Water Binding Capacity of Rye Flours with the Addition of Native and Modified Arabinoxylan Preparations

Abstract

Despite a highly beneficial role of water soluble arabinoxylans, the information about the effect of their addition on the properties of rye dough is lacking. The aim of this study was to check the influence of their modification methods and properties on water binding capacity of rye flour and suggest some possible explanations for the action of various fractions of arabinoxylans. Three modifications of isolated arabinoxylans were carried out: enzymatic hydrolysis, cross-linking, and combination of both. The preparations used as additives differed in molecular characteristics of arabinoxylans, as well as their rheological behavior. The addition of all preparations at 1 and 2% levels to rye flour types 720 and 1,150 resulted in an increase of water absorption. The high water absorption of the two rye flour types with the same amount of arabinoxylan preparations was mainly related to structural properties of arabinoxylans, such as molecular mass and substitution ratio. Structural properties were responsible for rheological behavior of the samples, which allow prediction of the final water absorption of rye flour. Keywords: Arabinoxylans, Cross-linking, Dough, Xylanase hydrolysis.