Abstract: In order to explain the relationship between the structural properties (such as hydrophobicity and molecular flexibility), dynamic conformational changes during interfacial adsorption and system energy of sarcoplasmic proteins, and more broadly, to understand their functions, sarcoplasmic proteins were extracted from pork, fish and chicken meat and evaluated for amino acid composition, some important physicochemical properties, conformation, emulsifying properties and oil-water interfacial properties. The results showed that chicken sarcoplasmic protein had higher contents of phenylalanine and tyrosine as well as significantly higher particle size and surface hydrophobicity than pork and fish sarcoplasmic proteins (P < 0.05). There was no significant difference in the rate of conformational change within the same time period between pork and chicken sarcoplasmic proteins (P > 0.05), but the rate of conformational change was significantly slower in fish sarcoplasmic protein (P < 0.05). Compared with pork and chicken sarcoplasmic proteins, the interfacial diffusion rate of fish sarcoplasmic protein was significantly higher (P < 0.05) but no significant difference was seen between chicken and pork sarcoplasmic protein (P > 0.05). The emulsifying activity of fish sarcoplasmic protein was significantly lower than that of pork and chicken sarcoplasmic protein (P < 0.05), but the emulsifying activity of pork sarcoplasmic protein was only slightly lower than that of chicken sarcoplasmic protein (P > 0.05). The emulsifying stability of fish sarcoplasmic protein was the lowest among the three sarcoplasmic proteins (P < 0.05). Principal component analysis showed that pork and chicken meat sarcoplasmic proteins had similar properties, which were significantly different from those of fish muscle sarcoplasmic protein. The emulsifying activity and emulsion stability of sarcoplasmic proteins were strongly correlated with the surface hydrophobicity, zeta potential and conformational change rate, and the diffusion rate was strongly correlated with the solubility.

Key words: sarcoplasmic protein, amino acid composition, protein conformation, interfacial properties, emulsifying properties