아열대 마(Dioscorea alata)의 저장중 부패 억제를 위한 큐어링 효과

Effect of Curing Conditions on Inhibition of Tuber Rot in Subtropical Yam (Dioscorea alata) during Storage

국내에서 생산되는 아열대 마의 저장성을 향상 시키고자저장기간 동안 발생되는 주요 병원균을 분리동정하여 병원성을 확인하고, 큐어링 처리 조건별로 부패억제 효과를 조사하였다. 아열대 마 저장중 부패를 일으키는 주요 병원균은 Penicillium sclerotigenum와 Penicillium polonicum 으로 확인되었고 P. sclerotigenum이 좀더 병원성이 강하였다. 수확도중 절단된 부위는 큐어링 하기전 반드시 매끈하게 잘라야만 정상적인 유상조직층이 형성되었다. 괴근 절단면을 상대습도 95%에서 3일간 23℃, 28℃ 그리고 33℃로 큐어링 처리하여 유상조직층을 관찰한 결과, 23℃ 처리구는 괴근육과 표피층의 색농도가 비슷하여 확인이 어려운반면, 28℃ 이상 처리구는 뚜렷하게 관찰되었다. 0.5 mm 이상의 유상조직 형성율도 28℃ 처리에서 93%, 33℃처리에서96%로 양호하였으나 23℃처리구에서는 52%로 낮게 나타났다. 상온에서 바람이나 햇볕을 이용하는 관행적인 큐어링처리구는 유상조직층 형성이 미미하였다. 저장고안의 상대습도에 따른 병원균의 감염은 습도가 40%와 60%로 유지되었을 경우 감염비율이 낮았고 큐어링 처리간에도 차이가없었다. 저장고내 습도가 80%인 경우 모든 처리구에서 균이급격히 증식하였다. 저장온도 16℃에서 상대습도 60%를 유지하여 180일 후 처리별로 부패율을 조사한 결과, 절단된괴근을 햇볕이나 바람에 의해 큐어링된 관행적인 처리구는43%였으나, 28℃ 이상에서 큐어링하여 유상조직층이 형성된 괴근은 18% 이하로 나타났다. 건전한 괴근도 관행처리구에서 25%의 부패율을 보인 반면 28℃ 이상에서 큐어링된괴근은 10% 이하로 나타났다. 중량감소율도 관행처리구에비하여 강제 처리구가 중량이 1~6%정도 덜 감소하였다.

In order to improve storability of subtropical yam produced in South Korea, the major pathogens found during the storage were isolated and identified of the pathogenicity, and rot inhibition effect was studied based on the curing treatment condition. Penicillium sclerotigenum and Penicillium polonicum were identified as major pathogens causing rot in subtropical yam during storage, and P. sclerotigenum had stronger pathogenicity. Only the cut surface which has been made during a harvest and has been made smooth before curing generated a normal callus layer. The cut surface of tuberous root was cured in 95% of relativity humidity for three days at 23℃, and cured at 28℃ and 33℃. The observation of callus layer showed that the 23℃ treatment group had similar color saturation between tuberous root and pellicle, while the groups treated above 28℃ showed clear distinction. The generation rate of callus 0.5mm or bigger was 93 percent at 28℃treatment, 96% at 33℃ treatment, but was 52% at 23℃ treatment. The conventional curing treatment group that used wind or sunlight at room temperature created little callus layer. The infection rate of pathogens according to the relative humidity inside the storage room was low at 40% and 60% of humidity, and the curing treatment period did not make a difference. When the humidity inside the storage room was 80%, all treatment groups rapidly increased the fungal pathogens. The rotten rate of each treatment was studied after 180 days during which the storage temperature was maintained at 16℃ and relative humidity 60%. While the rotten rate of tuberous root that has been cut in conventional curing treatment based on solar and wind was 43%, the one cured at over 28℃ and created the callus layer was less than 18%. While even a healthy tuberous root showed 25% of rotten rate in the traditional treatment group, the one cured at over 28℃ was less than 10%. The weight loss was 1-6% lower in the forced treatment group than in the conventional treatment group.