Dough rheology properties as affected by the inclusion of oat drink residue flour: A multivariate analysis approach

The global shift towards plant-based food consumption presents significant environmental benefits, yet the consequential rise in related by-products still imposes a challenge to be addressed. The present work was carried out to evaluate the rheological properties of bread dough as affected by the incorporation of dry fractionated oat drink residue flours as a functional ingredient to identify the optimum condition for incorporating fibre-rich ingredients in bakery products. Mechanically dry fractionated, dried oat drink residue flour of particle size F1: > 150, F2: 150-224, and F3: 224-300 μm was blended with strong wheat flour at 10% and 20% substitution levels of the wheat flour. The resulting doughs were assessed for their rheological characteristics. Results from Mixolab, Rapid Visco Analyser, and gel texture properties revealed that 10F3 showed the highest peak viscosity; 20F2 exhibited the highest water absorption value (66.7%), whereas 20F2 showed the lowest gel hardness level compared to control (100% wheat flour). Principal component analysis (PCA) showed that the specific surface area of the flour composite is a key feature determining dough rheological properties. Additionally, cluster analysis results revealed that, within measured parameters, flour pasting properties are the most representative of the flour composite characteristics. Moreover, the analysis was able to discriminate between different flour composites based on their rheological properties. The TOPSIS-Shannon entropy approach was used to increase the inclusion level of non-wheat components in the bread formulations while maintaining the structural quality of the bread. The comparison between different flour composites via TOPSIS analysis revealed that 10F2 was the best formulation in terms of instrumental quality properties of the resultant bread among other flour composites. It was observed that the effect of inclusion level outweighs the effect of particle size distribution on incorporated fibre-rich ingredients in terms of affecting the texture quality characteristics of the resultant bread. Results highlight the potential application of fractionated oat drink residue flour for blending with wheat flour properties to produce fibre-rich bakery products.