Concentration of phenolic compounds from strawberry (Fragaria X ananassa Duch) juice by nanofiltration membrane

The aim of this study was to evaluate the concentration of bioactive compounds from strawberry juice by nanofiltration. Two different processes were analyzed, (1) nanofiltration of in natura juice (NF SN) and (2) nanofiltration of microfiltered juice (NF MF). Color, the total phenolic content (TPC), total monomeric anthocyanins content (AC) and antioxidant activity by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods were determined. The average permeation flux was 4.0 L h−1. m−2 for NF SN and 3.0 L h−1. m−2 for NF MF. For the NF SN and NF MF processes, when the volume reduction factor (VRF) was increased (VRF = 2), the TPC and AC increased 20% and 50%, respectively. The same behavior was observed for antioxidant activity for ABTS and DPPH, which increased about 100% and 60% respectively. The concentration of the major anthocyanin detected by HPLC, pelargonidin-3-O-glycoside, presented retention up to 95% and the antioxidant activity can be correlated with this component content. The nanofiltration showed to be an effective method for concentration of phenolic compounds from strawberry juice without color degradation as the global color variation (ΔE*) presented low values.