This study investigated the effect of ultrasound-assisted enzymatic extraction (UAEE) on the extraction efficiency, antioxidant activity, and structural properties of jujube polysaccharide (JPS), with hot water extraction (HWE), ultrasound-assisted extraction (UAE), and enzymatic-assisted extraction (EAE) serving as controls. Optimal extraction conditions were determined through a multi-index weighted scoring method that comprehensively accounted for yield, duration, and antioxidant activity. Results demonstrated that the JPS yield obtained by UAEE at 22/33 kHz was 10.5 % to 16.3 % higher than those achieved by the other methods, significantly enhancing antioxidant activity. Monosaccharide composition analysis revealed that UAEE increased the content of key mono-sugars in JPS. Additionally, assessments of molecular weight distribution, zeta potential, and rheological properties showed that UAEE reduced the molecular weight and apparent viscosity of JPS, resulting in a looser structural configuration. These structural modifications were observed in scanning electron microscope (SEM) images, which revealed a filamentous branched morphology in JPS obtained through UAEE. Further observations using the atomic force microscope (AFM) indicated that the polysaccharide chains extracted by UAEE were shorter in length, lower in height, and free from aggregation.

中文翻译：

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超声辅助酶法提取枣 （Ziziphus jujuba Mill.） 多糖：提取效率、抗氧化活性和结构特征


本研究以热水萃取 （HWE） 、超声辅助萃取 （UAE） 和酶辅助萃取 （EAE） 为对照，探讨了超声辅助酶萃取 （UAEE） 对红枣多糖 （JPS） 提取效率、抗氧化活性和结构特性的影响。通过综合考虑产量、持续时间和抗氧化活性的多指数加权评分方法确定最佳提取条件。结果表明，UAEE 在 22/33 kHz 下获得的 JPS 产量比其他方法高 10.5 % 至 16.3%，显着增强了抗氧化活性。单糖组成分析显示，UAEE 增加了 JPS 中关键单糖的含量。此外，对分子量分布、zeta 电位和流变特性的评估表明，UAEE 降低了 JPS 的分子量和表观粘度，导致结构构型更松散。在扫描电子显微镜 （SEM） 图像中观察到这些结构修饰，揭示了通过 UAEE 获得的 JPS 中的丝状分支形态。使用原子力显微镜 （AFM） 的进一步观察表明，UAEE 提取的多糖链长度较短，高度较低，且无聚集。