Chem. J. Chinese Universities ›› 2012, Vol. 33 ›› Issue (05): 964.doi: 10.3969/j.issn.0251-0790.2012.05.018

• Organic Chemistry • Previous Articles     Next Articles

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

SUN Yuan-Lin1, GU Xiao-Hong2, SHAN Fang3, ZHANG Jun-Ming1, CUI Wu-Wei4   

  1. 1. Department of Life Science, Yuncheng University, Yuncheng 044000, China;
    2. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China;
    3. Institute of Farm Products Comprehensive Utilization, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China;
    4. Food Research Program, Agriculture and Agri-Food, Ontario N1G5C9, Canada
  • Received:2011-07-12 Online:2012-05-10 Published:2012-05-10

Abstract: 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 Mw 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(Mw) 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.

Key words: Black-grained wheat, Pentosan, Partial acid hydrolysis, Methylation analysis

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