Chemical composition, nutritive value, and toxicology evaluation of Mexican wild lupins

The nutrient composition, toxic factors content, and nutritional and toxicological value of Lupinus splendens, L. rotundiflorus, L. elegans, L. simulans, L. exaltatus, L. reflexus, and L. madrensis species from Mexico were analyzed. The seeds of these species were a good source of protein. All the species showed a high lysine and tryptophan content, though sulfur amino acids were limiting. Cyanogenic glycosides were absent, and lectins, trypsin inhibitors, and tannins were present in low concentrations. Lupanine was the major alkaloid in almost all the samples, although sparteine was the major alkaloid in Lupinus reflexus (26.63 mg/g of sample). Cytisine was not found in any of the studied lupins. L. reflexus showed the highest acute toxicity, and L. elegans exhibited no toxicity as evaluated using a mice model. The alkaloid was reduced by hot-water extraction. The protein efficiency ratio in water-debittered seeds was relatively poor (1.1-1.5). These results suggest that the wild lupins studied represent a potential protein supply, and they could be domesticated and used for animal feed if the alkaloids were eliminated and the protein was supplemented with methionine, or if the lupins were used in mixture with cereals.