Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, United States of America.
Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Carbohydr Polym. 2025 Jan 15;348(Pt A):122810. doi: 10.1016/j.carbpol.2024.122810. Epub 2024 Sep 26.
Feruloylated side-chain oligosaccharide substituents are a distinctive feature of cereal grains' arabinoxylans (AX), but less is known about non-feruloylated oligosaccharide side-chain substituents. In this study we explored non-feruloylated disaccharide side-chains from corn (Zea mays L.) AX that had not been exposed to alkaline conditions and successfully isolated and unequivocally characterized the structure, α-d-xylopyranosyl-(1 → 3)-l-arabinose. This structure is uniquely different from the oligosaccharide portion of the comparable feruloylated disaccharide compound. Qualitative screening showed that this non-feruloylated disaccharide is also present in wheat (Triticum aestivum L.), oats (Avena sativa L.), and popcorn (Zea mays L. var. everta). β-d-Xylopyranosyl-(1 → 2)-l-arabinose, the carbohydrate motif from feruloylated oligosaccharide side-chain substituents, was not found in a non-feruloylated form. Our data imply that non-feruloylated β-d-xylopyranosyl-(1 → 2)-l-arabinose side-chains may not be an authentic component of cereal AX, and that structural models of AX should be revised accordingly. Non-feruloylated oligosaccharide side-chains are indeed an authentic substituent of cereal AX, but their carbohydrate structures sharply diverge from their feruloylated counterparts.
阿魏酰基化侧链低聚糖取代基是谷物阿拉伯木聚糖（AX）的一个显著特征，但对非阿魏酰化低聚糖侧链取代基的了解较少。在这项研究中，我们探索了玉米（Zea mays L.）AX 中未暴露于碱性条件下的非阿魏酰化二糖侧链，并成功分离和明确表征了结构，α-d-吡喃木糖基-（1→3）-l-阿拉伯糖。该结构与可比阿魏酰化二糖化合物的低聚糖部分完全不同。定性筛选表明，这种非阿魏酰化二糖也存在于小麦（Triticum aestivum L.）、燕麦（Avena sativa L.）和爆米花（Zea mays L. var. everta）中。β-d-吡喃木糖基-（1→2）-l-阿拉伯糖，即阿魏酰化低聚糖侧链取代基的碳水化合物基序，未以非阿魏酰化形式存在。我们的数据表明，非阿魏酰化的β-d-吡喃木糖基-（1→2）-l-阿拉伯糖侧链可能不是谷物 AX 的真实成分，并且 AX 的结构模型应相应进行修订。非阿魏酰化的低聚糖侧链确实是谷物 AX 的真实取代基，但它们的碳水化合物结构与阿魏酰化的同类物明显不同。
