Effect of nano-foamed structure film packaging on the quality of young radish (Raphanus sativus L.) kimchi during storage under supercooled and refrigerated conditions

This study investigated changes in the quality and headspace O2/CO2 concentrations of young radish (Raphanus sativus L.) kimchi (YR-kimchi) packaged using a multilayer (ML) film with or without sachets containing a CO2 absorber and nano-foamed structure (NFS) film, respectively, during storage at −2.2 or 4.0°C. Compared to that in YR-kimchi samples stored at 4.0°C, the total lactic acid bacteria count and titratable acidity of YR-kimchi samples stored at −2.2°C increased rapidly until 21 days of storage, irrespective of the packaging. After 32 days of storage at 4.0°C, the reducing sugar content of young radish kimchi packaged in ML film, ML film with a CO2 absorber sachet, and NFS film decreased by 54.9, 80.7, and 79.9%, respectively, compared to before storage. However, the salinity of YR-kimchi samples packaged with different film types showed negligible differences during storage at −2.2 and 4.0°C. No significant O2 reduction or CO2 accumulation was observed in the headspace of NFS film-packaged young radish kimchi stored at either temperature. Hence, these results indicated that NFS film packaging combined with supercooled (−2.2°C) storage improved the shelf life of YR-kimchi without packaging expansion during storage.