Structural variation and rheological properties of water-extractable arabinoxylans from six Greek wheat cultivars
Structural variation and rheological properties of water-extractable arabinoxylans from six Greek wheat cultivars
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DOI：
10.1016/j.foodchem.2010.11.038
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发表时间：
2011-05-15
期刊：
影响因子：
8.8
通讯作者：
Zoumpoulakis, P.
中科院分区：
文献类型：
--
作者：
Skendi, A.;Biliaderis, C. G.;Zoumpoulakis, P.
对制作面包质量不同的 6 个希腊小麦品种的面粉进行水提取（在 25 摄氏度下），然后用猪胰腺 α-淀粉酶消化以去除淀粉污染物，并用硫酸铵沉淀（饱和度为 95%），得到分子量差异显着的阿拉伯木聚糖分离物，分子量范围为 146,500 至 397,000，并且阿拉伯糖与木糖的比率（Ara/Xyl，在 0.57 和 0.71 之间变化）。阿拉伯木聚糖分离物仅含有少量蛋白质并且相对不含其他多糖污染物。一般来说，所有样品中都检测到反式阿魏酸与顺式阿魏酸含量的比例非常高。基因型也对这些多糖的分子特征产生影响。 H-1 NMR光谱揭示了未取代的(61.1-67.9%)和二取代的(19.4-28.1%)和单取代的木糖残基(10.0-16.6%)的变化。尽管 H-1 和 C-13 共振存在广泛重叠，但使用 2D NMR 波谱可以识别单个单糖残基的自旋序列并阐明其结构。阿拉伯木聚糖的物理化学性质的差异，例如临界浓度值（c*和c**）、粘度、剪切稀化行为以及胶凝能力，不能完全用分离多糖的分子大小和结构的差异来解释。 (C) 2010 Elsevier Ltd. 保留所有权利。
Aqueous extractions (at 25 degrees C) of flours from six Greek wheat cultivars that differed in their bread-making quality, followed by porcine pancreas alpha-amylase digestion to remove starch contaminants and precipitation with ammonium sulphate (saturation at 95%), yielded arabinoxylan isolates with notable differences in molecular weight, ranging from 146,500 to 397,000, and in arabinose-to-xylose ratios (Ara/Xyl, varying between 0.57 and 0.71). The arabinoxylan isolates contained only small amounts of proteins and were relatively free of other polysaccharide contaminants. Generally a very high ratio of trans to cis-ferulic acid content was detected for all samples. The genotype also had an impact on the molecular characteristics of these polysaccharides. H-1 NMR spectroscopy revealed variations in the un-substituted (61.1-67.9%) and di- (19.4-28.1%) and mono-substituted xylose residues (10.0-16.6%). Using 2D NMR spectroscopy, it was feasible to identify the spin sequence of individual monosaccharide residues and elucidate their structure, despite the extensive Overlapping of H-1 and C-13 resonances. Differences in the physicochemical properties of the arabinoxylans, such as the critical concentration values (c* and c**), viscosity, shear-thinning behaviour, as well as the gelling ability, could not be fully explained by differences in molecular size and structure of the isolated polysaccharides. (C) 2010 Elsevier Ltd. All rights reserved.