Comparison of Leaf Color and Storability of Mixed Baby Leaf Vegetables according to the Mixing Ratios of Red Romaine lettuces (Lactuca sativa), Peucedanum japoincum, and Ligularia stenocephala during MA Storage
본 연구는 산채을 활용한 어린잎 혼합 포장 상품의 개발하기 위해 기존 어린잎채소에 많이 사용되고 있는 어린잎 적로메인 상추(Lactuca sativa ‘Red romaine’)에 어린잎 산채로 갯기름 나물(Peucedanum japoincum Thunberg)과 곤달비(Ligularia stenocephala)을 혼합하여 적합한 비율을 알아보고자 수행하 였다. 적로메인과 산채의 혼합비율은 적로메인0 : 갯기름5 : 곤 달비5(R0:P5:L5), 적로메인3.3 : 갯기름3.3 : 곤달비3.3(R3.3: P3.3:L3.3), 적로메인5 : 갯기름2.5 : 곤달비2.5(R5:P2.5:L2.5), 적로메인8 : 갯기름1 : 곤달비1(R8:P1:L1), 적로메인10 : 갯기름0 : 곤달비0(R10:P0:L0)으로 처리하였다. 모든 처리구는 OTR(Oxygen transmission rate) 10,000cc·m -2 ·day -1 ·atm -1 필름으로 포장하여 2°C/85%RH 저온고에서 27일간 저장하며 생체중 감소율, 포장내 이산화탄소/산소/에틸렌 농도, 외관, 엽록소 함량, 색도를 조사하였다. 생체중은 R8:P1:L1 처리구가 0.4% 미만의 가장 낮은 감소율을 보였고, 이를 제외한 나머지 처리구들은 0.5% 내외의 수치를 나타내었으나 통계적 유의성은 없었다. 포장내 산소와 이산화탄소 농도는 작물의 호흡률에 영향을 받았는데, 호흡률이 낮았던 상추의 혼합 비율이 높아질수록 포장내 산소농도가 높았고, 이산화탄소 농도는 낮았다. 산소농도는 15일이후 크게 감소하였으나, 16%이상은 유지되었고, 이와 반대로 이산화탄소 농도의 경우 15일까지 1-4%로 유지되다가 서서히 증가하여 27일차에 는 2-5%로 증가하였다. 에틸렌 농도는 저장 종료일까지 3-6μL·L -1 내외의 농도를 유지하였다. 저장 종료일의 외관상 품질은 모든 처리구가 상품성 한계점인 3점에 다소 못 미치는 정도를 보였다. 엽록소 함량(SPAD)은 처리구간 통계적 유의성은 없었으나, 적로메인과 곤달비의 경우 R8:P1:L1 처리구에서, 갯기름나물은 R5:P2.5:L2.5과 R8:P1:L1처리구에서 가장 적게 감소하였다. Heat map으로 비교한 3가지 작물의 엽색(L * , a * , b * , chroma)은 R5:P2.5:L2.5와 R8:P1:L1 처리구에서 저장 후 가장 변화가 적었다. 이중 R8:P1:L1 처리구는 엽록 소 함량도 가장 높게 유지되었으며 포장내 에틸렌 농도도 2번째로 낮았고 이산화탄소 농도는 2-3% 수준을 유지하였다. 따라서 적로메인 8, 곤달비 1, 갯기름 1(R8:P1:L1)의 혼합한 비율이 이 3가지 작물의 어린잎 혼합 포장에 가장 적합한 것으로 판단된다.
This study attempted to find a way to maintain the quality of mixing baby wild leaf vegetables with existing baby leaf vegetables in various ratios. The crops for mixing baby leaf vegetables were Peucedanum japoincum Thunberg and Ligularia stenocephala, as wild vegetables, and red romaine, which is widely used in young leafy vegetables. The mixing ratio of red romaine and wild vegetables was red romaine 0: mantilla oil 5: L. stenocephala ratio 5 (R0: P5: L5), red romaine 3.3: P. japoincum 3.3: L. stenocephala ratio 3.3 (R3.3: P3.3: L3.3), red romaine 5: P. japoincum 2.5: L. stenocephala 2.5 (R5: P2.5: L2.5), red romaine 8: P. japoincum 1: L. stenocephala 1 (R8: P1: L1), red romaine 10: P. japoincum 0: L. stenocephala 0 (R10: P0: L0). All treatments were packaged in OTR (oxygen transmittance) 10,000 cc m -2 ·day -1 ·atm -1 film and stored for 27 days at 2°C/85% RH conditions. Fresh weight, carbon dioxide, oxygen, and ethylene concentrations of the baby leaf packages were examined approximately every 3 days, and visual quality, chlorophyll content, and chromaticity were examined on the 27th day of storage. The oxygen and carbon dioxide concentration in the packages were affected by the respiration rate of the crop. As the mixing ratio of lettuce, which had a low respiration rate, increased, the oxygen concentration in the packages was higher and the carbon dioxide concentration was lower. Oxygen concentration decreased significantly after 15 days, but was remained above 16%, and on the contrary, carbon dioxide concentration was kept at 1-4% until the 15th, and then gradually increased to 2-5% on the 27th day. The concentration of ethylene was maintained at 3-6 μL·L -1 until the end of storage (27th day). Visual quality score measured at the end of storage was slightly less than 3.0, which is the limit of marketability of all treatments. Although there was no significant difference, the chlorophyll content (SPAD) of red romaine and P. japoincum were most similar with an initial value in R8:P1:1 treatment, and L. stenocephala was higher value in R8:P1:L1 and R5:P2.5:L2.5 treatments at the end of storage. The leaf color (L*, a*, b*, chroma) of the three crops at end of storage compared with the heat map showed the least change in the R5:P2.5:L2.5 and R8:P1:L1 treatments at the end of storage. Among them, R8:P1:L1 treatment maintained the highest chlorophyll content, the second lowest ethylene concentration, and adequate carbon dioxide concentration of 2-3%. Therefore, it is judged that the mixed ratio of red romaine 8: P. japoincum 1: L. stenocephala 1 (R8: P1: L1) is most suitable for the mixed package of baby leaf vegetables of these three crops.