粳稻品种新米和储藏米品质性状的比较研究

本文以常温下储藏8个月的7个粳稻品种糙米和相应的新米为研究材料，比较分析了加工和营养品质、稻米淀粉粘滞特性（Viscosity）、食味品质、游离脂肪酸含量及米饭质地的动态粘弹性（Dynamic viscoelas-ticities）。结果表明：短期储藏对粳稻直链淀粉、蛋白质含量和加工品质没有明显影响；储藏米食味普遍比其相应的新米要差，但新米食味好的品种其储藏米也相对较优，储藏米的综合食味评价值与新米一样和米饭外观、滋味、粘性有很高的正相关；粘度谱的衰减值和峰值粘度有所上升；米饭质地的粘弹性和动态损失正切值（Loss tangent）分别比新米上升21．47％和下降26．76％；粳稻储蓄米游离脂肪酸含量的增加是导致食味变差的主要原因，这在食味相对较差的品种中尤为明显。通过米饭质地动态粘弹性和游离脂肪酸含量的测定可以评价储藏米的食味特性。

Characteristic Comparision between New and Stored Grains of Japonica rice (Short Grain Rice)

Changes in the milling quality, chemical characteristics, eating quality and dynamic viscoelaosticities of seven cultivars of Japonica rice (short grain rice) after about eight months storage at room temperature were studied. Comparisons between new and stored rices showed that no obvious changes in milling quality, amylose content and protein content were found. The palatability of all cultivars deteriorated with storage. The overall eating quality of Koshihikari and Et-sunan162 stored rice were almost the same as that of new rice of Nihonbare and Xiushuill. The deterioration in palatability was due to the deterioration of appearance, taste and stickiness of cooked rice. Cultivars with a good eating quality showed a relatively high palatability of stored rice. The moduli of cooked rice grains of stored rice were higher and values of loss tangent were lower than those of new rice. Such cases in poor palatability cultivars were much more obvious. The poor eating quality of stored rice was mainly caused by increase of free fatty acid content during storage. In addition, the breakdown and maximum viscosity values in amylographic characteristics were slightly increased with storage.