Debittering Andean lupin beans via supercritical carbon dioxide extraction

Supercritical carbon dioxide (scCO₂) extraction was used to debitter Andean lupin beans (Lupinus mutabilis, SWEET) by separating quinolizidine alkaloids. ScCO₂ alone was found ineffective. Alkaloids were removed with i) a specific amount of polar cosolvent, ii) a pre-wetting of the bean flour before extraction, and iii) excessive polar cosolvent. For i) and ii), about 30 % and 60 % of alkaloids could be removed respectively, with limited effects of increasing pressure or temperature. For iii), multiple layers were observed along the sample bed. In the layer closest to the scCO₂ inlet, more than 98 % of alkaloids were removed. Thus, the strategy to remove the alkaloids was to extract them using excessive polar media. ScCO₂ as an apolar medium served to extract alkaloids with the alkalization of the plant samples but with limited performance.