Effect of Roasting on the Chemical Composition and Protein Quality of Lupin Seeds (Lupinus albus cv Multolupa)

The effect of roasting lupin seeds (Lupinus albus cv Multolupa) for 10, 20, 30, and 40 min at 80–90°C was studied. Raw lupin was shown to be markedly deficient in the S-amino acids. These were not affected by roasting for 10 min, although a mild loss was observed for isoleucine and valine. However, heating for up to 40 min caused important losses in lysine and methionine + cystine. PER for raw lupin was 0.80 (casein 2.93) and that of the 10 min heated sample was 0.92 (NS), while roasting for 20, 30 and 40 min caused a severe reduction in protein quality (PER 0.59, 0.53 and 0.46 respectively). All these values improved significantly (p<0.01) by supplementation with 0.1% DL-methionine. Heating lupin seeds for 10 min may help to remove the “beany” flavor of this legume.