Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150500, PR China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, PR China.
Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Sciences, Heilongjiang University, Harbin 150080, PR China.
Int J Biol Macromol. 2022 Sep 30;217:303-311. doi: 10.1016/j.ijbiomac.2022.07.057. Epub 2022 Jul 12.
The bacterial strain HDE-9 was isolated from sauerkraut and identified as Levilactobacillus brevis. An exopolysaccharide (EPS) was isolated and purified from L. brevis HDE-9, and a preliminary investigation of its structural characteristics and biological activity was conducted. The molecular weight of the EPS was >1.0 × 10 Da. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy revealed that the EPS was composed of α-(1 → 6) linked d-glucopyranose units. X-ray diffraction (XRD) data on the EPS revealed its non-crystalline amorphous structure. Scanning electron microscopy (SEM) of the EPS revealed a smooth surface with sheet structures. The EPS exhibited the high value in thermal stability, water solubility, water holding capacity (WHC), and emulsification activity (EA). The water contact angle of the EPS revealed relatively high hydrophobicity in the presence of sucrose. The EPS also showed a strong milk solidification capacity in a dose-dependent manner. The EPS could significantly improve the texture of yoghurt, indicating its potential application as a functional starter in the production of fermented dairy products.
从酸菜中分离出一株细菌 HDE-9，并鉴定为短乳杆菌。从短乳杆菌 HDE-9 中分离和纯化出胞外多糖（EPS），并对其结构特征和生物活性进行了初步研究。EPS 的分子量>1.0×10 Da。傅里叶变换红外（FT-IR）光谱和核磁共振（NMR）光谱表明 EPS 由α-（1→6）连接的 d-葡萄糖吡喃糖单元组成。EPS 的 X 射线衍射（XRD）数据显示其为非晶态无定形结构。EPS 的扫描电子显微镜（SEM）显示出具有片状结构的光滑表面。EPS 表现出高热稳定性、高水溶性、高持水力（WHC）和高乳化活性（EA）。在存在蔗糖的情况下，EPS 的水接触角表现出相对较高的疏水性。EPS 还表现出剂量依赖性的强牛奶凝固能力。EPS 可以显著改善酸奶的质地，表明其作为功能性发酵剂在发酵乳制品生产中的潜在应用。
