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Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191

Hundschell, Christoph; Braun, Andre; Wefers, Daniel; Vogel, Rudi; Jakob, Frank

Abstract:
Levan is a fructan-type exopolysaccharide which is produced by many microbes from sucrose via extracellular levansucrases. The hydrocolloid properties of levan depend on its molecular weight, while it is unknown why and to what extent levan is functionally diverse depending on ist size. The aim of our study was to gain deeper insight into the size-dependent functional variability of levan. For this purpose, levans of different sizes were produced using the water kefir isolate Gluconobacter albidus TMW 2.1191 and subsequently rheologically characterized. Three levan types could be identified, which are similarly branched, but differ significantly in their molecular size and rheological properties. The smallest levan (<10$^{7}$ Da), produced without adjustment of the pH, exhibited Newton-like flow behavior up to a specific concentration of 25% (w/v). By contrast, larger levans (>10$^{8}$ Da) produced at pH ≥ 4.5 were shear-thinning, and the levan produced at pH 5.0 showed a gel-like behavior at 5% (w/v). A third (intermediate) levan variant was obtained through production in buffers at pH 4.0 and exhibited the properties of a viscoelastic fluid up to concentrations of 15% (w/v). ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000119285
Veröffentlicht am 12.05.2020
Originalveröffentlichung
DOI: 10.3390/foods9020192
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Biowissenschaften (IAB)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2304-8158
KITopen-ID: 1000119285
Erschienen in Foods
Band 9
Heft 2
Seiten Art. Nr.: 192
Vorab online veröffentlicht am 14.02.2020
Schlagwörter levan, Gluconobacter, exopolysaccharide, hydrocolloid, molecular weight, rheology
Nachgewiesen in Web of Science
Scopus
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