Pressurized fluid treatment of barley and canola straws to obtain carbohydrates and phenolics

Abstract

Canada produces annually vast amounts of barley and canola straws. In this study, barley and canola straws were hydrolyzed using subcritical water (sCW) and pressurized aqueous ethanol (PAE) at 140–220 °C, 50–200 bar and 20–100% (v/v) ethanol concentrations for maximum removal of carbohydrates and phenolics. Total carbohydrates, phenolics, antioxidant activity and brown color formation were quantified via UV-spectrophotometer. Temperature and ethanol concentration were important process parameters for the removal of biocompounds from barley and canola straws. Optimum process conditions for removal of phenolics (45.4 ± 1.8 mg GAE/g barley straw and 52.9 ± 2.0 mg GAE/g canola straw) and carbohydrates (527.6 ± 0.5 mg GE/g barley straw and 442.7 ± 14.8 mg GE/g canola straw) were 180 °C, 50 bar and 20% ethanol. Furthermore, 54 and 45% of total lignin were removed using PAE (20%) from barley and canola straws, respectively. The FT-IR, TG, DTG and SEM analysis confirmed the removal of non-cellulosic materials.