优质籼稻储藏期间稻米RVA特性研究

对不同储藏条件下优质籼稻的快速黏度分析（rapid viscosity analysis，RVA）特性进行研究。将含水量为13.5%、14.5%和15.5%的优质籼稻两优234试样，分别在15、20、25、30和35 ℃下模拟储藏720 d，每隔60 d利用快速黏度分析仪测定其相应稻米的RVA特征值并进行分析。结果表明:储藏温度、储藏时间和含水量对稻米RVA特征值有非常显著性影响（P<0.01），其中温度为主要因素。随储藏时间的延长，稻米的峰值黏度和衰减值在储藏前期增加，后期降低。30和35 ℃储藏条件下，稻米的峰值黏度和衰减值在后期明显比其他储藏温度降低更快。最终黏度、回生值、消减值、糊化温度在整个储藏期内增加，高温（30和35 ℃）储藏下的回生值、消减值、糊化温度的变化大于常温、准低温和低温储藏（25、20和15 ℃），充分反映储藏期稻米食味品质的优劣。随着储藏温度的升高和时间的延长稻米食用品质明显下降，储藏温度超过25 ℃劣变加速，可作为稻谷储藏条件参考依据。

RVA Characteristics of High Quality Indica Rice during Storage Period

Under different storage conditions, rapid viscosity analysis (RVA) properties of indica rice were studied. Samples of Liangyou 234 type indica with 13.5%, 14.5% and 15.5% moisture content were chosen to store under 15, 20, 25, 30 and 35 ℃ for 720 d, respectively. RVA eigenvalues of the corresponding rice samples were measured by rapid viscosity analyzer every 60 days. The results showed that the storage temperature, storage time and moisture content of rice had very significant effect on RVA eigenvalues (P<0.01), in which the temperature affected mainly. With the extension of storage time, the peak viscosity and breakdown viscosity of rice increased at the early stage of the storage, and decreased in the late storage period. Moreover, the peak viscosity of rice and breakdown viscosity at 30 and 35 ℃ temperature in late apparently decreased faster than the others. Final viscosity, consistence viscosity, setback value, pasting temperature increased during the storage period, in which these three eigenvalues under the high temperature (30 and 35 ℃) storage were greater than the normal temperature and quasi-low temperature storage (25, 20 and 15 ℃). It reflected the quality of rice eating during storage period. With the increasing of storage temperature and the prolonging of storage time, the edible quality of rice decreased significantly, and the deterioration accelerated when the storage temperature exceeded 25 ℃. It could be used as reference conditions for the control of rice storage.