GERMINATION ALTERS THE CHEMICAL-COMPOSITION AND PROTEIN-QUALITY OF LUPIN SEEDS

The chemical composition and protein quality of the kernels from Lupinus angustifolius seeds were compared with that for sprouts after 6 days germination. Germination resulted in an apparent increase in protein content from 395 g kg-1 to 435 g kg-1 DM. Fat and carbohydrate contents decreased. The oligosaccharide content of the sprouted lupin fell to a negligible level, while the phytate and alkaloid concentrations fell from 4.7 g kg-1 to 1.6 g kg-1 and from 0.72 g kg-1 to 0.16 g kg-1, respectively. The quality of lupin kernel protein was poor with a protein efficiency ratio (PER) of 1.45 +/- 0.15. Supplementation of kernel with DL-methionine (2-0 g kg-1) increased the protein quality (PER = 2-87 +/- 0.17) to that of casein (PER = 2.86 +/- 0.18). Germination reduced protein quality (PER = 0-44 +/- 0.16), and did not improve apparent protein digestibility (APD kernel = 80 +/- 4%; APD sprout = 77 +/- 5 %). Supplementation of sprout protein with DL-methionine (2.0 g kg-1) increased the protein quality (PER = 2.57 +/- 0.20). The total sulphur-containing amino acid concentration of lupin kernel protein, 1-9 g per 16 g N was low, and decreased further to 1.3 g per 16 g N in the sprout, a drop of 32 %. The results showed that germination of lupin seeds reduced the concentration of the anti-nutritive factors; however, it also reduced protein quality.