Supercritical carbon dioxide extraction of oils from Andean lupin beans

Oil extraction from Andean lupin beans (Lupinus mutabilis SWEET) via supercritical carbon dioxide (scCO2) was studied on both lab scale and pilot scale. On the lab scale, the effect of pressure, solvent-to-feed ratio (S/F), sample particle size and temperature on oil yield were evaluated. The oil quality (fatty acid [FA] composition and tocopherol content) were investigated. Five-hour scCO2 extraction yielded about 86% oil of Soxhlet extraction (using hexane as solvent). The fraction of unsaturated FA rose with extraction pressure at specific time. High tocopherol contents were detected in oils extracted at low pressure. An increase in temperature was unfavorable to oil and tocopherol yield, thereby confirming the validity for preserving oil extract quality under a mild scCO2 extraction condition. Oil quality and yield did not have identical optimum settings, opening up possibilities for producing different qualities of oils. Pilot-scale extraction offered comparable oil yield to lab-scale extraction at similar S/F ratio. Economic evaluation showed that it is promising to implement industrial scale scCO2 process for lupin oil extraction. It was predicted that, at a specific industrial scale of extraction (2 × 1000 L, 550 bar, 40°C and S/F of 24), the manufacturing cost of oils got close to actual commercial production cost.