Flaxseed oil cake as a functional ingredient of gluten-free bread: impact on antioxidant properties, volatile organic compounds, and bioaccessibility of minerals.

Gluten-free bread (GFB) often exhibits nutritional imbalances compared with conventional wheat-based bread. Flaxseed oil cake (FOC) is a nutrient-rich by-product containing minerals and bioactive compounds with antioxidant properties. This study evaluated the effects of FOC incorporation into GFB formulations on antioxidant properties, the volatile organic compound (VOCs) profile, and mineral bioaccessibility. The increase in FOC in the GFB formulation was accompanied by a significant (p ≤ 0.05) increase in total phenolic content and the enhancement of the antioxidant potential. Its incorporation also markedly increased total mineral content, although the effect on in vitro bioaccessibility depended on the mineral. FOC incorporation at 5% increased the relative VOC content, while this effect was not observed at 15% and 30% FOC additions. Overall, these findings support the potential of FOC as a value-added ingredient for GFB while contributing to the valorisation of an agri-food by-product.