Study on the Transport Phenomena and Quality Determination of Agiricultural Products Based on Noueguilibrium Thermodynamics

根据吸附能威布尔分布函数导出Dubinin-Astakhov （DA）方程的近似方法，尝试对低水分食品的吸水率进行统计处理。从理论上改变了这三个参数的含义，推导出了一个适用于食品的修正DA方程。利用修正的DA方程，给出了水稻平衡水分含量方程的新表达式。食物中水和糖类之间的相互作用非常重要。通过解点下降法测定了糖-水体系的水活度系数。葡萄糖-水体系是理想的溶液。这些体系的凝固点下降与摩尔分数成正比，并证实了实验数据的准确性。麦芽糖-水体系表现为理想的溶液。在两种体系中，蔗糖-水体系的水活度系数从摩尔分数1.0下降到0.02以上。采用静态法，在10℃的温度下获得了结晶糖和玉米淀粉的吸附数据。在每个饱和点以下的水活度下，每个结晶糖吸收的水可以忽略不计。蔗糖的无定形数据在用蔗糖-水溶液曲线展开的光滑曲线上。在水活度从0到饱和点范围内，DA方程与非晶态数据吻合较好。结果表明，DA方程也可以成功地应用于无孔食品。基于上述高湿食品的吸水性和非平衡热力学，导出了蔬菜水分运动系数的方程。通过方程中的摩擦系数来讨论蔬菜的品质。此外，还推导出了水在低水分食物中的扩散系数的近似阿伦尼乌斯方程。活化能表示为温度和含水率的函数。

The attempt at a statistical treatment of water sorption by foods of low moisturre content was made, based on the approximate method for deriving the Dubinin-Astakhov (DA) equation from Weibull distribution function of adsorption energies. A modified DA equation suitable for foods was also derived by changing the meaning of the three parameters theoretically. A new expression of equilibrium moisture content equation for rice was shown by the use of modified DA equation.Interactions between water and saccharide in food are very important. The Water activity cefficient in saccharide-water systems was measured by freesing point depression. Glucose-water systems were used, being ideal solutions. Freezing point depression in these systems was proportional to mole fraction and the accuracy of the experimental data was confirmed. Maltose-water systems behaved as ideal solutions. For tow systems, water activity coefficient decreased from 1.0 at mole fractions above 0.02 in sucrose-water systems.Sorption data of crystalline saccharides and a corn starch were obtained using static method at 10 ﾟC.Each crystalline saccharide sorbed a negligible amount of water at water activity below each saturation point. Amorphous data of sucrose were on the smooth curve expolarated by the sucrose-water solution curve. DA equation showed good agreement with the amorphous data in the range of water activity from 0 to saturation point. As a result, it was shown that DA equation is also applied successfully to the non-porous foods.Based on the above-mentioned water sorption of highly moistened food and nonequilibrium thermodynamics, an equation was derived for the water movement coefficient in vegetable. the quality of vegetable was discussed by the friction coefficient inside this equation. A modefied Arrhenius-type equation was also derived for the diffusivity of water in low moistened food. the activation energy was expressed as a function of temperature and moisture content.