Abstract Causal relationships between physical properties and structure/composition of cooked rice are difficult to quantify when mechanical measurements are performed on bulk samples using large deformations that alter the structure irreversibly. We demonstrate here methods involving small-deformation to characterise the elastic modulus (E), adhesion and cohesion at the individual grain level, and show distinct differences between freshly cooked rice and shelf-stable retorted rice. On average, retorted rice is harder and less adhesive and cohesive than freshly cooked rice, but their distributions in each of these mechanical properties overlap. E is independent of adhesion and weakly correlated with moisture content. In addition, a ring-shear tester is shown to distinguish the bulk cohesion and flowing ability between rice samples. Measuring the inherent physical properties of individual grains has the potential to enable a more sensitive evaluation of new processes and grain varieties, and development of quantitative structure-property-processing relationships for rational design of products to perform optimally at different stages, from manufacturing through to oral processing.

中文翻译：

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通过测量单个米粒水平的模量、粘附力和内聚力，对熟米质量的新见解

摘要 当使用大变形不可逆地改变结构对散装样品进行机械测量时，很难量化物理特性与煮熟的米饭的结构/组成之间的因果关系。我们在此展示了涉及小变形的方法，以表征单个谷物水平的弹性模量 (E)、粘附力和内聚力，并显示出新鲜米饭和耐贮存蒸煮米饭之间的明显差异。平均而言，蒸煮米饭比新鲜米饭更硬，粘性和内聚力更小，但它们在这些机械特性中的每一个的分布重叠。E 与附着力无关，与水分含量微弱相关。此外，还显示了环形剪切测试仪可以区分大米样品之间的体积内聚力和流动能力。