Effects of chitosan and sodium alginate active coatings containing ε-polysine on qualities of cultured pufferfish (Takifugu obscurus) during cold storage.

The present study evaluated the effects of chitosan (CH) and sodium alginate (SA) bioactive coatings containing 0.1, 0.2 and 0.3% ε-polylysine (ε-PL) combined with high CO2 modified atmosphere packaging conditions (MAP, 60% CO2/5% O2/35% N2) on the quality of cultured pufferfish (Takifugu obscurus) at 4 °C for 18 days. Results showed that CH-SA coatings containing ε-PL and high CO2 MAP treatments could significantly lower total viable count (TVC), Pseudomonas spp., H2S-producing bacteria and lactic acid bacteria counts (LAB), and reduce the productions of off-flavor compounds including total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and ATP-related compounds. Volatile compounds were identified and quantified by SPME gas chromatography-mass spectrometer (SPME-GC/MS) for pufferfish during cold storage and the bioactive coating treated pufferfish significantly lowered the relative content of fishy flavor compounds, such as 1-octen-3-ol, hexanal, (E)-2-octenal, octanal and 2,3-butanedione. Further, CH-SA coatings containing ε-PL and high CO2 MAP treatments could more efficiently retard the water migration by magnetic resonance imaging (MRI) results, and maintained the quality of pufferfish during storage at 4 °C according to organoleptic evaluation results.