Influence of Genotype and Environment on Arabinoxylan Content and Structural Characteristics in Grain and Flour of Organically Grown Winter Rye

The aim of the study was to determine the effects of environmental factors (harvest year and growing location), genotype, and their interactions on the content, molar mass, degree of arabinose substitution, and ferulic acid content of arabinoxylans (AXs) in organically grown rye grain and the corresponding low-extraction rye flours. The experimental material consisted of grain from five population cultivars and two hybrid rye cultivars. Genotype, harvest year, growing location, and their interactions affected most of the analyzed arabinoxylan characteristics, although the significance and magnitude of these effects depended on the arabinoxylan fraction and material analyzed. Rye grain was characterized by a higher total AXs content but a lower proportion of the water-extractable fraction compared with the flour. The molar mass of water-extractable AXs ranged from 1.53 × 106 to 2.79 × 106 g/mol in rye grain and was lower in flour (1.27 × 106–2.35 × 106 g/mol), indicating that the high-molar-mass AXs are predominantly localized in the outer layers of the grain. For the first time, it was observed that in the whole grain high-molar-mass AX molecules are less substituted with ferulic acid than AXs of low molar mass. This association may contribute to a better understanding of the structural characteristics of rye cell wall polysaccharides and could provide useful preliminary information for rye breeding and the development of rye-based foods with desirable technological and nutritional properties.