长江下游地区部分优质粳稻品种与越光稻米支链淀粉结构特征及品质性状比较

Differences in Amylopectin Structure and Grain Quality of Rice Between Some High-Quality Japonica Cultivars from the Lower Yangtze River Region,China and Koshihikari from Niigata,Japan

为探讨具有优异食味品质的日本粳稻品种越光与中国长江下游地区食味品质好的水稻品种稻米的支链淀粉链长分布和主要品质特征差异,以期为中国优质水稻育种提供理论依据,选用长江下游地区公认的食味品质好的5个粳型水稻品种稻米和日本新泻地区生产的越光稻米为材料,分析支链淀粉链长分布、稻米RVA谱、直链淀粉含量、蛋白质含量、TOYO味度值等主要品质特性的差异及其相关性。越光的稻米支链淀粉链长分布和直链淀粉含量等主要品质指标与长江下游地区食味品质好的品种没有明显差异,支链淀粉长链部分(Fb3)和蛋白质含量显著低于长江下游地区食味品质好的品种,支链淀粉短/长链比(Fa/Fb3)显著高于长江下游地区食味品质好的品种。越光稻米中Mg、K含量以及淀粉谱特性中最高黏度、崩解值均显著高于长江下游地区食味品质好的品种。支链淀粉的短链部分(5≤DP≤12)所占比率与最高黏度值和崩解值呈显著正相关,Fa/Fb3与最高黏度和崩解值均呈显著正相关。由此认为,通过育种手段改善稻米的支链淀粉理化特性,并在栽培措施上通过降低氮肥施用量来降低稻米中蛋白质含量,是提高长江下游地区水稻品种食味品质的有效途径。

Amylopectin chain length distribution,RVA profile value,amylose content,protein content,TOYO palatability and other quality characteristics of rice flour were compared between japonica rice cultivar Koshihikari （produced in Niigata,Japan） and five japonica rice cultivars well known as good eating quality from the Lower Yangtze River Region,China.The Koshihikari rice had no significant difference with japonica rice from the Lower Yangtze River Region in amylopectin chain length distribution and amylose content,whereas the Japanese rice possessed significantly lower proportion of long chain Fb3 [37≤Degree of polymerization （DP）≤58] and protein content and a significantly higher ratio of short and long chain（Fa/Fb3） than japonica rice from the Lower Yangtze River Region.Moreover,the Koshihikari rice possessed significantly higher values in Mg and K contents,peak viscosity and breakdown viscosity than those of rice from the Lower Yangtze River Region.There was a significantly positive correlation between the proportion of short chain Fa（5≤DP≤12） and the characteristics of RVA profile,such as peak viscosity and breakdown,and a significantly positive correlation between the ratio of short and long chains（Fa/Fb3） and RVA profile characteristics,such as peak viscosity and breakdown.Therefore,it is concluded that improving structure characteristics of amylopectin in breeding and reducing nitrogen fertilizer in cultivation are the most efficient approach for improving rice palatability in the Lower Yangtze River Region of China.