The Effects of Lipid Oxidation Product Acrolein on the Structure and Gel Properties of Rabbit Meat Myofibrillar Proteins

We investigated the effect of acrolein, a byproduct of lipid oxidation, on the structure and gel properties of myofibrillar proteins (MPs) isolated from rabbit meat. As the acrolein concentration increased, the protein carbonyl compounds significantly accumulated (p<0.05), and the total sulfhydryl content was significantly lost (p<0.05). The results of circular dichroism spectra, surface hydrophobicity, UV absorption spectra and intrinsic fluorescence spectra evidenced that acrolein caused the disruption of -helix structure, the exposure of hydrophobic sites and the unfolding of MPs. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis suggested that medium (0-1mM) and high (5-10mM) concentrations of acrolein could induce protein cross-linkage and protein aggregation, respectively. These structural changes could affect gelling properties of MPs involving gel strength and water holding capacity (WHC). The results of Raman spectroscopy indicated that moderate oxidative modification caused protein unfolding as well as the decline of -helix structure and the increase of -sheets structure in gels, thereby influencing the gel properties. Moderate oxidative modification (0-1mM) improved gel strength and WHC, while excessive oxidative modification (5-10mM) resulted in decreased gel properties.