Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-8572, Japan.
Faculty of Agriculture, Fukushima University, Fukushima, Fukushima, 960-1296, Japan.
J Food Sci. 2020 Dec;85(12):4327-4334. doi: 10.1111/1750-3841.15452. Epub 2020 Nov 6.
In this study, the bubbles in rice flour batter were investigated under a constant temperature, because the bubble size distribution is important for the control of food texture. We obtained experimental data using a hand mixer and compared the properties of doughs prepared using six rice flours; each flour was prepared through a different milling process. We also added the size effect of the rice flour particles as the Bond number. Furthermore, we performed a dynamic wettability test to estimate the wettability of the rice flour surface. The results of this test were described well by the Washburn equation, and d cosθ/d was calculated as a wettability parameter (where, d = effective diameter of a capillary in a powder bed, cosθ = the contact angle, d = mean particle diameter of rice flour). If bubble sizes depend mainly on the inertial force, viscous force, surface tension, and gravity, then the normalized mean bubble diameter should be a function of the Reynolds number, Weber number, and Froude number. The mean bubble diameter (d ) generated by whipping was expected to be affected by the thickness (d) of the rod of the mixer, its movement speed, and physical properties of the material. Therefore, dimensionless mean diameter (d /d) was expressed based on a dimensionless equation. In the three-phase dispersion, different empirical equations were obtained depending on the amount of rice flour added, and the bubble diameter could be predicted using dimensionless parameters. In addition, the equations were generally applicable to the various materials selected for this study. PRACTICAL APPLICATION: The powder properties of rice flour were investigated, and dimensionless parameters were analyzed to construct an appropriate process control system for rice flour-based food products. Although the process method optimized for flour products is also used for rice flour products in practical situations, the comprehensive evaluation based on dimensionless parameters leads to optimization of the process for rice-flour based products. Moreover, this optimization might strongly support the creation of a new texture, and thus, the potential for market expansion of rice-flour based products is considerable.
在这项研究中，我们在恒温条件下研究了米粉面糊中的气泡，因为气泡大小分布对于控制食品质地非常重要。我们使用手动搅拌器获得了实验数据，并比较了使用六种米粉制备的面团的性质；每种面粉都是通过不同的研磨工艺制备的。我们还添加了米粉颗粒的大小效应作为邦德数。此外，我们进行了动态润湿性测试，以估计米粉表面的润湿性。该测试的结果很好地由 Washburn 方程描述，并且计算了 d cosθ/d 作为润湿性参数（其中，d = 粉末床中毛细管的有效直径，cosθ =接触角，d = 米粉的平均粒径）。如果气泡大小主要取决于惯性力、粘性力、表面张力和重力，那么归一化平均气泡直径应该是雷诺数、韦伯数和弗劳德数的函数。通过搅拌产生的平均气泡直径（d）预计会受到搅拌棒厚度（d）、其运动速度和材料物理性质的影响。因此，基于无量纲方程表示了无量纲平均直径（d/d）。在三相分散中，根据添加的米粉量获得了不同的经验方程，并且可以使用无量纲参数预测气泡直径。此外，这些方程通常适用于本研究中选择的各种材料。实际应用：研究了米粉的粉末性质，并分析了无量纲参数，以构建适合基于米粉的食品产品的适当过程控制系统。虽然针对面粉产品优化的工艺方法也用于实际情况下的米粉产品，但基于无量纲参数的综合评估导致了针对米粉产品的工艺优化。此外，这种优化可能会强烈支持新质地的创造，因此，基于米粉的产品的市场扩展潜力是相当可观的。
