The influence of chitosan-carboxymethyl celloluse composite and bi-layer film and coatings on flavor quality and volatile profile of Asian sea bass during storage at refrigerator

This study investigated the effects of chitosan-carboxymethyl celloluse (CH-CMC) composite and bilayer coating and film on flavor quality of Asian sea bass (Lates calcarifer) fillets during storage at refrigerator for 16 days. In this experiment, different indexes including: sensory evaluation, trimethylamine nitrogen (TMA-N), total viable counts (TVC), free amino acids (FAAs), volatile organic compounds (VOCs), ATP related compounds, and K value were measured. Main reason for off-flavor of treated samples was mainly attributed to the significant inhibition of bacterial growth after death. The initial total viable count (TVC) (log10 CFU/g) in the all samples of fillet was 1.21 log10 CFU/g. TVC in sea bass fillet became lower than 7 log10 CFU/g for BF (bi-layer film) samples throughout the entire storage. The results of FAAs showed that use CH-CMC reduced the accumulation of bitterness-taste. Treated samples decreased slowly with degradation of inosine- 5′- monophosphate (IMP) resulting higher umami intensity and overall acceptability. Synergistic effects of glutamic acid (Glu) and inosine- 5′- monophosphate (IMP) has inhibitory effects on bitter taste in samples. The VOCs including aldehydes, ketones, alcohols, and hydrocarbons were decreased by the CH-CMC coatings and film. Eight key flavor volatile organic compounds, including 3-methylbutanal, hexanal, E-2-hexanal, ethanol, 1-pentanol, 1-hexanol, 2,3 pentanedion, hydroxyl-2-butanone, were identified in all samples. Generally, these results suggested the advantageous potential for CH-CMC film in retarding formation of fishy odor and taste and improving flavor of Asian sea bass compared with coating during entire the storage time, because of good oxygen barriers properties of film and potential properties to crosslink with flavors in order to enhance functionalities of packaging material.