Dept. of Food Science, Rutgers, The State Univ. of New Jersey, New Brunswick, NJ, 30605, U.S.A.
Dept. of Nutrition, Dietetics, and Food Science, Utah State Univ., Logan, UT, 84322, U.S.A.
J Food Sci. 2019 Nov;84(11):3204-3212. doi: 10.1111/1750-3841.14828. Epub 2019 Oct 7.
Rheological properties of food materials are important as they influence food texture, processing properties, and stability. Rotational rheometry has been widely used for measuring rheological properties. However, the measurements obtained using different geometries and rheometers are generally not compared for precision and accuracy, so it is difficult to compare data across different studies. In this study, nine rheometers from seven laboratories were used to measure the viscosity and viscoelastic properties of a commercial salad dressing. The measurements were obtained at three temperatures (8, 25, and 60 °C) using different diameter parallel plates (20, 40, 50, and 60 mm). Generally, the viscosity measurements among rheometers differed significantly ( ). For larger geometry diameter (40, 50, and 60 mm) and at lower temperatures (8 °C), viscosity measurements at lower shear rate (0.01, 0.1, and 1.0 s ) were significantly different. Rheometer brand significantly affected storage modulus only at low (0.01%) and high levels (10% and 100%) of strain. Temperature was an influencing factor on viscoelastic behaviors only at high strain (>10%). Storage moduli values obtained by frequency sweeps were not affected by rheometer or plate diameter. Overall, rheometer, geometry, and temperature can influence rheological measurements and care should be taken when comparing data across laboratories or published works. Higher shear rates (≥10 s ) and moderate strains (0.1% to 10%) generally provide more repeatable data among different laboratories. PRACTICAL APPLICATION: This study provides information on what factors may potentially influence rheological measurements conducted across different laboratories. It is useful for rheometer users who want to compare their experimental data to published data or compare two sets of published data. It is better to compare data collected at shear rates 10 s and strains between 0.1% and 1.0%.
食品材料的流变性质很重要，因为它们会影响食品的质地、加工性能和稳定性。旋转流变仪已广泛用于测量流变性质。然而，不同几何形状和流变仪获得的测量值通常不进行精度和准确性比较，因此很难在不同研究之间比较数据。在这项研究中，来自七个实验室的九台流变仪用于测量一种商业沙拉酱的粘度和粘弹性。在三个温度（8、25 和 60°C）下，使用不同直径的平行板（20、40、50 和 60mm）测量了粘度和粘弹性。通常，流变仪之间的粘度测量值差异很大（ ）。对于较大的几何直径（40、50 和 60mm）和较低的温度（8°C），较低剪切速率（0.01、0.1 和 1.0s ）下的粘度测量值差异显著。只有在低应变（0.01%和 10%和 100%）和高应变（>10%）下，流变仪品牌才会显著影响储能模量。温度仅在高应变（>10%）下影响粘弹性行为。通过频率扫描获得的存储模量不受流变仪或板直径的影响。总体而言，流变仪、几何形状和温度会影响流变测量值，因此在比较不同实验室或已发表文献的数据时应谨慎。较高的剪切速率（≥10s）和中等应变（0.1%至 10%）通常可在不同实验室之间提供更具重复性的数据。 实际应用：本研究提供了有关可能影响不同实验室进行的流变测量的因素的信息。对于希望将其实验数据与已发表数据进行比较或比较两组已发表数据的流变仪用户非常有用。最好比较在剪切速率为 10s 和应变在 0.1%和 1.0%之间收集的数据。
