INFLUENCE OF EXTRUSION PROCESSING ON TANNIN REDUCTION AND OIL LOSS IN FLAXSEED (LINUM USITATISSIMUM L.) MEAL

This study focuses on the effects of extrusion processing on tannin reduction and oil loss in flaxseed (Linum usitatissimum L.) meal. The ranges of processing variables selected using central composite design were: barrel exit temperature (BET) of 76.3-143.6C; screw speed (SS) of 59.6-160.5 rpm and feed rate (FR) of 26.4-93.6 kg/h. The experimental values of tannin reduction and oil loss obtained were from 42.9 to 77.2% and from 1.5 to 7.6%, respectively. Optimal operating conditions were established: BET (137.9C), SS (156.8 rpm) and FR (26.4 kg/h) for maximum (77.2%) reduction of tannins and minimum (3.7%) oil loss. Response variables were mainly dependent on BET, whereas significant reduction of tannins and oil loss was achieved in studied BET and SS combination of process parameters (P <= 0.05). The results of this study demonstrated that significant reduction of tannins with minimum oil loss in flaxseed meal can be achieved commercially using an extruder.