Hydrolysis of Soybean Protein Improves Iron Bioavailability by Caco-2 Cell

Iron is an important trace metal element in human body. Iron deficiency affects human health, especially pregnant women and children. Soybean protein is a popular food in Asia and contains a high amount of iron (145.70 ± 0.74 μg/g); however, it is usually reported as an inhibitor of iron absorption. In this study, the effect of hydrolysis on iron bioavailability of soybean protein was investigated with an in vitro digestion/Caco-2 cell model. The result showed that hydrolysis significantly enhanced the intrinsic and extrinsically added iron bioavailability of soybean protein (P < 0.05). Furthermore, the hydrolyzed soybean protein (SPH) was ultrafiltered to different molecular weight of peptides; and intrinsic iron content of SPH (> 10 kDa), as well as the iron uptake by Caco-2 cells, significantly higher than that of low molecular weight of SPH. However, when extrinsic iron was added, the SPH (< 1 kDa) were presented with highest iron bioavailability. These results indicated that hydrolysis of soybean protein improves iron bioavailability.