Edible proteins from coconut milk press cake; one step alkaline extraction and characterization by electrophoresis and mass spectrometry

Coconut milk press cake, the spent endosperm left over after the extraction of coconut milk, was utilized to extract additional protein under alkaline conditions. The maximum protein yield was observed at 50 °C and pH 11 and corresponded to total endosperm protein yield of 71%, favourably comparable to yields of more complex extractions. The extract was characterized by amino acid analysis and 1D SDS-PAGE, 2D electrophoresis and MS MS spectroscopy. Coconut milk and insoluble milk sediment from the same individual nuts were also analyzed.The alkaline extract reproducibly differed from the other fractions and from those reported by others in amino acid content as seen in Principal Component Analysis, and had in particular higher threonine content The peptide found in the alkaline extract but with no counterpart in coconut milk or its sediment showed IP (≈ 5) and mass (≈ 40 kDa) and matched partially glutelin from oil palm.

Research highlights► Coconut milk press cake utilized to extract additional protein in alkaline conditions. ► Maximum protein yield observed at 50 °C and pH 11-71% total endosperm protein. ► Extract characterized by amino acid analysis, 1D SDS-PAGE, 2DE and MS MS spectrometry. ► Peptide found showed IP ≈ 5, mass ≈ 40 kDa and matched partially oil palm glutelin.