Novel insights into induced low-salt Mandarin fish (Siniperca chuatsi) surimi gel with transglutaminase and microwave heating

The present work examined water bath (WB) heating with microwave heating (WM) under different levels of transglutaminase (TGase) additions in a low-salt Mandarin fish surimi to obtain excellent gel properties. The breaking force was gradually enhanced with increased TGase additions (0.0 - 0.8 U/g), while WM with 0.8 U/g TGase produced the maximum gel strength. In the texture analysis, WM depicted a reduced hardness and an increased springiness at the corresponding TGase additions than that of WB. In low-field nuclear magnetic resonance spectroscopy (LF-NMR) studies, TGase reduced water protons’ relaxation times to different extents, while WM increased their water-binding abilities, especially at 0.8 U/g. Fourier transform infrared spectroscopy (FT-IR) revealed that the relative contents of the secondary structures did not apparently change at 0.2 - 1.0 U/g. Therefore, using WM and adding 0.8 U/g TGase improved the gel quality of low-salt Mandarin fish surimi gel, providing a new strategy for preparing healthy surimi products.