Abstract: In this work, the effect of transglutaminase (TG) on the quality of mandarin fish (Siniperca chuatsi) surimi gel (MFSG) was determined by measuring salinity, water-holding capacity (WHC), whiteness, texture, sensory evaluation, protein secondary structure and microstructure as well as using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results showed that TG could improve the whiteness of MFSG. As compared with the control group, MFSG with TG presented significantly increased gumminess, chewiness and resilience (P < 0.05). Gel hardness increased significantly with increased TG addition (P < 0.05), and WHC reached its maximum value at an addition level of 0.6 U/g. SDS-PAGE showed the main protein bands gradually weakened with increase of TG concentration. By scanning electron microscope (SEM), it was observed that after addition of TG, MFSG generated a denser network structure. Therefore, TG could greatly improve the quality of MFSG, especially at 0.4 and 0.6 U/g. These results may provide a theoretical basis for improving the quality of MFSG.

Key words: mandarin fish surimi; transglutaminase; texture properties; gel quality