Laboratoire d'Energie Solaire, Université de Cocody- Abidjan, 22 BP 582, Abidjan, 22 Côte d'Ivoire.
Laboratoire d'Energie Nouvelle et Renouvelable, Institut National Polytechnique Félix HOUPHOUET - BOIGNY de Yamoussoukro, BP 581, Yamoussoukro, Côte D'Ivoire.
J Food Sci Technol. 2014 Sep;51(9):1711-23. doi: 10.1007/s13197-012-0687-y. Epub 2012 Apr 3.
Sorption isotherms of cassava were determined experimentally using a static gravimetric method at 30, 45 and 60 °C and within the range of 0.10-0.90 water activity. At a constant water activity, equilibrium moisture content decreased with increasing temperature. The equilibrium moisture content increased with increasing water activity at a given temperature. The experimental results were modelled using seven sorption models using non-linear regression technique. Results demonstrated that the GAB model adequately predicted equilibrium moisture content of cassava for the range of temperatures and water activities studied. The thermodynamic functions such as net isosteric heat of sorption, differential entropy of sorption, net integral enthalpy and entropy were evaluated to provide an understanding of the properties of water and energy requirements associated with the sorption behaviour. Net isosteric heat and differential entropy decreased with increasing equilibrium moisture content. The net integral enthalpy decreased while net integral entropy increased with increasing equilibrium moisture content. Net integral entropy was negative in value. All thermodynamic functions were adequately characterised by a power law model. The point of maximum stability was found between 0.053 and 0.154 kg water/kg db for cassava.
采用静态重量法，在 30、45 和 60°C 及水活度 0.10-0.90 范围内，对木薯的吸附等温线进行了实验测定。在恒水活度下，平衡水分含量随温度升高而降低。在给定温度下，随着水活度的增加，平衡水分含量增加。采用非线性回归技术，利用七种吸附模型对实验结果进行了模拟。结果表明，在研究的温度和水活度范围内，GAB 模型能够很好地预测木薯的平衡水分含量。评估了吸附热、吸附微分熵、积分焓和熵等热力学函数，以了解与吸附行为相关的水和能量需求的性质。随着平衡水分含量的增加，净等焓和微分熵降低。随着平衡水分含量的增加，净积分焓降低，净积分熵增加。净积分熵为负值。所有热力学函数都可以用幂律模型很好地描述。在 0.053-0.154kg 水/kg 干物质之间，木薯的最大稳定性点被发现。
