The application of pressurized low polarity water (PLPW) extraction to the production of flaxseed lignans-rich products has been studied, and the key geometric and process conditions, including temperature, flow rate, and total volume have been determined and optimized. Maximum amounts of lignans and other flaxseed bioactive, including proteins were extracted at 160 degrees C and 5.2 MPa. However, on a dry weight basis the most concentrated extracts in terms of lignans and other phenolic compounds were obtained at 140 degrees C and 5.2 MPa. A flow rate of 0.5 mL/min was optimal for the extraction of lignans from flaxseed (Linum usitatissimum L.) and a total volume of 30-40 mL/g of seed was required to maximize the recovery. Higher flow rates increased the rate of the extraction but required larger water volumes. Bed depth to ID ratios of 5-18 resulted in faster extraction and maximum recovery (90-95%) at water to seed ratios of 30-50 mL/g. Larger depth to ID ratios (15-18) would allow the use of lower solvent to solid ratios (14-20 mL/g) and would still result in yields of 84-90%. (c) 2005 Elsevier Ltd. All rights reserved.