Abstract: The changes of volatile flavor compounds in sea bass muscle during the steaming process were evaluated by gas chromatography-ion mobility spectroscopy (GC-IMS) in this study. The results showed that 43 volatile substances were identified in steamed sea bass muscle by GC-IMS, including aldehydes, ketones, alcohols, acids and ester compounds. There were significant differences in the flavor composition of sea bass muscle with different steaming times. The contents of 3-methylbutanol, dimethyl disulfide and propionic acid were higher in fresh fish, while the contents of octanal, nonanal, 3-methylbutanal, (E,E)-2,4-octandienal, benzaldehyde, 2-heptanone, 2-butanone, 1-octen-3-ol, 1-heptanol and 1-butanol increased significantly after steaming. A total of 11 characteristic indicators with variable importance in the projection (VIP) score greater than 1 were selected by orthogonal partial least squares-discrimination analysis (OPLS-DA). The differences in the volatile flavor of sea bass muscle with different steaming times could be distinguished by heat map clustering analysis. 3-Methylbutanol, 1-heptanol, 2-furanmethanol and (E)-2-heptenal could be used as the characteristic volatile markers to discriminate between raw and cooked sea bass. These results indicated that GC-IMS could effectively distinguish fish samples according to cooking time.

Key words: Perca fluviatilis; steaming; flavor; gas chromatography-ion mobility spectroscopy; chemometrics