İspirli Hümeyra, Arslan Şeyma, Tuncer Fatma, Kasapoglu Muhammed Z, Ortakcı Fatih, Tuncil Yunus Emre, Dertli Enes
Bayburt University, Faculty of Engineering, Food Engineering Department, Bayburt, Türkiye.
Istanbul Technical University, Faculty of Chemical and Metallurgical Engineering, Food Engineering Department, Istanbul, Türkiye.
Int J Biol Macromol. 2025 Aug;319(Pt 2):145442. doi: 10.1016/j.ijbiomac.2025.145442. Epub 2025 Jun 21.
The production of exopolysaccharides (EPS) by Lactic Acid Bacteria (LAB) is technologically crucial because it has a wide range of applications in food technology, biotechnology, and health. In the present work, a new quinoa sourdough isolate of Leuconostoc mesenteroides strain AK7 was identified as a novel producer of a dextran-type EPS. The monomeric units of EPS AK7 were confirmed by HPLC analysis, while NMR spectroscopy and GC-MS linkage analysis further verified the EPS structure as a branched dextran containing mainly (1 → 6)-linked α- D -glucose units with (1 → 3,6)-linked α- D -glucose unit as branching points. An average molecular weight of 1.2 × 10 Da was detected for glucan AK7. FTIR analysis was applied to determine the functional units of dextran AK7. In terms of thermal features, TGA and DSC analysis were applied and a specific degradation temperature of 300 °C was found for dextran AK7. The morphology of the lyophilized EPS displayed a rough, dense, and porous structure, as observed through SEM analysis. Dextran AK7 revealed a semi-crystalline nature detected by XRD analysis. These structural and functional properties of dextran AK7 produced by Leuconostoc mesenteroides AK7 from quinoa sourdough suggest its potential usage for food industry applications.
乳酸菌（LAB）产生胞外多糖（EPS）在技术上至关重要，因为它在食品技术、生物技术和健康领域有广泛应用。在本研究中，从藜麦酸面团中分离出的一种新的肠膜明串珠菌菌株AK7被鉴定为一种新型葡聚糖型EPS的生产者。通过HPLC分析确定了EPS AK7的单体单元，而核磁共振光谱和气相色谱 - 质谱联用分析进一步证实了EPS的结构为一种支链葡聚糖，主要含有（1→6）连接的α - D - 葡萄糖单元，以（1→3,6）连接的α - D - 葡萄糖单元作为分支点。检测到葡聚糖AK7的平均分子量为1.2×10 Da。应用傅里叶变换红外光谱（FTIR）分析来确定葡聚糖AK7的功能单元。在热特性方面，应用热重分析（TGA）和差示扫描量热法（DSC）分析，发现葡聚糖AK7的特定降解温度为300℃。通过扫描电子显微镜（SEM）分析观察到，冻干EPS的形态呈现出粗糙、致密和多孔的结构。通过X射线衍射（XRD）分析检测到葡聚糖AK7具有半结晶性质。藜麦酸面团中的肠膜明串珠菌AK7产生的葡聚糖AK7的这些结构和功能特性表明其在食品工业应用中的潜在用途。
