Abstract:To enhance the application potential of soybean lipophilic protein （SLP） in the field of aerated foods，this study used SLP and pectin （PC） as raw materials to investigate the effects of different mixing ratios of SLP and PC on the physicochemical properties，structural characteristics and foaming performance of the composite system. The microscopic morphology，average particle size，Zeta potential，intrinsic fluorescence spectroscopy，Fourier transform infrared spectroscopy（FTIR），surface hydrophobicity，interfacial tension and foaming properties of the SLP-PC composites were analyzed，and the microstructure of the foams was observed.The results showed that compared with pure SLP，when the mass ratio of SLP to PC was 4∶1，the foaming capacity of the composite was significantly increased to 125%，and the foaming stability was improved to 43.6%.Structural analysis indicated that PC bound to SLP through hydrogen bonding，electrostatic and hydrophobic interactions，which induced protein unfolding，triggered the transition of the protein secondary structure from an ordered to a disordered conformation，and resulted in the exposure of buried hydrophobic groups and a significant increase in surface hydrophobicity. Meanwhile，the composite at the SLP and PC mass ratio of4∶1 had the smallest particle size，the highest surface hydrophobicity and the optimal interfacial activity. These properties facilitated its rapid adsorption at the air-water interface and remarkable reduction of interfacial tension，thereby constructing a thick composite film with high viscoelasticity at the interface. In summary，PC can effectively regulate the structural characteristics of SLP and enhance its interfacial properties.