Abstract:

The nutritional components including ash, fat, protein, oligopeptide, free amino acid composition, free fatty
acid composition and the volatile compounds were investigated to evaluate the nutritional value and characteristic flavor
of air-dried fermented blunt snout bream (Megalobrama amblycephala). The results showed that the contents of protein,
oligopeptide, fat, ash, and free amino acids were 32.72%, 4.26%, 9.40%, 9.38%, and 0.12% in air-dried fermented M.
amblycephala, respectively. The fermented fish contained all the essential amino acids, and the contents of lysine and
methionine accounted for 3.31% and 1.26% of the total free amino acids, respectively. Moreover, flavor amino acids
(aspartic acid, glutamic acid, glycine, alanine, serine and proline) and umami amino acids (aspartic acid, glutamic acid,
glycine and alanine) constituted 85.64% and 51.07% of the total free amino acids, respectively. Unsaturated fatty acids
(USFA) accounted for 68.80% of the total free fatty acids with C18:1 being the most abundant USFA. The total content of
polyunsaturated fatty acids was 21.98%, including C20:5 (eicosapentaenoic acid, EPA) and C22:6 (docosahexaenoic acid, DHA)
accounting for 0.40% and 0.89%, respectively. In addition, odd-carbon fatty acids (pentadecanoic acid and heptadecanoic
acid) were also detected in air-dried fermented M. amblycephala. The fermented fish was rich in volatile compounds,
and the contents of aldehydes and alcohols were 16.65% and 10.91%, respectively. These results indicated that air-dried
fermented M. amblycephala had excellent nutritional composition including high contents of flavor amino acids, unsaturated
fatty acids and volatile compounds, which are all conducive to the formation of its characteristic flavor.

Key words: air-dried fermented Megalobrama amblycephala, nutritional value, characteristic flavor, free amino acid, free fatty acid, volatile compound