Abstract An accurate understanding of the dehydration kinetics of biological materials is essential to optimize their dehydration processes and to produce high-quality dried products. For a soft, cellular material like fruit, the underlying mass transport and deformation mechanisms at the cellular scale play a key role here. To improve our insight into the cellular scale dehydration kinetics, a 3D model is developed to quantify the impact of the changes in the cellular structure of apple (parenchyma) cells during dehydration on the tissue sorption isotherm and water permeability. As a step beyond the current state-of-the-art models, the model incorporates the changes in the cellular structure over entire dehydration process, starting from a turgid cell down to the occurrence of (free) shrinkage, plasmolysis (detachment of the cell membrane from the cell wall) or lysis (rupture of the cell membrane). Regarding the tissue sorption isotherm, plasmolysis induced a reduction in the equilibrium water content (up to 60%) compared to the free-shrinkage or lysis cases at the same water activity level. On the other hand, the tissue water permeability was found to increase up to five times when lysis occurs, compared to free shrinkage or plasmolysis. A parametric study also quantified the dependency of tissue permeability on the cell wall thickness, the cell membrane permeability, the cell size and the elongation aspect ratio of the cell. We identified that the dehydrated, shrunken cellular tissue reduces the outgoing water flux compared to fresh tissue for the same water potential gradient. As such, dehydrated tissue forms a barrier against further moisture removal from the fresh tissue below.

中文翻译：

---

通过 3D 连续介质建模对细胞尺度苹果果实脱水过程的新见解

摘要 准确了解生物材料的脱水动力学对于优化其脱水过程和生产高质量的干燥产品至关重要。对于像水果这样柔软的细胞材料，细胞尺度的潜在质量传输和变形机制在这里起着关键作用。为了提高我们对细胞尺度脱水动力学的了解，开发了一个 3D 模型来量化脱水过程中苹果（薄壁组织）细胞的细胞结构变化对组织吸附等温线和水渗透性的影响。作为超越当前最先进模型的一步，该模型结合了整个脱水过程中细胞结构的变化，从膨胀的细胞到（自由）收缩的发生，质壁分离（细胞膜与细胞壁分离）或裂解（细胞膜破裂）。关于组织吸附等温线，与相同水分活度水平下的自由收缩或裂解情况相比，质壁分离导致平衡水含量降低（最多 60%）。另一方面，与自由收缩或质壁分离相比，发现发生裂解时组织水渗透性增加了五倍。一项参数研究还量化了组织通透性对细胞壁厚度、细胞膜通透性、细胞大小和细胞伸长纵横比的依赖性。我们发现，在相同的水势梯度下，与新鲜组织相比，脱水、收缩的细胞组织减少了流出的水通量。因此，