In the present study, the effects of pulsed electric field (PEF) on pale soft exudative-like (PSE-like) chicken myofibrillar protein gel properties and conformational modification were investigated by molecular dynamics simulation. The potential mechanism of gel properties change was explored, so as to broaden the industrial application of this emerging food processing technology and to provide a novel method for enhancing abnormal meat products economic benefit in poultry processing.

Myofibrillar protein was extracted from PSE-like chicken. Effect of PEF under 8, 18 and 28 kV·cm^-1 electric field intensity (800 Hz, duty cycle 47%) were compared with untreated samples of PSE-like chicken myofibrillar for turbiscan stability index (TSI) and rheological properties, and the PEF simulation system of 18 kV·cm^-1 electric field strength was established by molecular dynamics simulation technology. The root mean square deviation (RMSD), root mean square fluctuation (RMSF) and the overall conformational changes of proteins were collected to explore the mechanism of PEF treatment on the molecular conformational changes of myofibrillar proteins in PSE-like chicken, and the effects of PEF on the conformational stability, water holding capacity (WHC) and rheological properties of myofibrillar protein extracted from PSE-like chicken were also evaluated.

The TSI of the PSE-like chicken myofibrillar protein system treated by PEF with various field strengths had a smaller slope, which indicated that the protein system was more stable than the untreated sample. The results of WHC of protein gel were 18 kV·cm^-1 (81.42%)>28 kV·cm^-1 (79.46%)>8 kV·cm^-1 (77.82%)>0 kV·cm^-1 (76.15%). The rheological properties demonstrated that the changes of storage modulus (G') and loss modulus (G") had the same trend as that of WHC, and the treatment of 18 kV·cm^-1 significantly improved the G 'and G" of myofibrillar protein gel (P<0.05). The molecular dynamics simulation result of 30 ns under 18 kV·cm^-1 PEF revealed the polymer protein model acted higher RMSD value and more obvious RMSF fluctuation after treatment, which reflected that the secondary structure of protein molecule was uncoiled and unfolded, α-helix was transformed into irregular crimp, protein polypeptide chain was expanded, amino acid residues were exposed, and protein molecules displayed higher flexibility. Interactions of protein-protein and protein-water have been modified, such as electrostatic interaction, hydrogen bond, disulfide bond, hydrophobic interaction. However, when the electric field intensity increased to 28 kV·cm^-1, myosin aggregated due to the enhancement of protein-protein interaction, which reduced the effect of PEF on protein property.

The 18 kV·cm^-1 PEF changed the inherent spatial structure of PSE-like chicken myofibrillar protein, the exposure of hydrophobic groups and the formation of hydrogen bonds enhanced the binding of protein and water molecules and the interaction between protein molecules, thus improving the stability and rheological properties of PSE-like chicken myosin gel, which contribute to better gel WHC and elastic network structure.