Department of Food Science and Biotechnology, Gachon University, Seongnam 13120, Republic of Korea.
Key Laboratory of Agro-products Processing Technology at Jilin Provincial Universities, Education Department of Jilin Provincial Government, Changchun University, Changchun 130022, People's Republic of China.
Carbohydr Polym. 2022 Jan 1;275:118685. doi: 10.1016/j.carbpol.2021.118685. Epub 2021 Sep 21.
Starch molecules are first degraded to slowly digestible α-limit dextrins (α-LDx) and rapidly hydrolyzable linear malto-oligosaccharides (LMOs) by salivary and pancreatic α-amylases. In this study, we designed a slowly digestible highly branched α-LDx with maximized α-1,6 linkages using 4,6-α-glucanotransferase (4,6-αGT), which creates a short length of α-1,4 side chains with increasing branching points. The results showed that a short length of external chains mainly composed of 1-8 glucosyl units was newly synthesized in different amylose contents of corn starches, and the α-1,6 linkage ratio of branched α-LDx after the chromatographical purification was significantly increased from 4.6% to 22.1%. Both in vitro and in vivo studies confirmed that enzymatically modified α-LDx had improved slowly digestible properties and extended glycemic responses. Therefore, 4,6-αGT treatment enhanced the slowly digestible properties of highly branched α-LDx and promises usefulness as a functional ingredient to attenuate postprandial glucose homeostasis.
淀粉分子首先被唾液和胰腺α-淀粉酶降解为缓慢消化的α-极限糊精（α-LDx）和快速水解的线性麦芽低聚糖（LMOs）。在这项研究中，我们使用 4,6-α-葡聚糖转移酶（4,6-αGT）设计了一种具有最大化α-1,6 键的缓慢消化的高度支化的α-LDx，该酶可在不断增加分支点的情况下生成较短的α-1,4 侧链。结果表明，在不同玉米淀粉直链淀粉含量的情况下，新合成了一种主要由 1-8 个葡萄糖基单元组成的短外部链，并且经色谱纯化后支化α-LDx 的α-1,6 键比例从 4.6%显著增加到 22.1%。体外和体内研究均证实，经酶修饰的α-LDx 具有改善的缓慢消化特性和延长的血糖反应。因此，4,6-αGT 处理增强了高度支化的α-LDx 的缓慢消化特性，并有望作为一种功能性成分用于减轻餐后血糖稳态。
