Effect of active ice nucleation bacteria on freezing and the properties of surimi during frozen storage

Abstract

The effects of active ice nucleation bacteria (INB, Pseudomonas syringae) on freezing, ice crystal formation, and aggregation, and oxidation of surimi from Talang queenfish (Scomberoides commersonnianus) during frozen storage were investigated. The shortest freezing time (225 min) and the highest onset temperature (−7.0 °C), as determined by differential scanning calorimetry (DSC), was found for surimi with 106 colony-forming units of INB mL−1 100−1 g (INB c1). The surimi showed better structure with the lowest inter-fiber space along with finer and more homogenous myofibrillar proteins (MP) surface morphology and a lower root-mean-square (Rq, 142 nm) from atomic force microscopy (AFM) after 90 days of storage at −18 °C, which was associated with the highest ζ-potential (−9.0 mV) than the control (−6.2 mV) which reflected a lowered MP aggregation behavior. Compared to the control, protein carbonyls in surimi with INB c1 decreased significantly, while showing a lower decrease in total sulfhydryl groups (P < 0.05). Overall, INB c1shortened the freezing time and increased freezing rate, while decreasing oxidation and aggregation of surimi proteins.