Changes in quality characteristics of southern bluefin tuna (Thunnus maccoyii) during refrigerated storage and their correlation with color stability

Abstract

In this paper, we explore the quality characteristics of southern bluefin tuna during refrigerated storage at 4 °C. Moreover, partial least squares is used to understand the correlation between the quality characteristics and color stability of the tuna. The initial myoglobin content (192,533 mg/kg) was significantly higher than that on day 6 (133,760 mg/kg; P < 0.05). The content of total pigments, myoglobin, and a*/b* value (redness) showed a downward trend, whereas metmyoglobin content (MetMb%) showed an upward trend. The value of a*/b* was 0.698 on day 0 and dropped to 0.163 on day 6 with the surface browning evident. Moreover, MetMb% increased from 27.52% to 35.08% over storage period. With the prolongation of storage time, the degree of lipid and protein oxidation in tuna muscle aggravated and so did the browning tendency. A model correlating the changes in quality traits with color stability suggested that thiobarbituric acid reactive substance content was significantly and positively correlated with MetMb% (r = 0.706, P < 0.05) but negatively with a*/b* (r = −0.942, P < 0.01). The current results can provide theoretical basis for developing color protection technology, so as to better promote the development and utilization of bluefin tuna.