Changes in Colour and Myoglobin Oxidation in Chicken Meat as Affected by Antioxidants during Storage

The study aimed to investigate the effect of natural antioxidants derived from plants on the changes of colour, pH and myoglobin oxidation of chicken meat during storage. Samples of breast and thighs were divided in three groups – control (C), and treated with infusion of wild basil (T1) or oregano (T2). The meat was stored at 4 °C for 7 days and then at –20 °C up to day 90. The pH, colour, oxymyoglobin (OMb) and metmyoglobin (MetMb) were measured at 0 d, 7 d and 90 d. The antioxidant treatment affected the colour parameters of the chicken meat, as the effect differed according to the muscles and duration of storage. Contrary to breast that exhibited initially decreased yellowness (b*), in T1, the antioxidant treated thigh meat had increased lightness (L*) at 7 d and 90 d, increased b* at 0 d and decreased redness (a*) at 7 d. Duration of storage affected both breast and thigh meat colour, more visible in T1 and T2. Considerable increase in b* was observed in breast, while in thigh meat storage was associated with higher L* and lower a*. Both breast and thigh of the treated groups showed decrease in pH, particularly in the initial stages of storage. The percentage of OMb and MetMb in meat was less affected by the antioxidants. Their effect was stronger in breast, with lower OMb in T1 at the 90th day of storage. Furthermore, this group exhibited dramatic decrease in the OMb in the course of storage. MetMb increased in C and T1 during the storage period. The changes in the myoglobin redox forms in thigh meat are mainly due to storage and are similar to those observed in breast.