Effect of Super High Pressure Processing on the Structure and Physicochemical Properties of Lactoferrin in Different Buffer Systems

This paper measured the effect of high pressure processing on the structure and properties of lactoferrin (LF) in different buffer systems [(phosphate buffer (PBS), Tris-HCl buffer (Tris-HCl), citrate buffer (CBS)] by Zeta potential, free sulfhydryl content, ultraviolet spectrum, fluorescence spectrum, circular dichroism and protein solubility. The results showed that the resistance of LF to high pressure in the three buffers was as follows: CBS>Tris-HCl>PBS, that was, the tertiary structure and solubility of LF in PBS were most easily changed by high pressure. The adsorption of anions in the buffer solution caused the isoelectric point of LF to change. The surface Zeta potential of LF in PBS, CBS, and Tris-HCl was -3.86-20.07, -6.89-19.6 mV and 1.24-23.37 mV, respectively. Accordingly, the adsorption capacity of anions was CBS>PBS>Tris-HCl. 600 MPa treatment in Tris-HCl at pH 7 caused a large amount of precipitation of LF, where the free sulfhydryl content reached the highest, 6.23 μmol/(L•g), and the protein solubility was the lowest, 45.28 μg/mL. At pH 3, the α-helix content of LF was significantly lower than other samples, and the content of random coils was significantly higher than other samples, indicating that the secondary structure of LF was relaxed under acidic condition and was more susceptible to high pressure. © 2021, Editorial Office of Journal of CIFST. All right reserved.