Structural and functional characterization of calcium and iron-binding peptides from mung bean protein hydrolysate

This work was aimed at producing peptides containing calcium and iron-binding capabilities from mung bean protein extract after enzymatic hydrolysis. Mung bean protein hydrolysates were separated by ultrafiltration into eight fractions, and assayed for calcium and iron-binding properties. The < 5 kDa fraction was the most active and was separated by size exclusion chromatography into 4 fractions. Fraction 2 had the most active calcium and iron-binding activities, and further identified by mass spectrometry coupled with FindPept tool. Potential peptides sequences (133) were identified and 10 with high contents of leucine, isoleucine and aspartic acid were synthesized. Peptides LLLGI, AIVIL and HADAD were the best calcium binders while PAIDL was the most potent iron-binding peptide. The presence of L or I at the C- or N-terminal but not together at both terminals may have contributed to better calcium-binding ability. These peptides are potential ingredients to formulate functional foods with enhanced mineral-binding properties.