61D-3 |
Hen eggshell matrix proteins enhance calcium transport in the human intestinal epithelial cells |
W. DAENGPROK1, P. Rupa, and Y. Mine. (1) Department of Food Science, University of Guelph, Guelph, ON N1G2W1, Canada Osteoporosis is now becoming one of the most serious aged population's health concerns and a means needs to be found for increasing calcium (Ca) intake. Milk casein phosphopeptides have been demonstrated to enhance the intestinal absorption of Ca by facilitating paracellular absorption. Hen eggshell is composed of 97% solid (98% of Ca carbonate) and a trace of matrix proteins. The eggshell is disposed as a waste product. Recently, hen eggshell powder has been proposed as a new source of Ca supplement in many health foods in Japan. However, its bioavailability has not been evaluated in scientific level. In this study, we found that eggshell matrix proteins enhance Ca transport in the human intestinal epithelial cells. Our aim was to study the biological functions of eggshell matrix proteins on Ca bioavailability using an in vitro model of Caco-2 cells. The eggshell proteins were extracted by demineralizing with 20% acetic acid. The Caco-2 cells were maintained in Dulbecco's modified Eagle's medium and were seeded onto a 12-well transwell polyester membrane (0.4 micron) to make a monolayer. After became confluent (14 days), the cells were washed with Ca+-free Hank's balanced salt solution and subjected to Ca transport experiments. The amount of Ca in the basolateral side was determined using a Ca assay kit. The hen eggshell powder contained 0.89-1.0 % (w/w) proteins. The rate of transepithelial Ca transport across Caco-2 cell monolayer was significantly increased in the presence of extracted eggshell matrix proteins in the apical side (50 and 100 micro gram/well) to 26.0 and 29.5%, respectively after 4 hrs incubation, while Ca solution without the proteins showed 8.0% transport rate for Ca. On the basis of these results it can be concluded that eggshell matrix proteins could enhance Ca bioavailability. These results suggest that hen eggshell proteins could offer a new insight for improving Ca bioavailability as nutraceutical. Caco-2 cell is a good model as human small intestine for studying Ca transport in vitro.
Session 61D, Nutraceuticals & Functional Foods II
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