Molecular properties of arabinoxylan fractions isolated from rye grain of different quality

• Structural properties of arabinoxylans (AX) in rye kernels dependent on their size.
• AX, contained to 2.3-2.7% in well developed kernels, is small and least branched.
• Water absorption of flour is related to water extractable high molecular mass AX.

Content, structure and molecular dimensions of arabinoxylan in rye grains influence dramatically the bakery process and the quality of products. Under this aspect, relationships between rye grain quality and properties of arabinoxylan fractions are very important. For detailed information about molecular characteristics, water extractable (WEAX) and water unextractable (WUAX) arabinoxylan fractions from three different varieties of rye during 3 seasons were investigated. Moreover, our research focused on establishing relations of grain quality, indicated by mass of 1000 kernels, to quantity and structure of arabinoxylans. These results help to predict water binding capacity of rye flour in relation to grain quality.Structural features of AX present in rye kernels depended on their size, affected by environmental conditions in the seasons. During the first season, WEAX, present in well developed kernels in amounts of 2.3–2.7%, were the least branched with the smallest molar mass. WEAX from the last season were highly branched, exhibiting high molar mass. In case of WUAX, an influence of seasons could only be observed for the molar mass, following the same trend as in the case of WEAX. The presence of large and highly branched WEAX molecules was accompanied with significant values of water binding capacity of rye flour.