Monitoring of the functional properties and unfolding change of Ovalbumin after DHPM treatment by HDX and FTICR MS: Functionality and unfolding of Oval after DHPM by HDX and FTICR MS.

Dynamic high-pressure microfluidizaiton (DHPM) induced unfolding of proteins and enzymes could enhance the functional properties and hydrolytic ability of the molecules. In this study, the effect of DHPM on the surface activities of Ovalbumin (Oval), namely foaming and emulsifying properties, was investigated at 0, 40, 80, 120 and 160MPa. Improvement in the foaming and emulsifying properties was observed at 120 and 80MPa, respectively. Hydrogen/deuterium exchange (HDX) coupled with Fourier transform infrared spectroscopy-mass spectrometry (FTICR MS) was performed to investigate the exact unfolded region of Oval and analyze the mechanism promoting the foaming and emulsifying properties after 120 and 80MPa, respectively, compared with those at 0MPa. Prevalent unfolding of Oval after 80 and 120MPa treatment was revealed by HDX-MS, indicating a more flexible conformation induced by DHPM. However, lower deuterium incorporation was observed for the large six-stranded β-sheet. Therefore, the combined forces could enhance the flexibility and surface activities of Oval, which increased its foaming and emulsifying properties.