Effect of ultra-high pressure on the physicochemical properties of actomyosin from bighead crap (Arstichthys nobilis)

Changes of physicochemical properties in natural actomyosin from Arstichthys nobilis induced by ultra-high hydrostatic pressure ( 100, 300, 500 MPa for 15, 30, 45 min) were investigated. The results revealed that the solubility of actomyosin decreased while the turbidity increased with the increase of pressure and time, indicating the accumulation of protein aggregates and denaturation.SDS-PAGE showed that ultra-high pressure induced the cross-linking and accumulation of actomyosin to form macromolecular substances.Ca²⁺-ATPase activity of actomyosin treated by ultra-high pressure was lost, suggesting the denaturation of actomyosin.Surface hydrophobicity of actomyosin increased when the pressure and pressurization time increased, indicating that the exposed hydrophobic residues increased upon application of high pressure. The total sulfhydryl content of actomyosin decreased while the disulfide bond content increased with the increase of pressure, which confirmed that the sulfhydryl group of actomyosin underwent oxidation to form disulfide bonds. These variations in the physicochemical properties demonstrate that the conformation of actomyosin extracted from Arstichthys nobilis changes after ultra-high pressure processing.