Calcium-binding peptides derived from tilapia (Oreochromis niloticus) protein hydrolysate

Calcium-binding peptide was derived from protein hydrolysates. In this study, tilapia protein at a concentration of 2 % (w/v) was hydrolyzed using various proteases including Alcalase 2.4 L, Flavourzyme 1,000L, Protease GN, and papain at 50 °C, pH 8 for 6 h. It was found that the degree of hydrolysis increased with the time of the incubation in all cases. The highest calcium-binding capacity of the hydrolysate was 65 mg/g protein at 27.7 % degree of hydrolysis by Alcalase 2.4 L. The molecular weight of the calcium-binding peptides characterized by gel-filtration chromatography on a Sephadex G-25 was 1.2 kDa. The calcium-binding motif of the hydrolyzed peptides identified by the automated Edman degradation was a short peptide (Trp-Glu-Trp-Leu-His-Tyr-Trp). The results of this study suggested that tilapia protein is a good source for calcium-binding peptides.