Structure and characterization of laccase-crosslinked α-lactalbumin: Impacts of high pressure homogenization pretreatment

The effect of high pressure homogenization (HPH) pretreatments (0, 20, 40, 60, 80, 100, and 120 MPa for 4 cycles) on structure, physicochemical properties and functionality of laccase-treated α-lactalbumin (α-LA) was examined in this experimental study. Mass spectrometry and gel filtration chromatography revealed that monomers of laccase-treated α-LA decreased remarkably, and oligomers (dimers, trimers and tetramers) and polymers were formed with homogenization pressures ranging from 0 to 120 MPa. The HPH treatment exposed more α-LA tyrosine residues, which were further catalyzed by laccase to form dityrosine. Additionally, fourier transform infrared spectroscopy indicated that there were lower α-helix and higher random coil contents in laccase-treated α-LA with increasing homogenization pressure. The HPH pretreatment increased the emulsifying and gel properties of laccase-treated α-LA. Thus, the HPH pretreatment enhanced the crosslinking degree of laccase-treated α-LA as well as its functionality.