Novel calcium‐chelating peptides from octopus scraps and their corresponding calcium bioavailability

To reducing the massive marine pollution and resource waste caused by octopus scraps, we developed a novel octopus scraps protein hydrolysate (OSPH), which displays calcium‐chelating activity, and we investigated the chelating interaction and calcium bioavailability of OSPH‐Ca.

The structural properties of amido and carboxy groups indicated that they could be the reaction sites for chelation. The particle radius of OSPH increased by 32.25 nm after the calcium chelated with OSPH, indicating intramolecular and intermolecular folding and aggregating. The enthalpy of OSPH increased by 0.8323 after chelation, showing that bands of OSPH‐Ca needed more thermal energy to be destroyed than OSPH. Meanwhile, the chelate showed remarkable stability and absorbability under either acidic or basic conditions, which favored calcium absorption in the gastrointestinal tracts of humans. The calcium intake of OSPH‐Ca increased by 41% when compared with that of CaCl₂. In particular, OSPH‐Ca could protect calcium ions from precipitation caused by dietary inhibitors tannic acid and phytate, while calcium uptake efficiency remained at 3.35 and 1.68 times higher than that of CaCl₂.

These findings revealed the feasibility of transforming octopus scraps into a novel functional calcium chelate based on peptides, promoting environmental sustainability. © 2018 Society of Chemical Industry