The Effectiveness of Clove Extract on Oxidization-Induced Changes of Structure and Gelation in Porcine Myofibrillar Protein

This study aimed to investigate the structural characteristics and gelation behavior of myofibrillar proteins (MPs) with or without clove extract (CE) at different oxidation times (0, 1, 3, and 5 h). Circular dichroism spectra and Fourier transform infrared spectra showed that samples with CE addition had significantly higher alpha-helix content after oxidation than those without CE addition. However, prolonged oxidation (5 h) would make the effect of CE addition less pronounced. Similarly, the ultraviolet-visible (UV) spectra analysis revealed that CE controlled the oxidative stretching of the protein tertiary structure and reduced the exposure of aromatic amino acids. In addition, the particle size and turbidity values of the CE group significantly decreased after oxidation compared to the non-CE group. CE increased the gel strength by 10.05% after 5 h of oxidation, which could be observed by scanning electron microscopy (SEM) as a more homogeneous, dense, less porous, network-like gel structure. Therefore, these results showed that oxidation induced significant changes in the structure and gel properties of MPs, but the addition of CE effectively inhibited these destructive changes.