Effects of Low-Molecular-Mass Chitosan Oligosaccharides on the Quality and Microbiota of Silver Carp (Hypophthalmichthys molitrix) during Chilled Storage

This study evaluated the effects of low-molecular-mass chitosan oligosaccharides (COS) on the microbiota and quality of silver carp fillets stored at 4 ℃. The fish fillets were divided randomly into two groups: control and 0.5 g/100 mL COS treatment. To evaluate the preservative effect of COS, sensory scores, total viable count (TVC), total volatile basic nitrogen (TVB-N) content, adenosine triphosphate (ATP)-related compounds and K value were determined and Illumina MiSeq high-throughput sequencing was applied to analyze the microbiota composition. The results indicated that COS altered the composition of microbiota and inhibited the growth of dominant spoilage bacteria (Pseudomonas sp. and Aeromonas sp.). Compared with the control group, COS inhibited the increase in TVC and the production of TVB-N, delayed the degradation of inosine monophosphate (IMP) and hypoxanthine ribonucleotide (HxR), thus retarding the generation of hypoxanthine (Hx). COS improved the quality of silver carp fillets during chilled storage, mainly due to the inhibitory effect on the growth of the dominant spoilage bacteria.