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对黑小麦麦麸戊聚糖进行提取、纯化及组成分析。分别以H2O、Ba(OH)2和Na(OH)2为提取介质,提取水溶性和水不溶性戊聚糖;采用(NH4)2SO4分级沉淀、乙醇分级沉淀、凝胶过滤柱层析等方法纯化戊聚糖粗提物,分析其得率和组成。结果表明:水提组分(WEP)主要由葡萄糖(Glc)、阿拉伯糖(Ara)和木糖(Xyl)组成,是β-葡聚糖(79%)和戊聚糖(21%)的混合物。NaOH碱提组分(AEP-Na)中Ara和Xyl含量相对较高,以戊聚糖为主要组成(71%),还含有29%的β-葡聚糖。Ba(OH)2碱提组分(AEP-Ba)主要由阿拉伯糖(Ara)和木糖(Xyl)组成,含有较纯的戊聚糖(96%)。WEP经35%饱和(NH4)2SO4溶液沉淀后,戊聚糖含量由纯化前的21%提高到35%。AEP-Na经DEAE-Sepharose CL-6B柱层析,分级组分AEP-Na1的单糖组成的物质的量比,即n(Ara)∶n(Xyl)∶n(Glc)=0.7∶1∶1.2,其中戊聚糖的n(Ara)/n(Xyl)=0.7。AEP-Ba经不同浓度乙醇沉淀分级组分的戊聚糖主要由Ara和Xyl组成。其n(Ara)/n(Xyl)在0.38~1.02之间,且Ara的取代度随着乙醇浓度的增加而增大。
Extraction, purification and composition analysis of black wheat bran and pentosan. Water-soluble and water-insoluble pentosan were extracted with H2O, Ba (OH) 2 and Na (OH) 2 respectively, and purified by (NH4) 2SO4 fractionation, ethanol fractionation and gel filtration chromatography Pentosan crude extract, analysis of its yield and composition. The results showed that WEP mainly consisted of Glc, Ara and Xyl, which was a mixture of β-glucan (79%) and pentosan (21%) . The content of Ara and Xyl in NaOH alkaline extraction component (AEP-Na) is relatively high, with pentosan as main component (71%) and 29% beta-glucan. The Ba (OH) 2 Alkaline Extraction Component (AEP-Ba) consists mainly of Ara and Xyl and contains relatively pure pentosans (96%). After precipitation of WEP in 35% saturated (NH4) 2SO4 solution, pentosan content increased from 21% before purification to 35%. AEP-Na The quantitative ratio of the monosaccharides of fraction AEP-Na1, namely n (Ara): n (Xyl): n (Glc) = 0.7: 1 1.2, where pentosan has n (Ara) / n (Xyl) = 0.7. Pentosans of AEP-Ba fractionated by different concentrations of ethanol mainly consist of Ara and Xyl. The n (Ara) / n (Xyl) ranged from 0.38 to 1.02, and the degree of substitution of Ara increased with the increase of ethanol concentration.