稻谷腹部、背部微观结构差异性分析

【目的】从微观角度对糙米腹部、背部的结构差异性进行研究,从宏观角度对糙米的三点弯曲破碎力学性能进行研究,以建立微观结构与宏观力学性能之间的相关关系,为稻谷籽粒裂纹起始于腹部建立理论依据。【方法】对两个品种糙米横截面的腹部、背部在淀粉粒和细胞层次以及糊粉层进行扫描电镜观察,采用三点弯曲法测试糙米的破碎力学性能。【结果】糙米腹部、背部微观结构在淀粉粒、细胞层次以及糊粉层均存在差异,籽粒腹部、背部微观结构的差异对其腹部、背部的结构强度产生影响,使籽粒腹部的结构强度小于背部,与力学测试性能一致,并且腹部、背部微观断裂形式亦存在差异。【结论】稻谷籽粒在解吸和吸湿条件下裂纹起始于腹部与其腹部结构强度小于背部有关。

Analysis on Microstructure Difference of Ventral and Dorsal Side of Rice Grain

【Objective】 Microstructure difference of rice between ventral side and dorsal side was researched, and the mechanical property difference with three-point breaking force between ventral side and dorsal side were also researched. Correlation between mechanical property and microstructure of rice was established, thus providing a theoretical basis for rice fissure appearance from dorsal side of rice grain. 【Method】 Ventral and dorsal side of two rice varieties at starch granule, cell and aleurone stratum levels were investigated under scanning electron microscope. Mechanical property of rice was tested by three-point breaking force. 【Result】 The microstructure of rice on ventral and dorsal side is different at starch granule, cell and aleurone stratum levels. Microstructure difference of rice on ventral and dorsal side affects structure strength and mechanical properties of rice between ventral and dorsal side. And the structure strength in ventral side is lower than that in dorsal side. These accord with mechanical property. Fracture form in microstructure is also different on ventral and dorsal side. 【Conclusion】 Rice fissure that started from the ventral side is related with structure strength of ventral side will be lower than that of dorsal side under desorption and absorption condition.