Nutritional value and content of antinutritional compounds and toxics in ten wild legumes of Yucatan Peninsula.
The chemical and toxicological composition was determined of ten wild legumes collected in Yucatan, Mexico. For each species the whole fruit (seeds and pod) was studied as well as the seeds and pods separately. A high protein content was found in the seeds of Albizia lebbeck and Pithecellobium saman [Albizia saman] (37.07 and 37.60%, respectively). In the seeds of Lonchocharpus longistylus, Caesalpinia yucatanensis and Pithecellobium keyense a high concentration of fat was found, especially in the first species, which had 31.34% fat. A high quantity of fibre was found in the pods. In general, the samples were rich in lysine (especially seeds) and scant in sulfur amino acids and tryptophan. All the samples showed high concentrations of potassium and calcium, and some had significant concentrations of iron. The pods of A. saman and P. keyense had a high content of lectins. In the seeds of C. yucatanensis and in the pod of P. keyense high concentrations of trypsin inhibitors were found (60 and 406.7 TIU (trypsin inhibitor units)/mg sample, respectively). Saponins were detected in seven samples, of which the seeds of P. keyense had the highest concentration. Alkaloids were found only in the whole fruit and pod of A. saman, and cyanogenic glucosides were present in Acacia pennatula. In general terms, the whole legume showed better digestibility than the pods alone. The other species tested and not so far mentioned were Acacia gaumeri, Leucaena leucocephala, Senna atomaria and Caesalpinia vesicaria.