Abstract:The objective of this study was to investigate the effect of transglutaminase (TGase) on gel properties, water distribution, chemical bonding indicators and microstructures of surimi protein-lipids composite gels. The results showed that adding of TGase resulted in a significant (P<0.05) increase in hardness, chewiness, emulsion stability, water holding capacity, indexes of hydrogen bonds and hydrophobic interactions, and non-disulfide covalent bond (ε-(γ-glutamyl) lysine bond) of surimi gels; and the intensity of myosin heavy chain (MHC) band became lighter with the increase of TGase concentrations. Scanning electron microscopy (SEM) images and fractal dimension analysis found that with the increase of TGase concentration from 0% to 0.5%, fractal dimension of surimi protein-lipid composite gel increased from 2.801 to 2.857, which revealed that the degree of surimi protein aggregation become more large, and gel network structure become more dense. These results further explained the mechanism of the effects of TGase on gel properties, emulsion stability and water holding capacity of surimi gels. In general, when the TGase concentration reached 0.4%, the surimi protein-lipid composite gel showed better gel properties.