Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215021, China.
Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th St., Troy, NY 12180, USA.
Carbohydr Polym. 2016 Aug 1;146:238-44. doi: 10.1016/j.carbpol.2016.03.040. Epub 2016 Mar 19.
Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions.
氧化淀粉是最重要的淀粉衍生物之一，具有许多不同的性质和应用。目前，有两种方法可以生产氧化淀粉，即通过特异性氧化和非特异性氧化。使用稳定的氮氧自由基 2,2,6,6-四甲基哌啶氧（TEMPO）与 NaBr 和 NaClO 进行特异性氧化，可以在良好的质量控制下生产出具有不同性质的氧化淀粉。在目前的研究中，我们研究了特异性氧化淀粉的产物。作为影响淀粉氧化的两个关键因素，氧化剂用量和温度得到了彻底的研究。使用凝胶渗透色谱法与多角度激光散射（GPC-MALLS）、红外（IR）光谱、核磁共振（NMR）光谱和四极杆飞行时间质谱（Q/TOF-MS）对分子量（MW）、氧化度（DO）和相应产物的详细结构进行了分析。根据分析结果，建立了用特异性氧化剂 TEMPO-NaBr-NaClO 处理淀粉的氧化模式。当使用大量氧化剂时，淀粉中的更多葡萄糖残基被氧化成葡萄糖醛酸（更高的 DO），并且观察到淀粉低聚糖的大量降解。通过选择 25°C 的反应温度，可以在给定量的氧化剂下获得高 DO。氧化淀粉中的还原端糖残基本身在所有 TEMPO-NaBr-NaClO 反应中被氧化并开环。此外，在一些产品的还原端残基中，额外的氧化剂产生了额外的新结构，特别是在低温反应中。
