高降糖活性柠檬皮多糖制备工艺优化及结构表征

目的：优化柠檬皮多糖制备的最佳工艺并筛选出柠檬皮多糖高降糖活性组分。方法：采用超声波辅助酶法提取柠檬皮多糖，结合响应面试验探究其最佳提取工艺，通过DEAE-52阴离子层析柱、Sephadex G-100凝胶柱层析分离纯化得到均一多糖组分（命名LPs-1a），以α-葡萄糖苷酶筛选柠檬皮多糖有效降糖组分并分析其相对分子质量、单糖组成和特征基团。结果：柠檬皮多糖的最佳提取工艺为超声时间44 min、超声温度55 ℃、料液比1∶20 （g/mL）、纤维素酶添加量1.1%，此时柠檬皮多糖得率为6.83%，与预测值接近；筛选出的LPs-1a组分能显著抑制α-葡萄糖苷酶活性（P＜0.05），其IC₅₀值为（1.22±0.04） mg/mL。该组分相对分子质量为195 260，α-糖苷键和β-糖苷键连接具有吡喃糖环，形貌为纤维状的酸性多糖，由甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖和阿拉伯糖组成。结论：超声波辅助酶法有助于柠檬皮多糖高降糖活性成分的筛选。

Optimization of preparation process and preliminary structure characterization of polysaccharides from lemon peel with high hypoglycemic activity

Objective: This study aimed to optimize the preparation process of polysaccharides from lemon peel and screen out the components with high hypoglycemic activity. Methods: Ultrasonic assisted enzymatic extraction of lemon peel polysaccharide, combined with response surface test to explore the best extraction process, through DEAE-52 anion chromatography and Sephadex G-100 gel column chromatography separation and purification to obtain a homogeneous polysaccharide fraction (named as LPs-1a). The effective hypoglycemic components of lemon peel polysaccharides were screened by α-glucosidase and their relative molecular weight, monosaccharide composition and characteristic groups were analyzed. Results: The optimal extraction process of lemon peel polysaccharide was ultrasonic treatment for at 55 ℃ for 44 min with solid-liquid ratio 1∶20 (g/mL) and cellulase addition rate 1.1%. Under the control of these conditions, the yield of lemon peel polysaccharide was 6.83%, which was close to the predicted value. The LPs-1a fraction significantly inhibited the activity of α-glucosidase with （1.22±0.04） mg/mL of IC₅₀(P＜0.05). The relative molecular weight of this component was 195 260, and it was connected by α-glycosidic bonds and β-glycosidic bonds with a pyranose ring. The morphology of the polysaccharide was fibrous, and it was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose Conclusion: Ultrasound-assisted enzymatic method is helpful in screening the highly hypoglycemic active components of lemon peel polysaccharides.