Effectiveness of phosvitin peptides on enhancing bioavailability of calcium and its accumulation in bones

Phosvitin was successfully purified from egg yolks by an NaCl extraction method. When 1.0% of purified phosvitin was incubated with 0.1% of Ca under ileum conditions (pH 7.0, 37 °C), 44.1% of added Ca remained soluble in the supernatant, whereas less than 15% of added Ca was found soluble in the supernatant of the control group with no phosvitin added. Purified phosvitin was subjected to tryptic hydrolysis and examined for its efficiency in enhancing Ca absorption and accumulation in bones of SD rats. The rates of intestinal Ca absorption and its accumulation in bones were significantly higher in the groups in which phosvitin peptides were added in diets, with concentrations of 0.125–0.5%, which were equivalent amounts of 25–100% of the Ca in the diets. Although no significant differences in weights or ash contents of bones were observed, higher values of Ca to ash ratios, as well as bone mineral density and bone mineral content in femurs and tibias of the phosvitin peptides groups, suggested that phosvitin peptides improved bioavailability of Ca and thus increased incorporation of Ca into bones.