Phosvitin phosphopeptide preparation using immobilised trypsin and enhancing calcium absorption in growing rats

We demonstrate a new, efficient method for the preparation of phosvitin phosphopeptides using immobilised-trypsin enzymolysis technology. Immobilised trypsin was prepared using a covalent binding method, and then was added to degrade egg yolk phosvitin for the production of phosphopeptides. In our results, the prepared immobilised trypsin demonstrated a higher hydrolysing activity toward phosvitin than free trypsin, and the hydrolysing activity was retained well even after trypsin was repeatedly used up to five times. Interestingly, the phosvitin phosphopeptides prepared with immobilised trypsin demonstrated a lower N/P ratio and a higher calcium-binding efficiency than those prepared with free trypsin. Furthermore, phosphopeptides significantly increased the rate of calcium absorption and serum calcium content in vivo. Based on these results, we conclude that trypsin immobilised onto chitosan has a greater phosvitin hydrolysing activity than free trypsin, and the prepared phosphopeptides can be used as a new calcium supplement to significantly increase calcium absorption in growing rats.