Enhancing the emulsification performance of hempseed protein hydrolysate through the incorporation of sugar beet pectin: Role of interaction mechanism and interfacial behavior

Effects of incorporating sugar beet pectin (SBP) at various pH levels (3.0-7.0) on the conformation, interfacial characteristics, and emulsification performance of hempseed protein hydrolysate (HPH) were explored. The introduction of SBP stimulated the conversion of protein conformation from α-helix and random coil into β-sheet. Besides, the incorporated SBP led to noticeable deformation and disruption of the original granular structure of HPH, and caused a remarkable reduction in surface hydrophobicity and intrinsic fluorescence intensity. FTIR analysis and pH-dependent molecular docking verified that hydrogen bonding, hydrophobic interactions, and electrostatic interactions predominantly drove the interaction between HPH and SBP. Overall, the interaction of HPH with SBP limited protein diffusion to the interface but facilitated their rearrangement at the interface, ultimately contributing to the development of highly viscoelastic interfacial layers with reinforced intermolecular interactions. Consequently, the emulsifying activity and emulsion stability within the acidic pH range (3.0-6.0) were significantly improved by SBP binding, notably at pH 5.0. Furthermore, within this pH range, HPH-SBP emulsions exhibited smaller droplet sizes with a more homogeneous distribution and stronger electrostatic repulsion relative to HPH emulsions; yet, the apparent viscosity and elastic modulus of HPH-SBP emulsions were conspicuously elevated in the presence of SBP, conducing to emulsion stabilization.