Studies on the characteristic difference of quality betweennew and stored grains in Japonica rice

摘要

Abstract: Changes in the milling quality, chemical characteristics, eating qualityand dynamic viscoelasticities of seven cultivars of japoinica rice after about eightmonths storage at room temperature were studied. Comparisons between new andstored rices showed that no obvious changes in milling quality, amylose and proteincontent were found. Though there was varietal difference, the palatability of allcultivars deteriorated with storage.The overall eating quality of Koshihikari andEtsunan162 stored rice were almost the same as that of new rice of Nihonbare andXiushui11. The deterioration in palatability was due to the deterioration of theappearance, taste and stickiness of cooked rice. New rice grain from cultivars witha good eating quality showed a relatively high palatability as compare with storedrice. The moduli of cooked rice grains of stored rice were increased and values ofloss tangent of cooked rice was lower than those of new rice, such cases in poorpalatability cultivars were much more obvious. The eating quality of stored rice wasgenerally poor for the cultivars with a high free fatty acid content. In addition, thebreakdown and maximum viscosity values in amylographic characteristics wereslightly increased.