菊粉羧甲基化修饰及其抗氧化活性研究

Antioxidant Activities of Inulin and Carboxymethyl Inulin

以菊粉为原料,采用溶媒法对菊粉进行羧甲基化修饰,研究了碱化时间、醚化时间、NaOH用量、溶剂体积分数四因素对羧甲基菊粉制备的影响,以取代度为指标,确定最佳修饰工艺条件。在该条件下,比较菊粉羧甲基修饰前后抗氧化活性的变化。结果表明,最佳工艺条件为碱化时间40 min、醚化时间70 min、m(菊粉)∶m(NaOH)∶m(氯乙酸)=27∶4∶13.8、异丙醇95%,取代度为0.682,当浓度为1mg/mL时,与修饰前菊粉相比,羧甲基菊粉清除羟自由基、DPPH、超氧阴离子自由基分别提高了12.6%、24.0%、13.9%。

In this study, the carboxymethylation of inulin was investigated. The modified parameters including alkalization time, etherification time, NaOH dosage and isopropyl alcohol volume fraction were studied using orthogonal test with sub- stitution degree as index. The optimized conditions were as follows ： alkalization time 40 rain, etherification time 70 min, m （Inulin） ： m （NaOH） ： m （ chloracetic acid） = 27： 4： 13.8, isopropyl alcohol volume fraction 95 %. Under these condi- tions, a maximum substitution degree of carboxymethyl inulin of 0.628 was obtained. Compared with unmodified inulin, the scavenging activities of carboxymethyl inulin at 1 mg/mL concentration level on DPPH free radicals, hydroxyl radi- cals and superoxide anion increased 12.6% ,24.0%, 13.9% respectively.