Modification of ovotransferrin by Maillard reaction: Consequences for structure, fibrillation and emulsifying property of fibrils

The present study first glucosylated and lactosylated ovotransferrin to acquire ovotransferrin-glucose conjugate (OGC) and ovotransferrin-lactose conjugate (OLC), respectively. Thioflavin T fluorescence result indicated that glycation could suppress fibrillation of ovotransferrin, and glucosylation exerted stronger inhibitory influence on fibril formation than lactosylation. SDS-PAGE analysis indicated that the major building blocks of OVTC fibrils, OGC fibrils and OLC fibrils were peptides, and building blocks of OGC fibrils and OLC fibrils had slightly larger molecular weight than those of OVTC fibrils. Morphology of ovotransferrin fibrils with covalent bound saccharides was closely related to type of saccharides. Both rigid and flexible fibrils were observed in OVTC fibrils and OLC fibrils, and an absence of rigid fibrils was observed in OGC fibrils. Afterwards, emulsibility of all fibrils was tested. Covalent bound saccharides weakened emulsifying property of ovotransferrin fibrils. Droplet size and rheological properties of emulsions stabilized by ovotransferrin fibrils with covalent bound saccharides were dependent on nature of saccharides. For emulsions at fixed fibril concentration of 4 wt% and oil fraction of 0.65, droplet size followed the order: OGC fibrils-stabilized emulsions > OLC fibrils-stabilized emulsions > OVTC fibrils-stabilized emulsions. Among all emulsions, emulsions stabilized by OGC fibrils had the lowest viscosity and storage modulus.