Enhancing lupin protein extraction and functionality through defatting: Impact of different solvents

This study evaluated GRAS (Generally Recognized As Safe) solvents-ethyl acetate, ethanol, supercritical CO₂ (scCO₂), and scCO₂ followed by gas-expanded ethanol (scCO₂ + GLX)-for defatting lupin flour before protein extraction, compared to hexane-defatted and non-defatted flours (control). Ethanol, ethyl acetate, and scCO₂ + GLX showed the highest oil yields (6.7-8.3 %). Fatty acid profiles were similar, but γ-tocopherol content varied, with ethyl acetate and scCO₂ + GLX recovering ∼11 μg/100 g. Compared to the control, emulsion stability increased by 203 % with ethanol, and foam capacity rose by 134 % with scCO₂ + GLX. FTIR revealed protein structural changes, especially after high-pressure treatments. Defatted samples showed up to 10 % higher protein isolate yield and purity. Solubility at pH 7 and foaming improved by up to 59 % and 143 %, respectively, compared to the control. All isolates formed stable emulsions (zeta potential > -28 mV). These findings support the use of GRAS solvents to enhance protein recovery and functionality in food applications.