Physicochemical and microbiological characteristics of surimi seafood under thermal and e-beam processing

Effects of thermal and electron beam (e-beam) processing on microbial inactivation and physichochemical properties of surimi and surimi seafood were investigated. Thermal-death-time (TDT) concept was used to model Staphylococcus aureus inactivation by heat and e-beam. Gurney-Lurie charts were used to estimate temperature during thermal processing of surimi seafood. Dose mapping technique was used to estimate dose absorbed by surmi seafood during e-beam processing. The dose absorbed increased up to 2 cm and then it gradually decreased, reaching a minimum at 5 cm depth of surimi seafood. It was determined that one and two-sided e-beam can efficiently penetrate 3.3 and 8.2 cm of surimi seafood, respectively. The D-value for thermally inactivated S. aureus was 0.65, 1.53, 6.52, 49.83, and 971.54 s, at 95, 85, 75, 65, and 55°C, respectively. The D-value for S. aureus inactivated with e-beam was 0.34 kGy. The z-value for thermally inactivated S. aureus between 55–95°C was not linear. Thermal processing degraded texture and color of surimi seafood. E-beam enhanced firmness and decreased the b* value of surimi seafood. Myosin heavy chain (MHC) degraded proportionally to the e-beam dose. Actin was not affected by e-beam except treatment at 25 kGy. Hydrophobic interactions and disulfide bonds were formed in raw Alaska pollock surimi when treated with e-beam.