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>Optimized microwave extraction characterization and antioxidant capacity of biological polysaccharides from Eucommia ulmoides Oliver leaf
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Optimized microwave extraction characterization and antioxidant capacity of biological polysaccharides from Eucommia ulmoides Oliver leaf
Microwave-induced technique was combined with response surface methodology for optimizing the isolation of polysaccharides from Eucommia ulmoides Oliver leaf. The maximum polysaccharides yield of 12.31% was achieved by microwave extraction at 74 °C for 15 min with a solid to liquid ratio of 1:29 g/mL, which agreed with the predicted value and was 2.9-fold higher than that of the conventional heat-reflux extraction method. The dominant bioactive constituent in extracts was chlorogenic acid (1.3–1.9%), followed by geniposidic acid (1.0–1.7%). The polysaccharides from the optimized extraction had a high molecular weight and polydispersity (Mw 38,830 g/mol, Mw/Mn 2.19), as compared to the fraction prepared in the absence of microwave (Mw 12,055 g/mol, Mw/Mn 1.26). Glucose was the dominant sugar component (38.2–39.1%) of heterogeneous polysaccharides which belonged to a structure of β-type acidic heteropolysaccharides with a glucan group and highly branched degree. The polysaccharides showed a higher DPPH radical scavenging index (0.87–1.22) than BHT (0.41) but lower than BHA (3.56), which can act as a favorable antioxidant in functional food.
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机译:微波诱导技术与响应面法相结合,优化了杜仲叶多糖的分离工艺。在74 C微波萃取15 min固液比为1:29 g / mL时,多糖的最大产率为12.31%,与预期值相符,比常规值高2.9倍热回流提取法。提取物中的主要生物活性成分是绿原酸(1.3–1.9%),其次是异己二酸(1.0–1.7%)。与在无微波条件下制备的馏分(Mw 12,055 g / mol,Mw / Mn 1.26)相比,优化提取的多糖具有较高的分子量和多分散性(Mw 38,830,g / mol,Mw / Mn 2.19)。葡萄糖是异质多糖的主要糖成分(38.2–39.1%),属于具有葡聚糖基团和高度分支度的β型酸性杂多糖的结构。多糖显示出比BHT(0.41)高的DPPH自由基清除指数(0.87–1.22),但比BHA(3.56)低,可以作为功能食品中的良好抗氧化剂。
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