Structural characteristics of Sheldrake meat and secondary structure of myofibrillar protein: effects of oxidation

The present study aimed to investigate the effects of oxidation on physicochemical properties of Sheldrake meat and secondary structure of myofibrillar proteins. Sheldrake breast meat was treated with hydroxyl radical generating systems containing different hydrogen peroxide (H₂O₂) concentrations. Upon oxidation, the water-holding capacity of Sheldrake meat decreased while toughness increased. Myofibrillar proteins were extracted from the non-oxidized and oxidized meat and heat-treated to form myofibrillar protein gels. It was found that 2-thiobarbituric acid (TBARS), protein carbonyl content, and disulfide bond values increased with H₂O₂ concentration. Raman spectroscopy analysis of the myofibrillar protein gels showed that oxidation led to protein unfolding, decreased α-helix structure, and increased β-sheets, β-turns, and random coils structures. Changes in the secondary structures of proteins affected the water-holding capacity and textural properties of myofibrillar protein gels. Water-holding capacity of the myofibrillar protein gels decreased with H₂O₂ concentration. Oxidized myofibrillar protein gels showed reduced hardness, springiness, and cohesiveness.