QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
Carbohydr Polym. 2016 Sep 5;148:290-9. doi: 10.1016/j.carbpol.2016.03.034. Epub 2016 Mar 18.
The hydroxyl radicals (HO) are one of the most reactive oxygen species (ROS) involved in the oxidative damage of biological molecules, including carbohydrates. During the industrial processing of food, ROS can be formed. In order to identify the structural changes induced in starch by oxidation, amylose, amylopectin, and maltotriose, an oligosaccharide structurally related to these polysaccharides, were subjected to oxidation with HO generated under Fenton reaction conditions (Fe(2+)/H2O2). The oxidised polysaccharides were hydrolysed by α-amylase and the obtained oligosaccharides were fractionated by ligand-exchange/size-exclusion chromatography. Both acidic and neutral α-amylase resistant oligosaccharides were characterized by mass spectrometry. In oxidised neutral products, new keto, hydroxyl, and hydroperoxy moieties, and oxidative ring scission were observed at the reducing end of the oligosaccharides. The acid sugar residues occurred at the reducing end and included gluconic and glucuronic acid derivatives, and acids formed by oxidative ring scission, namely, arabinonic, erythronic, glyceric and glycolic acids.
羟基自由基（HO）是参与生物分子氧化损伤的最具反应性的氧自由基（ROS）之一，包括碳水化合物。在食品的工业加工过程中，可能会形成 ROS。为了鉴定氧化引起的淀粉结构变化，将直链淀粉、支链淀粉和麦芽三糖（与这些多糖结构相关的低聚糖）用芬顿反应条件（Fe（2+）/H2O2）产生的 HO 进行氧化。用α-淀粉酶水解氧化多糖，并通过配体交换/尺寸排阻色谱法对得到的低聚糖进行分级。通过质谱法对酸性和中性α-淀粉酶抗性低聚糖进行了表征。在氧化的中性产物中，在低聚糖的还原端观察到新的酮、羟基和过氧基团，以及氧化环的断裂。酸糖残基出现在还原端，包括葡萄糖酸和葡萄糖醛酸衍生物，以及由氧化环断裂形成的酸，即阿拉伯糖酸、赤藓糖酸、甘油酸和乙醇酸。
