Subcritical water extraction of bio-molecules from lentil biomass

Abstract

Solubility of glucose and lactose in subcritical water (SCW) was first determined at different pressures and temperatures. Sugar solubility increased with temperature but decreased with an increase in pressure. Then, carbohydrates and phenolics were extracted from lentil husk and cotyledon using SCW. Effect of temperature (120-180°C), pressure (15-120 bar), flow rate (2-5 mL/min), pH (4-10) and ethanol content (0-80%, v/v) in pressurized ethanol+water mixtures were evaluated. For lentil husk, the optimum yield of carbohydrates (60.54±1.32 g/100 g husk), pentosans (18.26±1.47 g/100 g husk) and phenolics (4.78±0.15 g/100 g husk) were obtained at 200°C, pH of 4, 22.8% ethanol (v/v) and 65 bar. For lentil cotyledon, the optimum yield of carbohydrates (61.66±0.72 g/100 g cotyledon) and phenolics (2.05±0.06 g/100 g cotyledon) were obtained at 172.9°C, 80.2 bar and pH of 6.2. The findings demonstrate that SCW extraction is a potential alternative to conventional extraction to obtain carbohydrates and phenolics from lentil.