Abstract:Alkaline protease hydrolysate was isolated from codfish muscle, desalinated using DA201-C macroporous resin, and purified using SP Sephadex C-25 ion-exchange chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC). The final product comprised of two bitter peptides at a relatively high concentration. Peptide structures were characterized by liquid chromatography/time-of-flight tandem mass spectrometry (LC-TOF-MS/MS), while bitterness intensity was evaluated by a combination of sensory evaluation and Q value. Their amino acid sequences were determined using an amino acid analyzer as HWPWMK (His-Trp-Pro-Trp-Met-Lys) and AVVLII (Ala-Val-Val-Leu-Ile-Ile). The amino acid composition of bitter fractions C7 and S9 was also analyzed; their Q values were determined as 6.03 and 6.79 kJ/mol, while their bitterness intensities were determined by sensory evaluation as 9 ± 0.8 and 8.2 ± 1.6, respectively. Q values of the purified bitter peptides S9purity and S10purity were 8.85 kJ/mol and 8.53 kJ/mol, while their bitterness intensities were 9.4 ± 0.8 and 8.9 ± 0.9, respectively. The bitter peptides isolated and purified from the codfish hydrolysate in this study are new members of the bitter peptide family and provide data for further study.
