Characterization of Fe(III)-binding peptides from pea protein hydrolysates targeting enhanced iron bioavailability

• Fe(III)-binding peptides from pea-derived enzymatic hydrolysates were identified. • The iron-binding fraction was rich in Glu, Asn, Lys and Leu. • The most abundant 3–6 nmers in the fraction was dominated by consecutive Glu residues. • 15 novel peptides (<1.5 kDa) were identified as potential candidates for enhancing iron bioavailability. This investigation aimed to characterize enzymatically-derived pea peptides that act as solubilizing agents to enhance Fe(III) bioaccessibility. The pea hydrolysates were found to have an iron-binding capacity of 5.3 mg/g lyophilized powder. The Fe(III)-binding peptides were separated by immobilized metal affinity chromatography (IMAC), and then sequenced using tandem MS following an in-solution tryptic digestion. Results revealed that the Fe(III)-binding fraction was rich in Glu, Asn, Lys and Leu, and the peptides primarily belonged to the Vicilin family. After screening based on the peptides' relative abundance and physicochemical properties, 15 novel peptides below 1.5 kDa were identified as potential candidates for enhancement of iron bioavailability. Fourier Transform infrared spectroscopy (FTIR) of the hydrolysate-iron complex suggested that the principal sites of peptide binding corresponded primarily to the carboxylate groups, with amine I and II groups also evident.