米粉稻籽粒直链淀粉积累特性

【目的】稻米中直链淀粉含量是影响米粉品质的重要因素,较高直链淀粉含量的稻米加工的米粉结构坚固,可以减少米粉的蒸煮损失,探索米粉稻籽粒直链淀粉积累特性为调控米粉稻直链淀粉含量和提高米粉稻品质提供理论依据。

Amylose Accumulation Properties in the Grains of Noodle Rice

【Objective】Amylose content in rice grain is a key factor affecting the quality of rice noodle. Rice noodles processed from rice with higher amylose content have a strong structure, which can reduce the cooking loss of rice noodle. It is important to regulate the amylose content and quality of noodle rice by ascertaining the amylose accumulation property of noodle rice grain. 【Method】Using two high amylose content noodle rice varieties (Luliangyou 996 and Zhongjiazao 17) and two low amylose content rice varieties (Lingliangyou 268 and Xiangzaoxian 45 as control) as materials, the field experiments were conducted in early and late season in 2016 and 2017. The grain-filling properties and amylose accumulation properties were analyzed based on the Logistic equation. 【Result】The amylose content in noodle rice variety was 44.8%-72.3% significant higher in noodle rice than that of control variety. The amylose accumulation in noodle rice showed 61.2%-92.8%, 60.0%-91.1%, 61.2%-92.3%, and 59.3%-89.3% higher than that in control variety during the gradual increase phase, rapid phase, slow increase phase, and the maximum accumulation rate phase, respectively. In the same planting season, the average rate of amylose accumulation, the accumulation rate during the increasing period and the maximum accumulation rate of noodle rice were 36.7%-91.2%, 40.2%-58.3%, and 29.2%-108.7% higher than that of control variety, respectively. And the duration of the gradual increase period was 0.6-2.8 d longer than the control variety, and the maximum amylose accumulation rate start-up time was 1.4-2.9 d later than that of control variety. The contribution of amylose accumulation in gradual, rapid, and slowly increase period of amylose accumulation duration to total amylose accumulation were relatively stable with different rice varieties growing in different seasons, with the value of 21.03%-21.32%, 57.58%-57.88%, and 11.38%-14.62%, respectively. Grain amylose accumulation was accompanied by the grain filling process, and the gradual, rapid, and slowly increase phase of grain filing dry matter accumulation occurred 0.1-4.9 d earlier than that of the corresponding amylose accumulation. Meanwhile, the grain filling period, maximum filling rate start time and filling duration of noodle rice were on average 0.1-1.8 d, 1.2-2.0 d and 1.2-3.6 d longer or later than that of control variety. The mean temperature and incident radiation during the 5 days after flowering in early season of 2016 were 30.1℃ and 21.1 MJ·m^-2, which showed 5.1℃-6.3℃ and 2.0-19.1 MJ·m^-2 higher than the other three seasons of the same growing period; while the grain-filling and amylose accumulation duration reduced 6.2-11.5 d and 9.0-13.9 d in the early season in 2016 than the other three seasons, respectively, and the grain-filling rate and amylose accumulation rate was increased by 53.9%-73.7% and 57.4%-67.9%, respectively. 【Conclusion】Higher temperature and incident radiation in the early stage of grain-filling could reduce the duration of grain-filling and amylose accumulation, and improve the grain-filling rate and amylose accumulation rate. The longer duration of gradual period with grain-filling and amylose accumulation as well as the higher amylose accumulation rate in gradual period in rice grain were the basics of high amylose content in noodle rice. The longer grain-filling duration, the higher amylose accumulation rate, the later happened time of the maximum amylose accumulation and grain-filling rate were benefit to amylose accumulation in grain of noodle rice.