MEASURMENTS OF THERMOPHYSICAL PROPERTIES OF FOOD

测定了豆类的热物理性质，包括导热系数、密度、平衡含水率和干燥特性。影响导热系数：在5个温度(10，20，30，40，50℃)下，测定了不同水分含量(5，10，15，20，25%(W.B))豆类的有效导热系数。将影响导热系数表示为含水率的线性函数。此外，还观察到红豆的温度与温度呈线性关系。热膨胀系数和吸湿膨胀系数：6种含水率(0、5、10、15、20、25%(W.B.)在5个温度(10，20，30，40，50℃)下用比重瓶测量。将测得的密度值换算成干白的比容。利用这些结果，计算了材料的热膨胀系数和吸湿膨胀系数。豆类的平衡含水率(EMC)：用静态法测量豆类的EMC。测定结果符合三个吸附方程：Chen-Clayton方程、修正的Chung-Pfost方程和修正的Henderson方程。小豆的干燥特性：对小豆在25、30、35、40、45℃五种不同温度下进行了薄层干燥试验。因此，根据测量数据得到了干燥速率系数，并将干燥模型描述为无限长圆柱体。

Thermophysical properties of beans, which were effect thermal conductivity, density, equilibrium moisture content, and drying characteristics, were measured.1. Effect thermal conductivity : The effect thermal conductivity of beans in the different moisture contents (5, 10, 15, 20, 25%(w.b)) was measured at five temperatures (10, 20, 30, 40, 50C). The effect thermal conductivity was expressed as a linear function of moisture content. Also, it was observed as a linear function of temperatures for azuki bean.2. Coefficient of thermal and hygroscopic expansion : The density of beans in six moisture contents (0, 5, 10, 15, 20, 25%(w.b.) was measured using pycnometer at five temperatures (10, 20, 30, 40, 50C). The measured values of the density were transformed into the specific volume in the dry baisis. Utilizing these results, coefficient of thermal and hygroscopic expansion were calculated.3. Equilibrium moisture content (EMC) of beans : The EMC of beans was measured by a static method. The measured results were fitted to three sorption equation : the Chen-Clayton, the modified Chung-Pfost, and the modified Henderson equation.4. Drying characteristics of azuki bean : The thin layer drying tests of azuki bean were carried out at five different temperatures (25, 30, 35, 40, 45C). Therefore, the drying rate coefficient were obtained by the measured data, and the drying model was presented as an infinite cylinder.