Abstract: To extend the shelf life of hairtail fish balls, this work was undertaken to evaluate the effect of ultra-high pressure (UHP) on the quality preservation of hairtail (Trichiurus haumela) fish balls during refrigerated storage. Hairtail fish balls were treated at 250, 300 or 350 MPa for 5 min. The total bacterial count (TBC), total volatile base nitrogen (TVB-N) content, pH, sensory score, color values, gel strength, and textural parameters of fish balls were measured during refrigerated storage. The results indicated that UHP treatment could significantly decrease the TBC and TVB-N content, and slowed down the increase in pH of fish balls. Furthermore, UHP treatment had no negative effects on the color while maintaining the sensory properties, color values, gel strength, hardness and springiness of fish balls during refrigerated storage. TBC in the control and UHP-treated samples exceeded 105 CFU/g on days 21 and 56, respectively. The sensory score of fish balls in the control group decreased significantly with storage time, off-odor appeared on day 14, and the sensory quality became unacceptable on day 21. There was no significant change in the sensory score of the UHP-treated group within 35 days of storage. The sensory score of the sample treated at 300 MPa for 5 min was still more than 5 on day 49, but became unacceptable on day 56. Overall, the shelf life of fish balls could be extended by approximately 35 days upon UHP treatment at 300 MPa for 5 min, which will provide a basis for the application of UHP to the quality preservation of surimi products.

Key words: ultra-high pressure; hairtail fish balls; preservation; shelf life