Use of Membrane Technology for Concentration of Bioactive Peptides From Geoduck (Panopea Zelandica)

Enzymatic digestion of proteins generates biologically active peptides which can be concentrated by filtration with the appropriate membranes. This work uses a hydrolysate derived from the New Zealand geoduck Panopea zelandica and compares the effectiveness of membranes with varying molecular weight cut-offs (MWCOs) and surface charges for carrying out selective separations of the peptides. A membrane with a MWCO of 2.5 kDa was found to be most effective for obtaining the greatest differences between the permeate and retentate from the membranes when separating by size alone. For separating peptides based on charge the choice of membrane and pH was important. The results obtained suggested that each hydrolysate has different optimum conditions for achieving separation. A challenge when analysing the effects of membranes on peptide mixtures is quantifying the changes that have occurred. The work presented here introduced a multivariate approach to interpretation of complete sets of HPLC data that had not previously been used for analysis of complex peptide mixtures. This approach was used to measure the effectiveness of the membrane separations, and allowed comparisons to be drawn between these separations and the peptide bioactivity as determined using the FRAP assay