The effects of ice crystal on water properties and protein stability of large yellow croaker (Pseudosciaena crocea)

This study aimed to investigate the changes in water properties and protein stability of large yellow croaker during freezing. The changes of ice crystals and muscle tissue were assessed using X-ray computed tomography (CT) and light microscopy, respectively. The results of water-holding capacity (WHC), low-field nuclear magnetic resonance, Fourier transform infrared, intrinsic fluorescence, differential scanning calorimetry (DSC), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that compared to the control, freezing treatment resulted in the reduction of WHC and protein stability of the samples. Large ice crystals had a greater effect on muscle water loss, protein secondary and tertiary structure, and protein thermal stability than small ice crystals. The results of Pearson analysis confirmed significant correlation between water properties and protein stability at different ice crystal size. Therefore, these results suggested the beneficial effects of small ice crystals on the water properties and protein stability of croaker, but the effect of low-temperature fracture on the product need to be concerned.