| Abstract: | The chemical composition and some indices of protein quality were measured in two species of sweet lupine Lupinus albus and Lupinus luteus grown at the Experimental Station in Gorbea, Chile: both samples showed a high protein content (39.5 and 44.6%). The protein efficiency ratio (PER) was measured in the rat and found to be 0.48 and 0.71, respectively, as compared to 2.57 for casein. Supplementation with 0.3% DL-methionine increased significantly those values, thus indicating that lupine protein is deficient in said amino acid. In another experiment the effect of cooking-extrusion on lupine flour (L. albus) was investigated and the chemical composition, protein efficiency ratio, methionine supplementation and digestibility of the protein were measured. The chemical composition was not changed but PER increased from 0.50 for raw lupine to 0.76 for processed lupine (P less than 0.05). Both values increased significantly with the addition of 0.3% DL-methionine. The protein digestibility of the supplemented lupine was not affected by the cooking extrusion process (76.5 and 77.8%, respectively). Supplementation of wheat flour with 5, 10, 15 and 20% lupine flour increased the PER of wheat flour from 0.92, to 1.39 for wheat flour supplemented with 10% lupine flour, and to 1.60 for the 15% level of the supplement. These studies seem to support the conclusion that sweet lupine is an interesting protein resource for human nutrition. |
