Calcium binding of peptides derived from enzymatic hydrolysates of whey protein concentrate

This study was carried out to investigate the peptides derived from enzymatic hydrolysates of whey protein concentrate. The physiological activity of peptides in whey protein may be used in food additives to promote the absorption of calcium and prevent bone disorders. The whey protein was hydrolysed by trypsin, and the separation of peptides, the properties of hydrolysates and the analysis of the ability to inhibit the formation of calcium phosphates were then investigated. Calcium-binding peptides were produced by tryptic hydrolysis of whey protein concentrate and further purified by precipitation and chromatography on DEAE-cellulose. The hydrolysates were loaded onto an ion-exchange column, followed by stepwise elution with 0, 0.25, 0.5, and 0.75 m NaCl in equilibration buffer to separate the peptides. Trypsin hydrolysates were shown to peak with 0.25 m NaCl and 0.5 m NaCl. The results of SDS-PAGE analysis showed that the peptides with a small molecular weight of about 1.4 to 3.4 kDa were present in the fraction resulting from 0.25 m and 0.5 m NaCl stepwise elution by ion-exchange chromatography of tryptic hydrolysates. The results of this study show that the whey protein hydrolysates produced by the action of trypsin have the ability to inhibit the formation of calcium phosphates.