Structural characterization and stability studies of hemp peptides and chelates for efficient chelation of ferrous ions

Synthesis of peptide-iron chelates provides a novel approach to alleviating iron deficiency in humans. The study used hemp protein isolate to make hemp protein hydrolysates (HPHs), which were combined with ferrous chloride to make hemp protein peptide iron chelates (HPH-Fe). The HPH-Fe were structurally characterized and analyzed for stability. The strongest ferrous ion-binding fraction HPH-I (<3 kDa) was isolated by ultrafiltration, and Sephadex G-15 was used to obtain fractions with high ferrous ion-binding capacity (82.47%), identified by amino acid sequences as QASSDGFEWVSFK (1482.31 Da), ARVDWKETPE (1223.53 Da), ILLPSF (719.34 Da), and WLNGGP (643.32 Da). Aspartic acid, lysine, glutamic acid, glycine, and histidine in HPH-Fe were involved in the chelation reaction. HPH-Fe maintained a good chelation rate at 25-65°C, pH = 4.0-7.0, stability during 35 days of storage at ambient temperature, and in vitro digestion tolerance. This study presents HPH-Fe as a potential alternative to chemical iron supplements in food. PRACTICAL APPLICATION: Preparation of novel, highly efficient ferrous iron ion hemp peptide and its chelates by hydrolysis, separation, and enrichment using hemp protein as raw material. Aspartic acid, glutamic acid, glycine, lysine, and histidine in HPH-Fe were involved in the chelating reaction. The peptides QASSDGFEWVSFK, ARVDWKETPE, ILLPSF, and WLNGGP showed high ferrous ion binding capacity. Iron chelates of hemp protein peptides have good acid resistance, storage stability, and digestive properties.