Abstract
Quality change of Kimchi packaged with Ny/PE, Ny/CPP (PPtray+Ny/CPP cover), Cryovac BK-1, BK-4, and PET/Al/PE film was observed during storage at $5^{\circ}C$ (97%RH) and $20^{\circ}C$ (76%RH). To evaluate quality change of Kimchi, gas composition of package, pH, acidity, color, growth of lactic acid bacteria, and sensory score were measured periodically. Regarding to gas composition of package, Kimchi packaged with PET/Al/PE showed higher oxygen concentration at the beginning of storage than the others; carbon dioxide concentration was almost 100% at the end of storage. Carbon dioxide concentration of Kimchi packaged with Cryovac BK-1 and BK-4 which has higher gas permeability than the others, was increased to a maximum and then decreased due to permeation of gas during storage; oxygen concentration was increased. Unlike Kimchi packaged with Ny/PE, Ny/CPP, and PET/Al/PE, package swelling was not observed in Kimchi packaged with Cryovac BK-1 and BK-4 during storage. Although pH change was not significant depending on the packaging material, Kimchi packaged with Cryovac BK-1 and BK-4 showed lower pH value and higher acidity than those of the others. Color change of Kimchi was different depending on the packaging material during storage. Difference of the growth of lactic acid bacteria and sensory evaluation were not significant among Kimchi packaged with different packaging material during storage at either temperature. In conclusion, the effect of packaging materials on the quality change of Kimchi was not significant; however, to prevent from swelling of packaged Kimchi which is one of the most serious problem during storage and distribution, might be avoided by using relatively high $CO_2$ permeable film than high gas barrier film.
김치를 Ny/PE, Ny/CPP(PP tray+Ny/CPP cover), Cryovac BK-1, BK-4, PET/Al/PE film으로 포장하여 $5^{\circ}C$ (97%RH), $20^{\circ}C$ (76%RH)에서 저장 중 품질변화를 살펴보았다. 김치의 품질을 평가하기 위하여 포장내 가스조성, pH, 산도, 색도, 젖산균 수, 기호도를 기간별로 측정하였다. 포장내 가스조성은 PET/Al/PE film 포장김치가 저장초기에 산소농도가 높았고, 저장말기에 이산화탄소농도가 거의 100% 수준에 달하였다. Cryovac BK-1, BK-4로 포장된 김치는 발효가 진행되면서 이산화탄소농도가 증가하다가 가스투과성에 의한 이산화탄소의 방출과 외부공기의 유입으로 산소농도는 증가하고 이산화탄소농도는 감소하는 형태를 보였으며 저장말기까지 Ny/PE, Ny/CPP, PET/Al/PE와는 달리 포장의 팽배화 현상은 나타나지 않았다. pH 변화는 포장재질에 따른 차이가 크지 않았으나 Cryovac BK-1, BK-4가 저장중 다른 포장재질에 비하여 약간 낮은 pH를 나타냈으며, 산도는 약간 높았다. 저장중 김치의 색도변화가 포장재질에 따라 달랐으며, 포장재질별 젖산균수, 기호도 변화는 저장온도 모두에서 유의적인 차이가 없는것으로 나타났다. 이상의 결과를 종합하여 본 실험에 사용한 포장재질이 김치의 품질에 미치는 영향은 크게 다르지 않다고 여겨졌고, 저장 및 유통시 문제점인 팽배화현상을 방지하기 위해서는 현재 업체에서 사용하는 기체차단성이 높은 포장재보다는 상대적으로 이산화탄소의 투과도가 높은 포장재의 사용이 바람직하다고 사료된다.
(Korea Food Research Institute)
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