Development of oxidized starch with functional properties by regioselective oxidation technology is of interest and provides a new research direction for starch science. In this work, the green-chemistry method of the laccase-TEMPO system was chosen to regioselectively oxidize the C6-OH groups of native maize starch (NMS), and the multi-scale structure evolution and water absorption properties of oxidized maize starch (OMS) were investigated. The results showed that regioselective oxidation slightly degraded the OMS chains and destroyed part of the short-range ordered structure, aggregate structure and crystalline structure, while the crystalline type, amorphous lamellae thickness and morphology of the starch granules were largely maintained. This implied that regioselective oxidation occurred not only in the amorphous lamellae (at low carboxyl content) but also in the crystalline lamellae (at high carboxyl content), leading to a shift from ordered to disordered structures and making the molecular chain arrangement less dense. Interestingly, the disordered transformation of the starch structure and the introduction of hydrophilic carboxyl groups enhanced the water absorption properties of OMS (increased 34.08–110.07% compared with NMS), and it increased with the increase of carboxyl content of OMS. Overall, this study could provide green processing methods and fundamental data for the development of oxidized starch with high water absorption.

利用区域选择性氧化技术开发具有功能特性的氧化淀粉具有重要意义，为淀粉科学提供了一个新的研究方向。在这项工作中，选择了漆酶-TEMPO 系统的绿色化学方法来区域选择性氧化天然玉米淀粉 (NMS) 的 C6-OH 基团，以及氧化玉米淀粉 (OMS) 的多尺度结构演变和吸水特性) 进行了调查。结果表明，区域选择性氧化轻微降解了OMS链并破坏了部分短程有序结构、聚集结构和晶体结构，而淀粉颗粒的结晶类型、无定形片层厚度和形态基本保持不变。这意味着区域选择性氧化不仅发生在无定形片层（低羧基含量）中，而且发生在结晶片层（高羧基含量）中，导致结构从有序向无序结构转变，并使分子链排列密度降低。有趣的是，淀粉结构的无序转变和亲水性羧基的引入增强了OMS的吸水性能（与NMS相比提高了34.08-110.07％），并且随着OMS羧基含量的增加而增加。总体而言，本研究可为高吸水性氧化淀粉的开发提供绿色加工方法和基础数据。导致从有序结构向无序结构转变，并使分子链排列密度降低。有趣的是，淀粉结构的无序转变和亲水性羧基的引入增强了OMS的吸水性能（与NMS相比提高了34.08-110.07％），并且随着OMS羧基含量的增加而增加。总体而言，本研究可为高吸水性氧化淀粉的开发提供绿色加工方法和基础数据。导致从有序结构向无序结构转变，并使分子链排列密度降低。有趣的是，淀粉结构的无序转变和亲水性羧基的引入增强了OMS的吸水性能（与NMS相比提高了34.08-110.07％），并且随着OMS羧基含量的增加而增加。总体而言，本研究可为高吸水性氧化淀粉的开发提供绿色加工方法和基础数据。