Comparative Study on the Structural and Interfacial Properties of Proteins Extracted From Peanut Kernels and...

This study systematically characterizes and compares the structural and functional properties of peanut protein isolates from native kernels (LPPI) and hot-pressed meal (HPPI) to identify differences in emulsification stability mechanisms. Comparative analysis between peanut protein isolate extracted from peanut kernels (LPPI) and protein from hot-pressed peanut meal (HPPI) revealed significant structural disparities. LPPI exhibited higher molecular weight subunits (65 kDa), elevated β-sheet content (39%), and enhanced surface hydrophobicity. In contrast, HPPI showed subunit degradation (absence of 65 kDa conarachin II), increased α-helix content (13%), and reduced solvent-exposed aromatic residues. These structural modifications directly influence interfacial behavior. LPPI demonstrated improved adsorption kinetics and formed viscoelastic interfacial films with a higher complex modulus. Emulsions stabilized by LPPI exhibited smaller droplet sizes and a lower Turbiscan Stability Index, attributed to its capacity to overcome interfacial energy barriers through rapid adsorption and steric stabilization. The deterioration of HPPI's emulsification performance was mechanistically linked to thermal-induced subunit dissociation, which impaired hydrophobic interactions and interfacial film cohesion. These findings establish critical structure-function relationships that help explain performance differences between native and hot-pressed peanut proteins, providing a theoretical foundation for developing targeted modification strategies to enhance the functional value of peanut meal by-products in emulsified food systems.