Abstract:In this study，myofibrillar protein（MP）was used as the research object. The regulation mechanisms of ultrasound-assisted glutamine transaminase（TG）on the conformation and gel properties of MP were analyzed by circular dichroism，fluorescence spectroscopy，electrophoresis，rheology，and scanning electron microscopy. The results indicated that as the ultrasound time prolonged，the α-helix content，the fluorescence intensity and solubility of endogenous tryptophane of MP decreased significantly，and the crosslinking aggregation of the protein was aggravated，which further led to the decrease in the storage modulus（G′）and the hardness of gel. However，the cooking loss was improved（decreased by 34.8%）. TG and ultrasound-assisted TG treatment reduced the solubility of MP but significantly improved the gel-forming ability and the water-holding capacity. Ultrasoundassisted TG treatment significantly increased the α-helix content of MP and reduced the cooking loss by 50.5%，which was favorable to the formation of a denser and more uniform three-dimensional gel network structure. In summary，ultrasound-assisted TG of 100 W for 20 s could significantly enhance the texture characteristics and water-holding capacity of MP.