Supercritical antisolvent fractionation of lignans from the ethanol extract of flaxseed

Supercritical antisolvent fractionation (SAF) was evaluated in the fractionation and concentration of a family of beneficial plant compounds called lignans from the ethanol extract of flaxseed. The amount of lignans obtained in different fractions was studied under varying pressures (10–30 MPa), CO2 flow rates (5–15 kg h−1) and times of treatment (60–180 min) in a three-stage fractionation column with constant temperature fixed at 313, 323 and 333 K. The determination of lignan content was performed by HPLC coupled with a coulometric array detector. The effects of each individual variable as well as their interactions were investigated using a full factorial design with three factors and two levels and the optimal conditions were calculated through response surface methodology. A statistically significant increase in lignan content was obtained after the SAF process; from an average initial lignan content of 1.66 ± 0.13 g L−1 it was possible to obtain a total lignan content ranging from 3.42 to 12.96 g L−1. We conclude that SAF is an appropriate technique for the isolation of lignans from flaxseed.