Preparation of emulsified lard based on octenyl succinic acid starch /whey isolate protein: Force on emulsification and interfacial properties

This study examined the emulsification of lard with different concentrations of octenyl succinic acid starch (OSA-S) and whey isolate protein (WPI) and explored the interaction mechanism of the particles at the molecular level. Results showed that the emulsification activity index, emulsion stability index and absolute value of zeta potential all increased with increasing OSA-S to WPI ratio, peaking at 3.40 m²/g, 223.68 min, and 36.98 ± 0.46 mV at 5:1. OSA-S reduced the droplet diameter (532.34 ± 9.05 nm) and increased the oil–water interface thickness according to microscopic observation. The rheological results showed that OSA-S increased the elastic (G′) and viscous (G″) moduli and viscosity of the emulsions. The molecular simulation results confirmed that -OH, -COOH and C-O-C are mainly involved in the hydrogen bonding, hydrophobic and electrostatic forces between OSA-S and WPI. The molecular dynamics results showed that the β-lactoglobulin (β-LG)/OSA-S complex had lower binding energy (-46.941 kJ/mol) and RMSD (0.242 Å) with higher Rg (1.956 Å) as compared to β-LG. This study expanded the deep processing of lard industry and more applications of OSA-S.