Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Weihenstephaner Steig 16, D-85350 Freising, Germany.
Carbohydr Polym. 2013 Feb 15;92(2):1234-42. doi: 10.1016/j.carbpol.2012.10.054. Epub 2012 Oct 29.
Some strains of acetic acid bacteria (Gluconobacter frateurii TMW 2.767, Gluconobacter cerinus DSM 9533T, Neoasaia chiangmaiensis NBRC 101099, Kozakia baliensis DSM 14400) produce high amounts of fructans, which can be exploited in food applications as previously demonstrated empirically for dough systems. In order to get insight into the structure and functionality of these polymers, we investigated the fructans isolated from these strains with respect to their linkage types and molecular weights/shapes using NMR spectroscopy and AF4-MALS-RI. Each fructan was identified as levan. The isolated levan fractions were highly similar according to their basic linearity and linkage types, but differed significantly in terms of their individual molecular weight distributions. In aqueous solutions the size of levan molecules present in all isolated levans continuously increased with their molecular weight and they tended to adopt a more compact molecular shape. Our data suggest that the increasing molecular weight of a levan particle enforces intramolecular interactions to reach the structural compactness of a microgel with hydrocolloid properties.
一些醋酸菌菌株（Gluconobacter frateurii TMW 2.767、Gluconobacter cerinus DSM 9533T、Neoasaia chiangmaiensis NBRC 101099、Kozakia baliensis DSM 14400）产生大量的果聚糖，这些果聚糖可在食品应用中得到利用，这一点已被先前的面团系统经验证。为了深入了解这些聚合物的结构和功能，我们使用 NMR 光谱法和 AF4-MALS-RI 研究了从这些菌株中分离出的果聚糖的键合类型和分子量/形状。每种果聚糖都被鉴定为蔗果聚糖。根据其基本线性和键合类型，分离出的蔗果聚糖分数非常相似，但在各自的分子量分布方面存在显著差异。在水溶液中，所有分离出的蔗果聚糖中存在的蔗果聚糖分子的大小随着分子量的增加而连续增加，并且它们倾向于采用更紧凑的分子形状。我们的数据表明，蔗果聚糖颗粒的分子量增加会强制分子内相互作用，以达到具有水胶体性质的微凝胶的结构紧凑性。
