Fractionation of a tuna dark muscle hydrolysate by a two-step membrane process

The aim of this work is to develop a two-step membrane separation process enabling the fractionation of protein hydrolysates obtained from enzymatic hydrolysis of tuna by-products. A screening of the more appropriate UF and NF membranes was first performed in dead-end and tangential filtration cells with a model solution prepared from a commercial fish hydrolysate (Prolastin®). Optimization of UF and NF steps was then investigated through the impact of operating parameters including pressure, peptide concentration and pH of the solution on performance of two selected membranes. Finally, the coupling of UF and NF steps was investigated for the fractionation of a raw hydrolysate prepared from tuna by-products. Three different operation modes coupling UF and NF steps in batch and diafiltration configurations were tested. A fraction rich in peptides of molar mass between 1 and 4 kg mol−1 was isolated and the positive effect of diafiltration on peptide purification process was underlined.

► Coupling of membrane separation processes for fractionation of fish protein hydrolysates.
► UF and NF steps for fractionation of peptides were optimized.
► A fraction rich in peptides of MM between 1 and 4 kg mol−1 was isolated.
► The positive effect of diafiltration on peptide purification was underlined.