Abstract Moisture sorption isotherms of two fig varieties most grown in Moroccan orchards were assessed simulating the conditions of storage using the gravimetric static method at 30, 40, and 50°C. The equilibrium was reached within 8 to 10 days for desorption and adsorption, respectively over a stepwise increase of relative humidity ranging from 5% to 90%. Experimental data of fig sorption were fitted to three of most used models: GAB, Enderby and Peleg. High-accuracy prediction of the sorption isotherms for “Sarilop” and “Kadota” was obtained with Enderby and Peleg, respectively, since they presented the best adjustment (generally, R² ≥ 0.997 and SE ≤ 1.85). Thermodynamic proprieties revealed a remarkable varietal effect regarding the net isosteric heat, the differential entropy. These differences were probably attributed to chemical composition, structure of the tissues and the intermolecular forces between the sorption sites, water vapor, chemical composition, structure of the tissues and the intermolecular forces. The net isosteric heat of fig samples sorption decreases as the moisture content increased, and was found to be a polynomial function of moisture content for adsorption and desorption. The hysteresis loop was observed among all experiments and its magnitude was remarkable in water activity range of 0.4–0.8. The applied enthalpy-entropy compensation theory to sorption isotherms and plots net isosteric of sorption versus differential entropy provided the isokinetic temperatures, which suggested an enthalpy-controlled sorption process. As a first study of fig thermodynamic proprieties in Morocco, this work aimed to contribute to the fig drying and packaging design and optimization. It also intends to predict moisture changes that might occur during heating process and determine energy requirement for fig drying and shelf life stability.

中文翻译：

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无花果（Ficus carica L.）的吸湿性：水分吸附等温线和等量热动力学的数学模型

摘要 使用重量静态法在 30、40 和 50°C 下模拟储存条件，评估了摩洛哥果园中最常种植的两种无花果品种的水分吸附等温线。在 5% 到 90% 的相对湿度逐步增加的情况下，解吸和吸附分别在 8 到 10 天内达到平衡。无花果吸附的实验数据适用于三个最常用的模型：GAB、Enderby 和 Peleg。“Sarilop”和“Kadota”的吸附等温线的高精度预测分别由 Enderby 和 Peleg 获得，因为它们呈现了最佳调整（通常，R² ≥ 0.997 和 SE ≤ 1.85）。热力学性质揭示了关于净等量热，即微分熵的显着变种效应。这些差异可能归因于化学成分，组织结构和吸附位点之间的分子间作用力、水蒸气、化学成分、组织结构和分子间作用力。无花果样品吸附的净等量热随着水分含量的增加而降低，并且被发现是吸附和解吸水分含量的多项式函数。在所有实验中均观察到滞后回线，其幅度在 0.4-0.8 的水分活度范围内非常显着。将焓-熵补偿理论应用于吸附等温线并绘制吸附的净等量与微分熵提供等速温度，这表明了焓控制的吸附过程。作为摩洛哥无花果热力学特性的首次研究，这项工作旨在为无花果干燥和包装设计和优化做出贡献。它还打算预测加热过程中可能发生的水分变化，并确定无花果干燥和保质期稳定性的能量需求。