Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, SE-750 07, Uppsala, Sweden.
Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 101, SE-230 53, Alnarp, Sweden.
Carbohydr Polym. 2021 Mar 1;255:117503. doi: 10.1016/j.carbpol.2020.117503. Epub 2020 Dec 13.
To determine the internal structure of barley starch without amylopectin isolation, whole starch was hydrolyzed using β-amylase to remove the linear amylose and obtain β-limit dextrins (β-LDs). The β-LDs were treated with extensive α-amylase to prepare α-limit dextrins (α-LDs), and the α-LDs were further hydrolyzed with β-amylase into building blocks. The chain-length distribution of β-LD and building block composition were analyzed by size-exclusion chromatography and anion-exchange chromatography. The internal structure of the barley whole starches had similar pattern to barley amylopectins analyzed by conventional methods. The starch of barley amo1-mutated varieties contained more short internal B-chains and less long internal B-chains than that of other varieties. The starch from amo1-mutated varieties had more large building blocks than that from waxy varieties. The simplified method presented in this study can effectively characterize starch internal structure that relates to physicochemical properties of starch, although some details of amylopectin structure are not assessable.
为了在不分离支链淀粉的情况下确定大麦淀粉的内部结构，使用β-淀粉酶将整个淀粉水解，以去除线性直链淀粉并获得β-极限糊精（β-LD）。将β-LD 用广泛的α-淀粉酶处理以制备α-极限糊精（α-LD），然后将α-LD 进一步用β-淀粉酶水解成构建块。通过尺寸排阻色谱法和阴离子交换色谱法分析β-LD 和构建块组成的链长分布。用常规方法分析的大麦支链淀粉的内部结构与大麦直链淀粉具有相似的模式。amo1 突变品种的淀粉比其他品种含有更多的短内部 B 链和更少的长内部 B 链。amo1 突变品种的淀粉比蜡质品种具有更多的大构建块。尽管不能评估支链淀粉结构的某些细节，但本研究中提出的简化方法可以有效地表征与淀粉理化性质相关的淀粉内部结构。
