Abstract: In this study, eight commercially available dry-cured Spanish mackerel were compared for difference in the composition and contents of umami substances. Besides, taste activity values (TAV) and monosodium glutamate (MSG) equivalents were calculated and analyzed to determine the substances that contribute the most to the umami taste of dry-cured Spanish mackerel. The results showed that the dry-cured Spanish mackerel had a prominent salty, umami and kokumi taste, and its umami taste was mainly imparted by glutamic acid, umami peptides, lactic acid and other umami or umami-enhancing substances. The TAV value of glutamic acid was greater than 1 (except for samples 3, 5, and 7), showing its outstanding contribution to the umami taste of dry-cured Spanish mackerel. The sensory analysis of the ultrafiltration components and study of the peptide molecular mass distribution showed that small peptides with a molecular mass of less than 1 000 Da had an important contribution to the umami taste of the product. In addition, long-term air-drying could promote the production of lactic acid and umami peptides, but with the loss of water, the bitterness and salty taste were enhanced; the auxiliary ingredients sucrose and liquor could inhibit the production of lactic acid, while sucrose could promote the production of glutamic acid to a certain extent. It is worth emphasizing that the nucleotides in the eight samples were degraded into bitter substances such as inosine (HxR) and hypoxanthine (Hx), and long-term air-drying may promote the accumulation of HxR and Hx.

Key words: dry-cured Spanish mackerel; umami substances; taste activity value; monosodium glutamate equivalent