Effects of mixing conditions and water temperature on viscoelasticity, bubble structure, and quality in gluten-free rice bread

In gluten-free (GF) rice bread, mixing conditions play a critical role in batter structure development, gas retention, and final product quality. We examined the combined effects of mixing arm configuration (flat beater or wire whip), mixing time (3–30 min), and water addition temperature (5°C or 60°C) on the viscoelastic properties, bubble structure, and bread quality of GF rice bread prepared using high-temperature water addition. Batters prepared at 60°C exhibited higher storage and loss moduli than those prepared at 5°C, suggesting enhanced structural development. Increasing the mixing time altered the frequency dependence of viscoelastic moduli and reflected changes in the bubble structure during fermentation and baking. At 5°C, the highest specific volume (2.57 mL/g) was achieved after 30 min mixing using the wire whip. Conversely, at 60°C, the maximum specific volume (2.60 mL/g) with fine and homogeneous bubbles was achieved after 15 min of wire whip mixing. Excessive mixing at 60°C reduced the specific volume and increased the crumb firmness. Hence, both mixing conditions and water temperature influenced batter viscoelasticity and bubble stability, thereby affecting rice bread quality. Remarkably, under the present experimental conditions, 60°C water addition and 15 min wire whip mixing provided a process-based additive-free strategy for achieving high leavening performance with reduced mixing time.