Mass spectrometric characterization and thermostability of turkey myoglobin

Pink color defect (PCD) is a major quality problem in the turkey industry leading to pink appearance of pre-cooked, uncured turkey. The present study determined the molecular mass of turkey myoglobin (Mb) using mass spectrometry and characterized the thermostability of turkey Mb, in comparison with beef Mb, to elucidate the molecular basis of PCD. Purified turkey and beef myoglobins were analyzed using Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry. The thermostability of turkey and beef oxymyoglobins was examined at pH and Mb concentrations (pH 6.2 and 0.04 mmol/L for turkey; pH 5.6 and 0.15 mmol/L for beef) reflecting inherent conditions in these meats. Turkey and beef oxymyoglobins were incubated at 71, 75, and 80 °C and percentage myoglobin denaturation (PMD) was determined. Molecular mass of turkey Mb (17,295 Da) was 346 Da greater than beef Mb (16,949 Da) and was approximately 300–350 Da greater than those of other red meat myoglobins, suggesting its unique primary structure. PMD was lower (P