Environmental Factors Which Cause Heat Damaged Rice Grain in Silo and Their Mechanisms

稻谷是一种生物，在环境因素的作用下，萌发和代谢是活跃的。从物理上讲，大块谷物可以看作是一种隔热材料。由单层钢板组成的简单圆柱形仓，其中储存的谷物充当隔热层，最近得到了推广。如果在正常的环境和气候下不小心使用，这些仓很容易造成热损米粒。热损米是指意外发酵的大米。它有一种像堆肥的气味，当它还是湿的和新鲜的，不能食用。热损伤糙米的外观颜色变为深褐色，精米的外观颜色从棕色变为粉红色。造成水稻热损的机理有：(1)筒仓内形成热点或湿点。这可能是由于雨水泄漏，或露水凝结在垃圾桶的内侧。凝结发生在物体的层和表面。像老鼠和昆虫这样的小动物更可能是热源。(3)微生物在热点及其周围扩散生长。(4)颗粒的导热系数很低，不能分散现场产生的热量。(4)现场变得更热、更湿，导致谷物发芽。还有霉菌等微生物的生长扩散。(5)热点的热量和水分，加上生物的新陈代谢，造成筒仓发酵破坏的恶性循环。(6)因此，热点引导筒仓发酵，形成发酵或热损大米。一般来说，技术控制点已经多次公布。最重要的技能是控制温度和水（空气和粮食）。操作人员应通过观察粮食温度来控制储存系统，发现热点的形成。如果发生了，应该快速旋转。防止漏水和雨滴也很重要。发酵破坏在寒冷地区和湿热地区都有发生，但形式不同。少

Rice grain is a living thing which germinates and metabolizes actively if the environmental factors meet with. Physically speaking, bulk grain can be looked upon as a thermal insulator. Simple cylindrical bins composed by a single layer steel panel in which the stored grain acts as a thermal insulator have been popularized recently. These bins easily cause heat damaged rice grain if they were used carelessly under a normal circumstances and climates. Heat damaged rice is defined as the rice fermented by accidents. It has an odour like compost when it were still wet and fresh, and inedible. The external color of the heat damaged brown rice changed to dark brownish, and of milled rice, varies from brown to pink.The mechanisms causing heat damaged rice are ; (1) Formation of hot or wet spot in a silo. It may be by leakage of rain water, or condensation of dew at the inner side of the bin. Condensation occures in the layer and the surface of bulk. (2) Small animals as rats and insects can … More be heat sources. (3) Growth of microorganisms spreads in and surroundings of the hot spot. (4) Very low thermal conductivity of grain does not disperse the heat generated in the spot. (4) The spot becomes hotter and wetter causing the germination of the grain. Also the growth of microorganisms such as mold spreads. (5) Heat and water from the hot spots, and metabolism of living things cause a vicious cycle of in silo fermentatuion damage. (6) Thus the hot spots lead the fermentation in silo and as the results, fermentated or heat damaged rice will be formed.Generally speaking, the technical control points are already announced repeatedly. The most important skill is the control of temperature and water (of air and grain). Operator should control storage system by watching grain temperature to find the formation of hot spot . and if it occures, quick rotation should be applied. Pevention of water leakage and of rain drop are also important.Fermantation damage occures both in cold areas and in hot- humid areas, but in different styles. Less