Influence of Extrusion Processing on Fatty acids Retention in Full-fat Flaxseed (Linum usitatissimum L.) Meal

Abstract

Background: 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 extrusion processing on fatty acids retention in full-fat flaxseed meal. The ranges of processing variables selected using central composite design were: barrel exit temperature (BET) of 76.3-143.6°C; screw speed (SS) of 59.6-160.5 rpm and feed rate (FR) of 26.4-93.6 kg/h.Results: The extrusion processing at different barrel temperatures, screw speed and feed rate did not showed gradual decrease or increase in palmitic, stearic, oleic and linoleic acid contents. The amount of α-linolenic acid retention in extruded samples ranged from 92% to 99.2%. Optimal operating conditions were established; BET (138.4-138.8°C), SS (160-160.5 rpm) and FR (26.4-34.1 kg/h) for maximum (98.3-98.8%) retention of α-linolenic acid. This effect was mainly dependent on BET (p≤0.01), whereas mutual interaction effect of BET, SS and FR was found to be non-significant (p˃0.05).Conclusions: The results of this study demonstrated that the extrusion processing can be successfully explored to produce fatty meals with significant fatty acids retention for commercially food or feed purposes.