Changes in the Nutrient Composition of Barley Grain (Hordeum vulgare L.) and of Morphological Fractions of Sprouts

Abstract

The objectives of the current study were (1) to evaluate the effect of sprouting on protein, amino acids, fats, fatty acids, starch, total soluble carbohydrates, and ß-D-glucan content of barley grains and (2) to know the content of these nutrients in the morphological fractions of sprouts: green shoot, residual structure of sprouted grain (RSSG), residual structure of sprouted grain plus unsprouted grain (RSSG plus UG), and root fractions and to determine the proportion of each of these fractions (on fresh and dry basis) in the sprout biomass. Barley grain was sprouted in a commercial germination chamber for a period of 6 days. Raw grain was used as a control. Results showed that crude protein, ether extract, total soluble carbohydrates, and cellulose content increased, whereas starch and ß-D-glucan content decreased in sprouted when compared with the control grain. Amino acid and fatty acid profiles were also affected. Thus, aspartic acid, threonine, alanine, valine, isoleucine, lysine, and tryptophan content increased and only that of glutamic acid decreased after sprouting. Regarding fatty acids, an increase in the relative concentration of C18 : 0 and C18:3n-3 and a decrease in that of C18:1n-9 were detected. Partitioning of sprouted barley into three morphological component fractions showed that the residual structures of sprouted grains plus unsprouted grain fraction made up 82.9% and 93.6% of sprout biomass, on fresh and DM basis, respectively, and the remainder was provided by the root fraction, 10.3% and 3.2%, respectively, and by the green shoot fraction, 6.8% and 3.1%, respectively. The three morphological fractions differed in the content of the most analyzed nutrients.