Haem extraction from peptidic hydrolysates of bovine haemoglobin using temperature sensitive C10E4/O/W microemulsion system

The equilibrium phase behaviour of the tetraethyleneglycol decyl ether (C10E4)/n-octane/1% peptide hydrolysates of bovine haemoglobin systems at fw = 0.5 has been studied. Fish diagrams have been completely built for two hydrolysates with 3 and 15% degree of haemoglobin hydrolysis and they do not differ much from those having NaCl 0.01 M as aqueous phase. From the knowledge of these diagrams a new method is proposed to separate selectively peptide hydrolysates from haem. Most important parameters in extraction, range of temperatures and surfactant concentrations have been established. Five extractions using 5 wt.% C10E4/n-octane/1% hydrolysates (degree of haemoglobin hydrolysis DH = 15%) at 27 °C allowed to eliminate 98% of starting haem, which is concentrated in the middle microemulsion phase, while maintaining 94% of the starting peptide population. In the same conditions, the hydrolysate DH = 3% presents 99.6% of haem elimination and maintains 85.6% peptides in aqueous phase. Well defined feasibility of the selective extractions and process conditions are established to provide depleted haem aqueous phase.