/100mg$ in PDB, PDBG 1.8% and PDBO 1.4% media, respectively. Addition of glutamic acid and ornithine positively affected the growth of S. latifolia mycelia, and glutamic acid positively affected GABA production; no degradation of GABA was observed with addition of glutamic acid.

아미노산 첨가가 꽃송이버섯 균사체 성장 및 베타글루칸, GABA 함량 변화에 미치는 영향

최근 식용과 약용버섯으로 각광을 받고 있는 꽃송이버섯(Sparassis latifolia 혹은 S. crispa)은 베타-글루칸이 풍부하여 다양한 생리활성을 나타낸다고 알려져 있다. 꽃송이버섯에 다량 포함된 베타-글루칸과 더불어 뇌기능을 증진시킬 수 있는 영양성분이 보강된다면 약용버섯의 기능성이 더욱 증대되어 농가소득 증대와 국민 건강증진에 큰 기여를 할 것으로 판단된다. 본 연구에서는 꽃송이버섯 균사체 배양 시 아미노산을 첨가하였을 시 균사 생장이 촉진됨과 함께 GABA 함량이 증대되었고, ${\beta}-glucan$ 함량에는 유의적인 효과가 없는 것을 확인하였다. 균사의 생장에는 glutamic acid와 ornithine 모두 효과가 있었으나, GABA 함량에 대해서는 glutamic acid의 첨가가 훨씬 효과적임을 확인하였다. 이는 꽃송이버섯 균사체의 GABA-shunt에 glutamic acid가 영향을 미친 것으로 사료된다. 생성된 GABA의 소멸과 다른 화합물의 신규 생성에 대해서는 아직 결과를 도출하지 못하였으므로, 이 부분에 대한 추가 연구가 필요하리라 사료된다.