Abstract:The paper aimed to explore the effects of different modified methods on the structure and function characteristics of porcine liver protein（PLP）.PLP was modified by ultrasonic treatment，pH-shifting treatment，and ultrasound-assisted pH-shifting treatment.The solubility，surface hydrophobicity，emulsification property，sulfhydryl content，particle size，Zeta potential，primary and tertiary structure，and their changes in the modified PLP were measured.The results showed that the particle size of PLP decreased and the absolute value of solubility and potential increased after ultrasonic treatment.When the PLP solution was adjusted to pH3 and then returned to neutral（pH3-7），the particle size of PLP increased，and the solubility and absolute potential decreased.After ultrasound-assisted pH-shifting treatment（pH3U-7），the particle size of protein decreased，and the solubility and absolute potential increased，but the effect was not obvious.When the PLP solution was adjusted to pH9，then returned to neutral（pH9-7），and combined with ultrasonic treatment（pH9U-7），the particle size of protein decreased，and the solubility and absolute potential increased.Acid/base pH-shifting and ultrasound-assisted treatment reduced the fluorescence intensity and active sulfhydryl content of PLP.The electrophoresis results showed that pH3-7 may lead to the disulfide bond aggregation of PLP，pH9-7 had no obvious effect on the electrophoresis strip，and the addition of ultrasound did not further change the electrophoresis strip.Compared with the control group，ultrasonic treatment，the pH9-7 and pH9U-7 groups improved the emulsifying activity and lotion stability of PLP，while the pH3-7 and pH3U-7 groups reduced the emulsifying activity and lotion stability.