Conjugation of dual-natural milk-derived proteins with fucoidan to prepare controllable glycosylation products via dielectric barrier discharge cold plasma

This study reported that fibrillar bridges (whey protein isolate nanofibrils, WPNs) were used to associate the casein (CA) nanoparticles through the pH-driven method to obtain the self-assembled WPN-CA complexes. Then, a novel technology involving cold plasma (CP) was innovatively proposed to enhance the protective properties of complexes. The confirmation of structural transitions and interactions resulting from the adjustment of WPN-toCA ratios (WtCs) led to the identification of the complexes named WPCA (WtC1.0:1). Next, the results showed a rapid conjugation between WPCA and fucoidan (FD) with a degree of grafting of 16.03 % after 10 min CP treatment. The coupling of WPCA with FD to form conjugates was confirmed by SDS-PAGE analysis, indicating covalent bonds' formation. FTIR spectroscopy revealed an augmentation in the intensity of the -OH stretching vibration of the WPCA-FD conjugate, concomitant with a decrease in beta-turns and an elevation in beta-sheets content. Furthermore, the application of glycosylation treatment to WPCA-FD resulted in a noteworthy enhancement of both the thermal stability and antioxidant activity characteristics of WPCA. Our findings move a step forward, as CP-assisted Maillard reaction has shown potential as an efficient and energy-saving method to enhance the functional properties of milk-derived proteins in the food industry.