posted on 2023-01-09, 19:35authored byMin Xu, Lei Pan, Binbin Wang, Xuan Zou, Aihua Zhang, Zhijiang Zhou, Ye Han
Levan is a microbial fructan widely explored in various
fields
owing to its excellent physical and biochemical properties. However,
little is known about its digestion and fermentation characteristics
in vitro. This study evaluated the potential prebiotic properties
of levan obtained by enzymatic synthesis. Scanning electron microscopy,
Fourier transform infrared spectroscopy, and nuclear magnetic resonance
spectroscopy showed that the primary structures of levan remained
stable after saliva–gastrointestinal digestion. The microtopography,
molecular weight, and functional group of levan were seriously damaged
during fecal fermentation. Moreover, the total short-chain fatty acid
levels increased significantly, especially for propionic acid, butyric
acid, and valeric acid. The 16S rDNA sequencing showed that levan
mainly increased the abundance of Firmicutes; in genus levels, certain
beneficial bacteria such as Megasphaera and Megamonas genera were remarkably
promoted, and the proliferation of harmful genera was inhibited (such
as Cedecea and Klebsiella). Overall, this study provided new insights into the potential probiotic
mechanism of levan.