Influence of purification on the composition, structural and physicochemical properties of myofibrillar proteins from blue mussel (Mytilus edulis)

Blue mussel meat (Mytilus edulis) is an alternative and sustainable protein source for functional food proteins such as myofibrillar proteins. However, the impact of the purification process for obtaining myofibrillar proteins on the yield and physicochemical properties is unknown. This study investigated the effect of various washing solvents (distilled water, phosphate buffer, and NaCl solution (0.1 M vs. 0.6 M)) on protein yield, composition, solubility, and protein structure of the myofibrillar fractions. The results indicated a significant protein loss during the prewashing step with distilled water. Subsequent washing with phosphate buffer and low salt content (0.1 M NaCl) yielded higher myofibrillar protein from the mussel meat along the extraction process in comparison with 0.6 M NaCl as evidenced by size exclusion-high-performance liquid chromatography. FTIR spectroscopy detected conformational changes with more β-sheet structure in proteins extracted by high salt concentration compared to low salt. The findings of this study indicate to consider a prewashing step with distilled water followed by washing with phosphate buffer and 0.1 M NaCl to obtain myofibrillar protein powders with light color (yield of 56% corresponds to 0.18 g protein/per 15 g dry mussel meat) and preserved native protein folding. Alternatively, the prewashing step can be skipped to increase the yield of extraction to 64% (0.96 g protein/per 15 g dry mussel meat) and thus preserving more of the proteins, but the color of powder is darker. •Mussel myofibrillar proteins were extracted with different strategies.•Effect of prewashing and low/high salt concentration were investigated.•Prewashing resulted in less dry matter and lighter color of myofibrillar proteins.•Using low salt solution preserved more functional (myofibrillar) proteins and their nativity.•High salt concentration promoted conformational changes for myofibrillar proteins.