Abstract: In this work, changes in nitrogen existing form, taste, free amino acid composition and the contents of delicious and bitter amino acids in chicken bone protein were investigated during enzymatic hydrolysis with Flavourzyme. The results indicated that both amino nitrogen and soluble nitrogen gradually increased with the extension of Flavourzyme-catalyzed hydrolysis, while peptide nitrogen first increased up to its maximum and then decreased. As the hydrolysis time was prolonged, the umami taste of chicken bone protein hydrolysate presented an increase, and the bitter taste gradually tended to be stale during later stages of the hydrolysis. The content of free amino acids reached its maximum level after 24 hours. Therefore, a large number of released tasty amino acids seem to be responsible for the flavor of chicken bone protein hydrolysate. Tricine-SDS-PAGE analysis showed that polypeptides were gradually degraded during the hydrolysis of chicken bone protein and that all peptide molecules in the 24 h hydrolysate had a molecular weight of less than 10.0 kD.

Key words: chicken bone protein, enzymatic hydrolysis, taste characteristics, amino acid, Tricine-SDS-PAGE