Impact of mixing pressure and temperature on dough and bread properties: A comparison between Verna wheat flour and refined type “0” bread flour

Abstract

This study investigated the combined influence of mixing pressure (atmospheric vs. −0.4 bar vacuum) and temperature (25 °C vs. 5 °C) on the rheology, bread quality and crust morphology of two wheat flours differing in gluten strength: a refined Type “0” flour (W260) and an ancient Verna flour (W150). Doughs were characterized by alveograph tests, texture profile analysis (TPA), and image analysis of crumb and crust structure.

Low temperature mixing improved dough extensibility and swelling in both flours, demonstrating a consistent thermal effect on gluten development. Vacuum mixing selectively increased deformation energy in the strong flour but had negligible effects in Verna, confirming that pressure-based strengthening requires sufficient baseline gluten potential. In refined flour, vacuum mixing enhanced dough strength but reduced loaf height due to decreased gas nuclei, while low temperature promoted better expansion. Weak Verna doughs were largely insensitive to processing changes, remaining genotype bounded.

Overall, vacuum mixing emerged as a conditional lever—effective only above a gluten strength threshold (W ≥ 220–240)—whereas low-temperature mixing proved a robust, flour-independent optimization. These findings define a mechanistic “design rule” linking flour strength to process responsiveness, with practical implications for industrial breadmaking optimization.