直链淀粉含量与稻米品质主要性状及米饭质地关系的研究

以反义Wx基因的转化系及其受体亲本武运粳7号为材料，研究遗传背景相同仅直链淀粉含量不同的4个品系主要品质性状及米饭质地的变化。结果表明：直链淀粉含量不同的4个供试品系的主要品质性状指标与米饭质地指标之间有着明显的差异。直链淀粉含量的降低使得胶稠度变软，粗蛋白含量减少，过低的直链淀粉含量会导致米粒外观呈现蜡质。稻米RVA谱特征和米饭质地明显受到直链淀粉含量的控制，直链淀粉含量明显影响稻米糊化过程中黏度的变化，高直链淀粉品系具有较高的消减值、回复值、热浆黏度及最终黏度，米粉的回生性大，米粉难以糊化，其米饭质地过硬，咀嚼有渣感，无弹性；相反，低直链淀粉含量的品系具有较低的消减值、回复值、热浆黏度及最终黏度，冷却过程中米粉的回生性小，其米饭质地较黏，咀嚼无渣感，有弹性；直链淀粉含量与最高黏度值和崩解值间的关系并非是简单的线性关系，当直链淀粉含量较低时，随着直链淀粉含量的增加，最高黏度和崩解值随之升高，而当直链淀粉含量高于一定量时，直链淀粉的增加会降低最高黏度和崩解值。

Studies on the relationships of amylose content with the grain quality and the texture of cooked rice

This paper reported the relationships of amylose content with the characteristics of RVA profile and the texture of cooked rice in three transgenic rice lines with anti-waxy gene and its original variety Wuyunjing7. The results showed that there were notably difference in the main characters of grain quality and the texture of cooked rice. Gel consistency became soft and the content of coarse protein was reduced while amylose content was decreased. Appearance of the kernel with very low amylose content seemed to be waxy and opaque. The characteristics of RVA profile and the texture of cooked rice were affected significantly by amylose content. The lines with high amylose content had higher setback, consistency, hot viscosity and final viscosity. On the other hand, the texture of cooked rice presented harder and the retrogradation of rice flour was found. In contrary, the lines with low amylose content had lower setback, consistency, hot viscosity and final viscosity, and the texture of cooked rice presented softer. The relations of amylose to breakdown and to peak viscosity were not simple. Speculate that there is a threshold value for the content of amylose. When amylose content was less than the threshold value, breakdown and peak viscosity would increased with the increasing content of amylase, contrarily, they would he reduced.