Analytical Characterisation of Oat-Enriched Binary Composites of Wheat Flour and Their Processing Behaviour in Bread Making

Le résumé fourni par la source

Oats (Avena sativa L.) are a rich source of β-d-glucans, dietary fibre, proteins, and lipids. However, the behaviour of these components in wheat–oat composite systems during baking, particularly with regard to matrix-dependent analytical responses, remains unclear. This study evaluated the compositional changes, technological performance, and sensory quality of wheat bread enriched with various forms of oat. Composite flours containing 5–15% wholegrain oat flour, commercial oat bran, milled commercial oat flakes, or milled sprouted oat grain (sprouted under laboratory conditions for three days at 25 °C) were prepared using the Slovakian oat cultivar ‘Peter’. The raw materials, flour blends, and baked breads were analysed for β-d-glucans (BG), total dietary fibre (TDF), starch, proteins, and lipids using standardised enzymatic, gravimetric, and polarimetric methods. Bread quality was assessed through loaf volume measurements and a sensory evaluation using a 5-point hedonic scale by seven trained panellists. Multivariate statistical analysis was applied to integrate compositional, technological, and sensory data. Compared to wheat flour (0.24% BG and 3.45% TDF), the incorporation of oats significantly increased the contents of BG, TDF, proteins, and lipids, with oat bran showing the strongest enrichment effect (owing to 15.69% TDF in the raw material). Baking induced oat-form-dependent changes in the measured BG and TDF content. The level of BG diminished in wholegrain oat blends but increased or remained stable in bran-rich systems. This reflects differences in matrix structure and analytical extractability, rather than true compositional gains. Meanwhile, starch content consistently declined across all composite breads. Fibre-rich formulations exhibited reduced loaf volume and altered both bread geometry and morphology, particularly at 15% substitution. Breads containing 5% oat flour or moderate levels of oat bran (5 or 10%) were considered the most acceptable in terms of nutritional enhancement and quality attributes. Germinated oat breads showed the greatest technological impairment and the lowest sensory scores. Overall, moderate oat enrichment strikes a balance between nutritional improvement and technological performance without significantly compromising sensory quality. These findings emphasise the significance of matrix effects when interpreting standard total dietary fibre and β-d-glucans analyses and offer an integrated analytical and technological framework for the rational design of fibre-enriched cereal products.

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