Fatty acid-whey protein interactions: A multi-spectroscopic and computational study

Trans fatty acids (TFAs) play a vital role in physiological processes. Elaidic acid (EA), a prevalent TFA, emerges during the hydrogenation of vegetable oils. This study employs an array of spectroscopic and computational methods to elucidate the molecular interactions between EA and β-lactoglobulin (β-Lgb), a key whey protein. UV–Vis spectroscopy reveals the formation of a β-Lgb-(EA) complex, evidenced by distinct spectral changes. Fluorescence spectroscopy demonstrates a progressive quenching of β-Lgb's emission as EA concentration increases, with analysis confirming a static quenching mechanism. Thermodynamic parameters highlight van der Waals forces and hydrogen bonding as the primary drivers of complex stability, a finding corroborated by molecular docking data. Fourier-transform infrared (FTIR) spectroscopy indicates an increase in β-sheet and β-turn content, alongside a reduction in α-helix, following EA binding results mirrored by circular dichroism (CD) spectroscopy. Thermal stability assessments, supported by melting temperature ($T_m$) measurements and molecular dynamics (MD) simulations, show enhanced β-Lgb stability in the presence of EA. This is further validated by decreased root mean square deviation (RMSD) and root mean square fluctuation (RMSF) in the β-Lgb-(EA) complex, aligning with FTIR findings and underscoring the structural and thermal resilience imparted by EA binding.