Investigation of the functionality of macromolecules in the rheological and baking properties of oat milling fractions

Abstract

The aim of this work was to investigate the role of oat constituents in rheological (mixing and pasting) properties and baking performance. To accomplish this, oat milling fractions with different particle size and dietary fibre contents were produced and analysed. Our results showed that with increasing flour particle size, in addition to fibre components, the level of proteins and lipids increased as well, while the digestible carbohydrate content decreased. There were changes also within the fine composition of macro components such as proteins (based on SDS-PAGE), starch (amylose to amylopectin ratio) and β-glucans (molecular weight distribution). With increasing fibre content, dough matrices were characterised by higher water absorption, longer development time, and lower softening, while flour slurries formed more viscous gels. Regarding baking properties of oat milling fractions, it was found that higher fibre content resulted in better crumb structure, supported by images of cross-sections and texture profile analysis. In addition, higher amylose to amylopectin ratio might have contributed to the formation of less resilient crumb structure. Correlation analysis between baking performance and rheological properties showed that doughs with higher water content and lower softening degree, as well as slurries with higher viscosity values resulted in better crumb structure. In conclusion, high-fibre oat milling fractions were found suitable to produce breads with acceptable quality traits. Our work might also contribute to expand our knowledge about the functionality of oat constituents and to develop new, fibre-rich oat-based products supporting the consumption of more dietary fibre.