Shi Qiao, Hou Yaxi, Juvonen Minna, Tuomainen Päivi, Kajala Ilkka, Shukla Shraddha, Goyal Arun, Maaheimo Hannu, Katina Kati, Tenkanen Maija
Department of Food and Environmental Sciences, University of Helsinki , P.O. Box 27, FI-00014 University of Helsinki, Finland.
VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Finland.
J Agric Food Chem. 2016 Apr 27;64(16):3276-86. doi: 10.1021/acs.jafc.6b01356. Epub 2016 Apr 12.
Long-chain isomaltooligosaccharides (IMOs) are promising prebiotics. IMOs were produced by a Weissella confusa dextransucrase via maltose acceptor reaction. The inputs of substrates (i.e., sucrose and maltose, 0.15-1 M) and dextransucrase (1-10 U/g sucrose) were used to control IMO yield and profile. According to response surface modeling, 1 M sucrose and 0.5 M maltose were optimal for the synthesis of longer IMOs, whereas the dextransucrase dosage showed no significant effect. In addition to the principal linear IMOs, a homologous series of minor IMOs were also produced from maltose. As identified by MS(n) and NMR spectroscopy, the minor trisaccharide contained an α-(1→2)-linked glucosyl residue on the reducing residue of maltose and thus was α-d-glucopyranosyl-(1→2)-[α-d-glucopyranosyl-(1→4)]-d-glucopyranose (centose). The higher members of the series were probably formed by the attachment of a single unit branch to linear IMOs. This is the first report of such α-(1→2)-branched IMOs produced from maltose by a dextransucrase.
长链异麦芽低聚糖（IMOs）是很有前景的益生元。IMOs由嗜糖魏斯氏菌葡聚糖蔗糖酶通过麦芽糖受体反应产生。利用底物（即蔗糖和麦芽糖，0.15 - 1 M）和葡聚糖蔗糖酶（1 - 10 U/g蔗糖）的投入量来控制IMOs的产量和分布。根据响应面模型，1 M蔗糖和0.5 M麦芽糖对合成更长链的IMOs最为适宜，而葡聚糖蔗糖酶用量没有显著影响。除了主要的线性IMOs外，还从麦芽糖产生了一系列同源的次要IMOs。通过MS(n)和核磁共振光谱鉴定，次要的三糖在麦芽糖的还原端含有一个α-(1→2)连接的葡萄糖基残基，因此是α-d-吡喃葡萄糖基-(1→2)-[α-d-吡喃葡萄糖基-(1→4)]-d-吡喃葡萄糖（中间糖）。该系列的更高成员可能是通过在直链IMOs上连接单个单元分支形成的。这是关于由葡聚糖蔗糖酶从麦芽糖产生此类α-(1→2)分支IMOs的首次报道。
