Structural Characterization of Glucan Produced by Lactobacillus sake L-7 from Sausage

摘要

A linear glucan was produced by Lactobacillus sake L-7 isolated from homemade sausage.Cultivation of the strain in ManRogosa-Sharpe (MRS) medium containing 50 g/L sucrose yielded 5.3 g/L of purified exopolysaccharide (EPS).The EPS was characterized by gas chromatography (GC),Fourier-transform infrared (FT-IR) spectroscopy,high-performance sizeexclusion chromatography (HPSEC),nuclear magnetic resonance (NMR) spectroscopy,and scanning electron microscopy (SEM).The monosaccharide composition of the EPS was glucose,and its molecular weight was 1 × 107 Da.The FT-IR and NMR spectra revealed that the L-7 EPS was a linear glucan with α-(1 → 6) glucosidic bonds.SEM images of the dried EPS revealed a hollow tubular structure.The water solubility index and water holding capacity of L-7 EPS were 96 and 272％,respectively.The results of hydrolysis indicated that L-7 EPS was not susceptible to hydrolysis by physiological barriers and can be used as a soluble dietary fiber with health benefits.All these characteristics suggest that L-7 EPS might have potential applications in the food,cosmetic,and pharmaceutical industries.