†Institute of Nuclear Agricultural Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China.
‡Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
J Agric Food Chem. 2015 Jul 15;63(27):6241-8. doi: 10.1021/acs.jafc.5b02143. Epub 2015 Jul 1.
We determined the relationships among the structural properties, in vitro digestibility, and genetic factors in starches of 14 rice cultivars. Weight-based chain-length distributions in amylopectin ranged from 18.07% to 24.71% (fa, DP 6-12), 45.01% to 55.67% (fb1, DP 13-24), 12.72% to 14.05% (fb2, DP 25-36), and 10.80 to 20.72% (fb3, DP > 36), respectively. The contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) ranged from 78.5% to 87.5%, 1.2% to 6.0%, and 10.1% to 18.0%, respectively. AAC was negatively correlated with RDS content but positively correlated with RS content in rice starch. The proportion of short chains in amylopectin, i.e. the amount of fraction IIa (FrIIa) fractionated by gel permeation chromatography (GPC), was positively correlated with RDS. Starch synthase IIa (SSIIa) gene controlled the degree of crystallinity, the amount of fa chains of amylopectin. SSIIIa gene controlled the amount of fb1 chains. Wx gene controlled the FrI, FrIIa, RDS, and RS. Starch debranching enzyme isoamylase II (ISA2) gene also controlled the RDS, which may suggest that RDS was also affected by amylopectin structure, although no correlation between them was found. This study indicated that genetics (i.e., starch biosynthesis related genes) controlled the structural properties of starch, and both amylose content and amylopectin fine structure determined functional properties of rice starch (i.e., the digestion), each in a different way. Understanding the "genetics-structure-function" relationships in rice starches will assist plant breeders and food processors in developing new rice varieties and functional foods.
我们确定了 14 种水稻品种淀粉的结构特性、体外消化率和遗传因素之间的关系。直链淀粉的重量链长分布范围为 18.07%至 24.71%（fa，DP 6-12）、45.01%至 55.67%（fb1，DP 13-24）、12.72%至 14.05%（fb2，DP 25-36）和 10.80 至 20.72%（fb3，DP>36）。快速消化淀粉（RDS）、缓慢消化淀粉（SDS）和抗性淀粉（RS）的含量范围分别为 78.5%至 87.5%、1.2%至 6.0%和 10.1%至 18.0%。AAC 与水稻淀粉中的 RDS 含量呈负相关，与 RS 含量呈正相关。直链淀粉中短链的比例，即凝胶渗透色谱（GPC）分离的 IIa 级分（FrIIa）的量，与 RDS 呈正相关。淀粉合成酶 IIa（SSIIa）基因控制结晶度和直链淀粉中 fa 链的量。SSIIIa 基因控制 fb1 链的量。Wx 基因控制 FrI、FrIIa、RDS 和 RS。淀粉分支酶异淀粉酶 II（ISA2）基因也控制 RDS，这表明 RDS 也受直链淀粉结构的影响，尽管它们之间没有相关性。本研究表明，遗传因素（即与淀粉生物合成相关的基因）控制淀粉的结构特性，直链淀粉含量和支链淀粉精细结构决定了水稻淀粉的功能特性（即消化），两者以不同的方式起作用。了解水稻淀粉的“遗传-结构-功能”关系将有助于植物育种家和食品加工者开发新的水稻品种和功能性食品。
