Abstract: Deep-fried grass carp was prepared by sequentially marinating and deep frying fresh grass carp (Ctenopharyngodon idellus). The contents of water-soluble taste compounds, reducing sugars and volatile flavor compounds in fresh, marinated and deep-fried fish samples were determined and compared by high performance liquid chromatography, an amino acid auto-analyzer and headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that marination and deep frying could enhance the umami taste and that the taste activity value (TAV) of Glu in the intermediate and finished products was greater than one. There was no significant difference in IMP contents between the deep-fried and fresh grass carp, suggesting retention of the original umami taste. The contents of reducing sugars in the deep-fried sample were significantly reduced as compared to the fresh sample. GC-MS analysis demonstrated that there were 72 volatile compounds in the deep-fried grass carp mainly including aldehydes and alkanes. Based on their odor activity values (OAVs), 2,4-decadienal, 1-octen-3-ol, nonanal, hexanal, 2-decenal, decanal and 3-methyl-butanal made an important contribution to the overall flavor of deep-fried grass carp.

Key words: grass carp, deep frying, water-soluble taste compounds, reducing sugars, volatile flavor compounds