Foam stabilization during processing of starch-based dough systems

- Dough viscosity profiles resulted from simulated processing in a rheometer.
- Shear-thinning promoted the mechanical aeration of starch-based dough.
- High viscosities during fermentation and after heating favored foam stability.
- Fractionated quinoa and rice flour gave best gas retention and bread volume.
- Mechanical aeration increases the bread volume independent from fermentation.

The goal of the study was to identify material properties that (1) facilitate the incorporation of gas into starch-based dough and (2) favor bubble stabilization during all processing stages. A novel rheometer program simulated processing conditions in four consecutive stages with varying shear and temperature profiles. A broad range of viscosities was obtained by various recipe compositions. In consequence, the energy consumption varied during mixing and directly dictated the dough temperature (R2 = 0.98). Rheological data were correlated with the gas volume fraction of doughs (5-25%) and with the bread densities (0.21-0.42 g/ml). Pronounced shear-thinning was more relevant for mechanical aeration (R2 = 0.74) than the absolute dough viscosity. In contrast, during fermentation and baking, high viscosities increased the bread volume (R2 = 0.72) and reduced the mean pore size (R2 = 0.68). In conclusion, valuable new insights were obtained into relevant structures of sensitive cellular food systems, such as gluten-free bread.Industrial relevanceAn extensive variety of novel gluten-free flours and additives is available for the production of bakery products. This makes it difficult to assess and compare the functionality of ingredients. The present paper offers a new method to predict the baking performance of different recipe compositions. This lays the groundwork for an improved understanding of key factors for the production of high quality aerated food structures without a dominating gluten network. Notably, the highest bread volume resulted from a combination of high-speed mechanical aeration with a recipe based on quinoa white flour or refined rice and 2% hydroxypropyl methylcellulose.