粳稻蛋白质与蒸煮食味品质的关系

Effect of Protein Content on Cooking and Eating Quality of Japonica Rice

采用扫描电子显微镜(SEM)和激光共聚焦扫描显微镜(CLSM)对直链淀粉含量相近而蛋白质含量差异较大的水稻籽粒及米饭粒的显微结构进行观察,研究蛋白质与蒸煮食味品质的关系。结果表明:通过感官评价和测定快速黏度分析(RVA)特征谱,确定越光、m90、m119的食味品质随蛋白含量的升高而逐渐降低;SEM、CLSM观察糙米横断面,高蛋白含量的m119的大量蛋白体以近似于蜂窝状包围在复合淀粉粒的周围;CLSM观察浸水籽粒的掰断面,蛋白含量不同的品种的掰断面粗糙度也有区别,蛋白含量越高,掰断面越粗糙,即吸收水分少,反映了蛋白质对大米吸水性的影响;SEM、CLSM观察米饭的显微结构,发现高蛋白品种m119的大量蛋白体包围在复合淀粉粒周围,限制了淀粉的吸水糊化,导致蒸煮食味品质的降低。

The microstructure of raw rice and cooked rice from japonica rice cultivars with similar amylose contents and significantly different protein contents（12.32%,8.42% and 5.72%,respectively）,m 119,m 90 and Koshihikari,was observed under a scanning electron microscope（SEM） and a confocal laser scanning microscope（CLSM） to explore the relationship between protein content and cooking and eating quality.Koshihikari had the best eating quality followed by m90 and m119 as demonstrated by sensory evaluation and rapid viscosity analysis（RVA）.Cross-sectional observations of brown rice under SEM and CLSM showed that compound starch granules in m 119 were surrounded by large amounts of spherical protein bodies in honeycomb-like patterns.The roughness of fracture surfaces of water-soaked brown rice grains increased,and consequently water absorption declined with increasing protein content as observed under CLSM,suggesting that protein content can affect water absorption in rice.The microstructure of cooked rice as observed under SEM and CLSM displayed that water absorption and gelatinization of starch granules were limited because compound starch granules in m 119 were surrounded by large amounts of spherical protein bodies,resulting in deterioration of cooking and eating quality.