Abstract Ice recrystallization occurring in vegetables during frozen storage causes changes in crystal morphology, and, thus, may affect product microstructure and quality. A mathematical model to describe the evolution of the crystal number density in frozen carrot tissue during dynamically changing temperatures was introduced to get a more comprehensive insight into microstructural changes. The model was based on a population balance equation that incorporated the ice crystal size distribution and a lumped heat transfer model, which assumed ice recrystallization via Ostwald ripening. Ice recrystallization was governed first by the dissolution of small crystals and then by redeposition at the surface of large crystals. This was observed mainly at the beginning of storage and gradually decreased as storage time proceeded. Sensitivity analysis showed that the activation energy is the most important model parameter, followed by the growth and dissolution coefficients. The model was validated based on measurements of the ice crystal size distribution and mean ice crystal size of carrot tissue to describe ice recrystallization during a two-month storage period under dynamically changing temperature condition. The PBE model was then applied to simulate ice recrystallization in carrots under industrial relevant conditions. The simulation results indicate that PBE model may be used to improve storage of frozen vegetables with respect to microstructure and quality.

中文翻译：

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模拟在动态温度条件下储存期间冷冻胡萝卜组织中的冰重结晶

摘要 蔬菜在冷冻贮藏过程中发生的冰重结晶会导致晶体形态发生变化，从而可能影响产品的微观结构和质量。引入了一个数学模型来描述动态变化温度期间冷冻胡萝卜组织中晶体数密度的演变，以更全面地了解微观结构变化。该模型基于包含冰晶尺寸分布和集总传热模型的总体平衡方程，该模型假设冰通过 Ostwald 成熟进行再结晶。冰重结晶首先由小晶体的溶解控制，然后由大晶体表面的再沉积控制。这主要在储存开始时观察到，随着储存时间的进行逐渐减少。敏感性分析表明，活化能是最重要的模型参数，其次是生长系数和溶解系数。该模型基于对胡萝卜组织的冰晶尺寸分布和平均冰晶尺寸的测量进行验证，以描述在动态变化的温度条件下两个月储存期间的冰重结晶。然后应用 PBE 模型来模拟在工业相关条件下胡萝卜中的冰重结晶。模拟结果表明，PBE 模型可用于改善冷冻蔬菜的微观结构和质量的储存。该模型基于对胡萝卜组织的冰晶尺寸分布和平均冰晶尺寸的测量进行验证，以描述在动态变化的温度条件下两个月储存期间的冰重结晶。然后应用 PBE 模型来模拟在工业相关条件下胡萝卜中的冰重结晶。模拟结果表明，PBE 模型可用于改善冷冻蔬菜的微观结构和质量的储存。该模型基于对胡萝卜组织的冰晶尺寸分布和平均冰晶尺寸的测量进行验证，以描述在动态变化的温度条件下两个月储存期间的冰重结晶。然后应用 PBE 模型来模拟在工业相关条件下胡萝卜中的冰重结晶。模拟结果表明，PBE 模型可用于改善冷冻蔬菜的微观结构和质量的储存。