Application of a novel naturally-derived emulsifier mannosylerythritol lipid-A for improving emulsification and gel property of myofibrillar protein based on biosurfactant-protein interaction

Mannosylerythritol lipid-A (MEL-A) is one of natural glycolipid biosurfactants with extensive applications into food and cosmetics field. This study focused on the effect of MEL-A on physicochemical properties of myofibrillar protein (MP) from chicken and explained the underlying mechanism between biosurfactant-protein interaction from molecular level. Specifically, the mixed MP-MEL-A emulsions were prepared and characterized by rheological properties, protein structure alternations and emulsifying and foaming properties. The study showed that the addition of MEL-A promoted the formation of smaller droplet size, resulting from the electrostatic interaction and hydrophobic interaction inside the emulsion. Further investigations of SEM and SDS-PAGE indicated the protein aggregation phenomenon induced by MEL-A. With the increase of MEL-A content, the apparent viscosity, elasticity and sulfhydryl content increased significantly. Moreover, the decrease of α-helix and the increase of β-sheet in protein secondary structure proved that MEL-A leaded to the formation of protein network for instance in gel. Besides, the addition of MEL-A also enhanced the emulsifying and foaming properties of emulsions, 1.5% of which seems to be the best choice. These results implied the great potential of MEL-A applied into meat gel product industry.