Effect of linoleic acid-induced oxidation on the water retention of golden pompano: Myoglobin and myofibrillar protein oxidation

This study investigated the interrelationship among changes in myoglobin (Mb) morphology, myofibrillar protein (MP) oxidation, and water-holding capacity (WHC) of golden pompano under oxidized linoleic acid (OLA). Results showed that the WHC, springiness, and chewiness of golden pompano were increased at low OLA concentrations. Compared with the control, centrifugal and cooking losses were reduced by 11.78% and 6.22%, respectively. By contrast, high concentrations of OLA showed a decreasing trend in muscle WHC. The porphyrin ring of Mb was disrupted, and the contents of heme and heme iron were significantly decreased (P < 0.05) during oxidation. The carbonyl content gradually increased, whereas total sulfhydryl decreased with the increase in OLA concentration. The α-helix contents of MP decreased and the random coil increased. The surface hydrophobicity of MP increased (≤10 mmol/L), and then gradually decreased with the increase of OLA concentrations. The Pearson analysis showed that WHC was closely related to protein oxidation. Mb would be pre-oxidized before MP due to linoleic acid oxidation, which may further promote oxidation and cause structural changes in MP, affecting WHC in golden pompano. Muscle WHC would be increased at low OLA concentrations (≤10 mmol/L), while reduced at high OLA concentrations (≥20 mmol/L).