Polyamide commercial membranes in flat-sheet configuration and with molecular weight
cut-o (MWCO) in the range of ultrafiltration (UF) to nanofiltration (NF) were tested for the recovery of
phenolic compounds fromclarified olive mill solid waste (OMSW) aqueous extracts. The performance
of selected membranes was evaluated in terms of productivity (permeate flux) and selectivity towards
biologically active compounds (such as phenolic compounds, flavanols, and hydroxycinnamic acids
derivatives) and total antioxidant activity (TAA) as a function of transmembrane pressure (TMP).
NF membranes produced higher permeate fluxes and a lower fouling index in comparison with UF
membranes. Retention of bioactive compounds was also significantly higher for NF membranes than
for UF membranes. In particular, membranes with MWCO in the range 150–500 Da showed rejection
towards flavanols and hydroxycinnamic acid derivatives of about 100%. On the other hand, the
rejection towards TAA and total polyphenols was of about 90% and 72%, respectively. Therefore,
NF retentate fractions appear of practical interest for the production of food additives and food
supplements due to their high antioxidant activit
