To understand the effect of nitrogen (N) fertilizer on rice (Oryza sativa L.) eating and cooking quality (ECQ). Here, we investigated the ECQ attributes, physicochemical foundation of ECQ, and amylopectin fine structure of two Waxy (Wx) alleles japonica rice cultivars Nanjing 9108 (NJ9108) and Huaidao 5 (HD5) under four N rates (0, 150, 300, and 450 kg ha⁻¹). Sensory and pasting properties of the two cultivars varied depending on N rates. Compared with the control (0 kg ha⁻¹), the overall eating quality and sensory value were significantly decreased under the N rates of 300 and 450 kg ha⁻¹. Further, conventional descriptive analysis showed that the stickiness and retrogradation of cooked rice were significantly decreased. These results indicated that application of N fertilizer seems to affect the texture of cooked rice, causing it to be less sticky, lowering its retrogradation, and consequently reducing its palatability. Results from rapid visco analyzer (RVA) revealed that the peak and breakdown viscosities significantly decreased, while the setback viscosity and peak time increased under the N rates of 300 and 450 kg ha⁻¹. However, no significant difference was observed when the N rate was 150 kg ha⁻¹, indicating that less N fertilization can maintain rice ECQ. As the N rate increasing, protein content increased, whereas apparent amylose content, starch content, and gel consistency almost unchanged. Interestingly, compared with the control, under N treatments, the percentage of short amylopectin branches in NJ9108 was decreased, but increased in HD5, as controlled by amylopectin synthesis-related genes. Notably, SSI and BEIIb were down-regulated in NJ9108, whereas BEIIb was up-regulated in HD5. Thus, the palatability of both rice cultivars was significantly decreased under excessive N fertilization as a consequence of reduced stickiness and retrogradation of the cooked rice, which might have resulted from an elevated protein content and altered amylopectin fine structure. In addition, amylopectin synthesis appeared to be affected by N fertilizer and the genotype of the rice cultivar.

了解氮（N）肥料对水稻（Oryza sativa L.）饮食和烹饪质量（ECQ）的影响。在这里，我们调查了ECQ属性，ECQ的物理化学基础，以及两个的支链淀粉的精细结构糯（蜡质）等位基因粳稻水稻品种南京9108（NJ9108）和坏道5（HD5）下四个N个评分（0，150，300，和450 kg ha ^-1）。两个品种的感官和粘贴特性取决于氮含量。与对照组相比（0 kg ha ^-1），在氮素水平分别为300和450 kg ha ^-1时，总体进食质量和感官价值明显降低。此外，常规描述性分析表明，煮熟的米饭的粘性和回生度显着降低。这些结果表明，氮肥的施用似乎会影响米饭的质地，使其粘度降低，降低其回生度，从而降低其适口性。快速粘度分析仪（RVA）的结果显示，在300和450 kg ha ^-1的N速率下，峰粘度和击穿粘度显着降低，而挫折粘度和峰时间则增加。然而，当氮含量为150 kg ha ^-1时，没有观察到显着差异。，表明较少的氮肥施用可以维持水稻ECQ。随着氮含量的增加，蛋白质含量增加，而直链淀粉含量，淀粉含量和凝胶稠度几乎不变。有趣的是，与对照相比，在N处理下，支链淀粉合成相关基因控制了NJ9108中短支链淀粉分支的百分比降低，而HD5中支链淀粉的分支百分比增加。值得注意的是，SSI和BEIIb被下调NJ9108，而BEIIb在HD5中被上调。因此，由于减少的黏度和煮熟的米饭的回生，这可能是由于蛋白质含量增加和支链淀粉的精细结构改变所致，在过量施氮的情况下，两个水稻品种的适口性均显着降低。此外，支链淀粉的合成似乎受氮肥和水稻品种基因型的影响。