Isolation and identification of flavour peptides from Puffer fish (Takifugu obscurus) muscle using an electronic tongue and MALDI-TOF/TOF MS/MS

To clarify the key flavour peptides that account for the cooked taste of puffer fish, this study was performed to examine flavour peptides extracted from the flesh of puffer fish (Takifugu obscurus). Peptides fractions (P1, P2, P3, P4 and P5) were purified from an aqueous extract of T. obscurus muscle by ultrafiltration and Sephadex G-15 gel filtration chromatography (GFC). P2 was further fractionated into P2a, P2b, and P2c by reverse phase high performance liquid chromatography (RP-HPLC). Fraction P2b elicited umami and sweet taste. The amino acid sequence of P2b subfraction was identified as Tyr-Gly-Gly-Thr-Pro-Pro-Phe-Val (836.4Da) by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF/TOF MS/MS). Hydrophilic amino acids residues Tyr, Gly, Gly, Thr, and Phe are likely to contribute to the umami and sweet taste of this octapeptide. The results of this study suggest this peptide is one of important components of the 'mellowness' and 'tenderness' taste of the T. obscurus.