Quality attributes enhancement of ready-to-eat hairtail fish balls by high-pressure processing

High-pressure processing (HPP) subject to 250 MPa for 5 min or 300, 350 MPa for 3 or 5 min was applied to precooked hairtail (Trichiurus haumela) fish balls for manufacturing ready-to-eat (RTE) surimi products, while effects on quality attributes (microorganism, texture, color, freshness, protein structure, sensory, and water distribution) were investigated. The results indicated that safety and freshness of fish balls treated at 350 MPa for 5 min were significantly improved evidenced by the reduction of total bacterial count (from 726.67 to 7.33 CFU/g) and total volatile basic nitrogen content (from 3.45 to 0.93 mg N/100 g). Additionally, a moderate high-pressure treatment was beneficial for improving textural and sensory properties of hairtail fish balls, including higher springiness, cohesiveness and gel strength. However, a higher pressure (350 MPa) unfolded proteins, and changed the secondary structure of myofibrillar protein, resulting in the decrease of gel strength. Color changes caused by pressurization were within acceptable ranges. Low-field NMR (LF-NMR) results showed a reduction in water mobility and a transfer of immobilized water to bound water for pressure-induced samples. Overall, HPP at 300 MPa for 5 min is suggested for the development of RTE fish balls with favorable quality attributes.