Chemical composition and carbohydrate content of seeds from several lupin species

Abstract

The chemical composition of mature whole seeds of six cultivars of yellow lupin (Lupinus luteus L.), three cultivars of white lupin (Lupinus albus L.) and two cultivars of narrow-leaved lupin (Lupinus angustifolius L.) was determined with particular attention to the content of α-galactosides and non-starch polysaccharides. α-Galactoside contents significantly differed among lupins, averaging (per kg DM) 105, 85 and 60 g in yellow, white and narrow-leaved lupins, respectively. Stachyose was the dominant α-galactoside; its level in seeds of yellow and white lupins was similar (about 60 g) and significantly higher than in seeds of narrow-leaved lupins (about 33 g). Opposite proportions of the minor α-galactosides, galactopinitol, digalactopinitol and digalactoinositol, were observed. The highest proportion of verbascose was found in the seeds of yellow lupins. Yellow lupins seeds contained significantly less non-starch polysaccharides (321 g) than other lupins (about 400 g). Glucose and galactose constituted the main part of NSP sugar residues (from 31 to 43% and from 31 to 32%, respectively). Considerable differences among species were found in the contents of rhamnose, xylose, galactose and uronic acids.