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.

淀粉分子首先通过唾液和胰腺 α-淀粉酶降解为可缓慢消化的 α-极限糊精 (α-LDx) 和可快速水解的线性麦芽寡糖 (LMO)。在这项研究中，我们使用 4,6-α-葡聚糖转移酶 (4,6-αGT) 设计了一种可缓慢消化的高度支化的 α-LDx，具有最大化的 α-1,6 键，从而产生较短的 α-1,4 侧具有增加分支点的链。结果表明，在不同直链淀粉含量的玉米淀粉中，新合成了一条主要由1-8个葡萄糖基单元组成的短外链，色谱纯化后支链α-LDx的α-1,6键比明显增加。从 4.6% 到 22.1%。体外和体内_研究证实，酶促修饰的 α-LDx 改善了缓慢消化的特性并延长了血糖反应。因此，4,6-αGT 处理增强了高度支化的 α-LDx 的缓慢消化特性，并有望用作减弱餐后葡萄糖稳态的功能成分。