燕麦β-葡聚糖结构表征与溶液性质研究

Structural and Solution Property Characterization of Oat β-Glucans

摘要:

【目的】 对燕麦β-葡聚糖（OBG）进行结构表征和溶液性质研究。 【方法】 采用热水提取和乙醇分级的方法制备了2种不同重均分子量（M_w）、数均分子量（M_n）、峰值分子量（M_p）的可溶性OBG。通过傅里叶变换红外光谱（FT-IR）、核磁共振（NMR）、X-衍射（XRD）、扫描电镜（SEM）、高效尺寸排阻色谱串联多角度激光散射（HPSEC-MALLS）和流变仪等对其进行结构表征和溶液性质测定。 【结果】 OBG-1和OBG-2的M_w分别为80.73×10⁴、8.05×10⁴ g/mol，得率分别为（4.86±0.55）%、（3.32±0.31）%，纯度分别为（94.21±0.17）%、（90.43±0.34）%。2种OBG均是由β-D-吡喃葡萄糖通过β-（1，3）-糖苷键和β-（1，4）-糖苷键混合连接的纤维状葡聚糖。与OBG-2相比，OBG-1结构中含有更多的纤维三糖（DP3）和纤维四糖（DP4），且其表面较光滑；另外，OBG-1在水溶液中表现出高黏度和凝胶性能。 【结论】 与单一的检测方法相比，多种仪器联合使用验证OBG结构与溶液性质的方法更加可靠，为其活性研究和在生理功能方面的应用提供了参考。

Abstract:

[Objective] This study aims to characterize the structure and investigate the solution properties of oat β-glucan (OBG). [Method] Two soluble OBGs with different weigh-average molecular weights (M_w), number-average molar weights (M_n), and peak molecular weights (M_p) were prepared by hot water extraction and ethanol classification. The structures and solution properties were characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), high performance size exclusion chromatography coupled with multi-angle laser light scattering (HPSEC-MALLS), and rheology. [Result] OBG-1 and OBG-2 showed the M_w of 80.73×10⁴ g/mol and 8.05×10⁴ g/mol, the yields of (4.86±0.55)% and (3.32±0.31)%, and the purity of (94.21±0.17)% and (90.43±0.34)%, respectively. Both OBG-1 and OBG-2 were fibrous glucans composed of β-D-glucopyranose molecules linked by β-(1,3)-glycosidic and β-(1,4)-glycosidic bonds. OBG-1 contained more cellotriose and cellotetrose and had a smoother surface than OBG-2. In the aqueous solution, OBG-1 exhibited high viscosity and gel properties. [Conclusion] The method combining multiple instruments to characterize the structure and solution properties of OBG is more reliable than single characterization methods, providing a reference for the research on the activity and physiological functions of OBG.