INFLUENCE OF TWIN-SCREW HOT EXTRUSION ON LINOLENIC ACID RETENTION IN FLAXSEED MEAL

Flaxseed (Linum usitatissimum L.) provides multiple nutritional benefits including high quality protein, dietary fiber and is the most abundant source of α-linolenic acid (C18:3). This study focuses on the effect of twin-screw hot extrusion on α-linolenic acid retention in full-fat flaxseed meal. The ranges of processing variables selected using Box-Behnken design were: barrel exit temperature (BET) of 120-140°C; screw speed (SS) of 200-400 rpm; feed rate (FR) of 1-2 kg/h and feed moisture (FM) of 20-30%. The amount of α-linolenic acid retention in extruded samples ranged from 89.2% to 99.3%. Optimal operating conditions were established; BET (121°C), SS (388 rpm), FR (1 kg/h) and FM (22.2%) for maximum (99.9%) retention of α-linolenic acid. This effect was mainly dependent on BET and FM (p≤0.01), whereas SS and FR imparted a lesser effect (p 0.05). The results of this study demonstrated that the twin-screw hot extrusion can be successfully explored to produce fatty meals with significant fatty acids retention for commercially food or feed purposes.