黑小麦麦麸戊聚糖的部分酸水解特征与甲基化分析  

Partial Acid Hydrolytic Characteristics and Methylation Analysis of Pentosans from Black-grained Wheat Bran

作　　者：孙元琳[1] 顾小红[2] 陕方[3] 张俊明[1] 崔武卫 

机构地区：[1]运城学院生命科学系,运城044000 [2]江南大学食品科学与技术国家重点实验室,无锡214122 [3]山西省农业科学院农产品综合利用研究所,太原030031 [4]加拿大农业部食品研究所

出　　处：《高等学校化学学报》2012年第5期964-968,共5页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:31101244);山西省高等学校优秀青年学术带头人支持计划项目资助

摘　　要：研究了黑小麦麦麸戊聚糖(AEPH)的部分酸水解特征及其糖链的取代度和取代方式等结构信息.分别采用0.02,0.1和0.2 mol/L的三氟乙酸(Trifluoroacetic acid,TFA)对AEPH进行部分酸水解,结合甲基化分析、GC-MS和HPLC等方法对AEPH的糖链结构和相对分子质量分布进行了分析.结果表明,戊聚糖AEPH的糖残基主要由阿拉伯糖(Araf)和木糖(Xylp)组成.其取代度(A/X),即Araf与Xylp的比值为0.60,并具有较高的相对分子质量(Mw=3.81×105).AEPH的主链由Xylp残基通过1→4连接形成木聚糖.主链Xylp在O2,O3或O2/O3位被Araf单取代或双取代.非取代(u)、单取代(m)和双取代(d)Xylp残基的组成比例为57.7∶22.0∶6.2.非取代与取代Xylp的比值为2.1,双取代与单取代Xylp比值(d/m)为0.3.Araf主要以非还原性末端T-Araf以及通过1→2和1→5连接形成低聚阿拉伯糖的形式与主链Xylp相连,或与T-Xylp相连形成戊聚糖分子的支链.The hydrolytic characteristics and the structural features of substitute degree as well as substitute patterns of pentosans（AEPH） from black-grained wheat bran were analyzed.AEPH was hydrolyzed with 0.02,0.1,and 0.2 mol/L trifluoroacetic acid（TFA）,respectively.The structural features and M w of AEPH were studied with methylation methods,combined with GC-MS and HPLC instruments.The results indicated that the residues of sugar constituents were mainly Araf and Xylp,with an Ara/Xyl（A/X） ratio of 0.60 and a high average molecular weight（M w） of 3.81×105.AEPH contained a xylan backbone of 1→4 linked Xylp residues which was mono- or disubstituted with Araf groups at position O3,O2 or at both O2 and O3 positions.The relative composition ratio of un-,mono-,and di-substituted Xylp in the arabinoxylan fraction was 57.7∶22.0∶6.2,with a high proportion of unsubstituted to substituted Xylp（2.1）,and a very low proportion of di- to monosubstituted Xylp residues（d/m,0.3）.Araf side groups were linked to Xylp residues of the backbone as terminal Araf single units.Moreover,small quantities of 1→2,and 1→5 linked Araf indicated the presence of short arabinan side chains terminated with T-Xylp residues.

关 键 词：黑小麦 戊聚糖 部分酸水解 甲基化分析 

分 类 号：O629[理学—有机化学]