Moisture of Foods and Food Models Playing a Role in the Thermal Conduction During Cooking

根据对食物在烹饪过程中的热传导的个案研究的结果，这些类型的工作已经继续进行，以便进一步深入了解水分在各种加热过程中的作用。1)改进了检测加热过程中食品内部温度变化的组件，将测量温度的范围从加热平面扩展到样品中的一维轴至10 mm。2)使用新安装的试验机对食品的机械性能和热性质之间的相互关系进行了初步检查。3)在金属容器中观察了由各种多糖制备的高水分凝胶(大于98wt%)的内部温度。检测到的室内温度上升规律表明t…在所有待测试的凝胶中，更多的是热传导类型。4)以海藻酸钠和玉米油为原料，可制得保湿范围较广(10wt%~82.5wt%)的面团。在蒸煮、煮沸、烘焙、飞行和在金属器皿中加热等不同烹饪方法下，对模型的加热模式进行了比较。所得到的加热模式在所有情况下都可以用指数方程表示，而方程的时间常数与金属容器中飞行和加热情况下模型的热扩散率相关。5)通过脂肪熔化、琼脂凝胶的溶胶化、鸡蛋蛋白的热凝胶化和面团的热膨胀等情况，观察了烹饪过程中组分的相变对食品加热模式的影响。各组分的吸热转变对内部温度的升高有明显的干扰。在发酵粉的存在下，热膨胀现象明显加快了面团的升温速度。较少

According to the results obtained from the case studies on the heat conduction in foods during cooking, these types of works have been continued so as to obtain further insights into the role of moisture in the various heating ptocedures. The contents of the experimental studies and results obtained can be summarized, as follows :1) An assembly for detecting changes in the inside temperature of foods during heating was improved for extending location of the measuring temperature in a range from the heating plane to 10mm along by the one dimensional axis in the sample.2) A preliminary examination was made to obtain informations on the interrelation between the mechanical behaviours and the thermal properties of foods using a testing machine newly installed.3) The inside temperature of the highly moisturized gels (more than 98wt%) prepared with the various polysaccharides was observed during heating in a metal vessel. The examined increasing patterns of the inside temperature indicated t … More he type of thermal conduction in all the gels to be tested. All the patterns could also be expressed by an exponential equation reported before.4) The wheat flour doughs moisturized in a wide range (10wt%〜82.5wt%) could be prepared by mixing Na-alginate and corn oil. The heating patterns of the models were compared with each moisture in different methods of cooking such as steaming, boiling, baking, flying and heating in a metal vessel. The heating pattern obtained could be written by the exponential equation for all the cases, while the time constant of the equation correlated to the thermal diffusivity of the models for the cases of flying and heating in a metal vessel.5) The effect of phase transition of the components on the heating pattern of foods during cooking was observed by some cases, i.e. melting of fats, sol transition of agar gels, thermal gelation of egg proteins, and thermal expansion of wheat flour doughs. The increases of the inside temperature were obviously disturbed by the endothermic transition of each component. The phenomenon of the thermal expansion accelerated pronouncedly the rate of increasing temperature for wheat flour doughs in the presence of the baking powder.. Less