Structural characterization and interfacial properties of yeast cytoplasmic protein crosslinked by laccase enzyme

In the present work, yeast cytoplasmic protein (YCP) was modified enzymatically by laccase in the presence and absence of ferulic acid (FA) to improve their technofunctional and interfacial properties. The 3 h, 18 h and 24 h reaction times were selected to represent low, medium and high levels of crosslinking based on the proportion of protein >150 kDa. In samples with FA, LC-MS/MS analysis found the greatest prevalence of linkage was in the form of diferulic acid, whereas those without FA had a greater incidence of linkages in the form of dityrosine and isodityrosine. Air/water interface analysis revealed that non-FA modified YCP had quicker adsorption and an enhanced effect on lowering surface tension, whereas FA modified YCP had slower transfer to the interface. Overall, the relationship between the structure and technofunctional properties of laccase-modified YCP was elucidated. Modification with laccase has the potential to further improve the emulsifying capabilities of YCP.