Regulating surimi particle size promotes ice-crystal alignment and anisotropic lamellar structuring in vacuum-compressed surimi-based products: Protein conformation and microstructural insights

This study aims to investigate the influence of surimi particle size on anisotropic lamellar structure formation in restructured fish products and the mechanisms underlying the evolution of associated microstructures and protein conformations. Silver carp surimi with varying disruption levels was prepared by controlling chopping time, followed by vacuum processing, compressing, freezing, and frying to obtain the final products. Moderate chopping (4 min) produced a relatively uniform matrix with intermediate particle size and protein solubilization, which tended to promote the formation of well-oriented ice crystals during freezing and resulted in relatively distinct lamellar structures after heating. These samples exhibited a maximum measured anisotropy index of 2.64, moderate hardness and chewiness, improved water distribution, and relatively favorable sensory characteristics. Moreover, moderate chopping induced partial protein unfolding, accompanied by increased exposure of free sulfhydryl and hydrophobic groups and interconversion between α-helix and β-sheet structures, thereby establishing a balanced protein continuous phase.