Alkaloid content and taste profile assessed by electronic tongue of Lupinus albus seeds debittered by different methods

Lupin seeds are rich in proteins, lipids and bioactive compounds, but before consumption must be debittered to remove toxic alkaloids. Traditionally, debittering is a water-intensive and protracted process, lasting up to six days. To develop a more efficient procedure, different washing solutions (0.5% and 1% NaCl or citric acid), with or without the use of ultrasound, were applied on Lupinus albus seeds and compared to two control methods, the first with water and the second with a sodium chloride solution. The sonication did not accelerate debittering, while the sodium chloride and citric acid solutions significantly shortened debittering time, reduced water consumption and decreased alkaloid content to commercial values (0.31–1.03 g/kg dry matter). Debittering with a 1% citric acid solution saved 88 h and 65 L water/kg dry lupin compared to the water control method, and 13 h and 31 L water/kg dry lupin compared to the salt solution control method. The electronic tongue grouped the experimental and commercial samples in well-defined clusters; bitter and umami tastes were the main factors, well correlated with alkaloid content. The proposed procedure, either with citric acid or sodium chloride, could be easily adopted by the industry to reduce time and costs of lupin debittering.