[Effect of cooking on the chemical and nutritional value of the Pithecellobium flexicaule (Bent) seed]

The leguminous P. flexicaule grows at the Northeast of Mexico. People living at this region traditionally consume the seeds (unripe cooked or toasted mature). Three localities samples of mature seeds were analyzed. The main results were: Protein (Nx6.25) 35.3%, lipids 25% and total dietary fiber (TDF) 13.2%. After a toasted treatment during 10 minutes (80-90 degrees C), the true protein digestibility increased from 79.3-91.8%, the phytate content and protein inhibitors decreased up to 35 an 96% respectively. Tannin concentration increased from 12.4 to 236 mg eq. cathequine/100 g, probably because during the treatment they passed from the shell to the cotyledons. Unripe seeds gave; protein 12.7%, lipids 6.6%, TDF 3.5%. When the unripe seeds in their sheath were boiling, the true protein digestibility was 85.8% (same value of the raw seeds), phytate content was reduced 68.4% and tannin concentration rose from 4.9 to 226 mg. Due to these results, the seeds free of the shell and sheaths were boiling, this time the tannin and phytate concentration were reduced 73.5 and 88.6% respectively, the true protein digestibility was 94.5%. The sulphur containing amino acids were the limit, as in other leguminous, the protein digestibility corrected amino acid score was 50.6% (unripe seeds), similar to that of pinto beans.