Abstract: Changes in the total viable count (TVC), total volatile base nitrogen (TVB-N) content, thiobarbituric acid (TBA) value, K value, water distribution, microstructure and protein degradation of whole, gutted and filleted turbot were determined during ice storage, and the taste profiles were collected using an electronic tongue. Meanwhile, the volatile substances were detected by gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that the filleted fish had higher values of TVC, TVB-N and TBA than the whole and gutted fish during ice storage, with a TVC value of 7.05 (lg (CFU/g)) being recorded after 12 days, exceeding that at the end of storage. In addition, the content of salt-soluble protein in the fillet decreased to the lowest level of 1.57% on day 19, which was accompanied by a greater degree of muscle fiber breakage and increased space between muscle fibers. Compared with the whole fish, the gutted fish had higher TVC and TVB-N values of 6.58 (lg (CFU/g)) and 16.72 mg/100 g on day 19, respectively. The percentages of free water in the whole and gutted fish at the end of storage were 0.21% and 0.28%, respectively, which were significantly lower than that of the fillet (P < 0.05), indicating better maintenance of muscle tissue structure in the whole and gutted fish. Finally, orthogonal partial least squares-discriminant analysis (OPLS-DA) and clustered heatmap analysis based on the measured GC-IMS fingerprints distinguished the whole, gutted and filleted fish at different storage times. In conclusion, the rate of quality deterioration of the fillet was the fastest, followed by the gutted fish, and the quality of the whole fish deteriorated at the slowest rate under ice storage conditions. The results of this study can provide a reference for developing an alternative to traditional live circulation of turbot.

Key words: Scophthalmus maximus; ice storage; whole fish; gutted fish; fillet; quality