The interactive effects of roasting degree and lipid content on the gas retention capacity in fermented oat dough

Roasting effectively inactivates lipase and inhibits lipid oxidation, thereby enhancing the storage stability of oat flour. However, the synergistic effects of roasting degree and lipid content on the gas retention properties of oat dough remain unclear. This study systematically investigated these interactions using oat flours with varying roasting degrees (R0, R1, and R2) and lipid contents. Results demonstrated that the dough gas retention was primarily governed by a significant interaction between the two factors (p < 0.01). This interaction revealed that a functional transition of endogenous lipids, which shifted from foam destabilizers in unroasted (R0) dough, to positive contributors under light roasting (R1), with this benefit diminishing in highly roasted (R2) systems. As the dominant factor, roasting reduced dough stickiness (from 72.2 g-114.4 g to 18.7 g-24.7 g) and enhanced the surface tension and apparent viscosity of the dough liquor. These changes drove the transformation of the foam microstructure from a heterogeneous (0 μm-800 μm) to a uniformly dense (0 μm-180 μm) state, which in turn stabilized the gas cells. Overall, these findings demonstrate that lipids functionality is not intrinsic but is determined by roasting-induced structural changes in the dough matrix. This study provides a fundamental basis for optimizing processing parameters for oat-based products.