BACKGROUND　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.　RESULTS　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.　CONCLUSION　These　findings　revealed　the　feasibility　of　transforming　octopus　scraps　into　a　novel　functional　calcium　chelate　based　on　peptides,　promoting　environmental　sustainability.　(c)　2018　Society　of　Chemical　Industry