Abstract: In order to explore the effect of ultra-high pressure (UHP) on the bacterial community structure and quality of stinky mandarin fish, the samples were treated at atmospheric pressure (control), 300 or 500 MPa for 10 min, and the change in the bacterial community structure after UHP treatment was detected by high-throughput sequencing. Besides, the changes in the color, water-holding capacity, shrinkage rate, sensory attributes, microstructure and infrared spectrum were evaluated. The results showed that UHP treatment had a significant effect on the bacterial community composition, significantly reducing the species diversity. The predominant genera were Vagococcus and Psychrobacter in stinky mandarin fish before and after UHP treatment. Compared with the control group, UHP treatment showed higher whiteness and lower water-holding capacity and shrinkage rate, and imparted relatively better sensory quality to treated samples at 300 MPa. The scanning electron micrographs revealed that the microstructure of muscle tissue became blurred and the structure of muscle fibers became more compacted and disordered after UHP treatment. The Fourier transform infrared spectrum showed that the treatment changed the secondary structure of myofibrillar protein from stinky mandarin fish, decreasing the proportions of α-helix and β-turn and increasing the proportions of random coil and β-sheet. Consequently, treatment at 300 MPa for 10 min imparts better texture characteristics and sensory quality to stinky mandarin fish.

Key words: stinky mandarin fish; ultra-high pressure; high-throughput sequencing; bacterial community structure; quality