超声波法辅助定向降解阿拉伯半乳聚糖的研究

Ultrasonic-assisted Radical Process for Directed Degradation of Arabinogalactan

以落叶松(Larix gmelinii(Rupr.)Kuzen)的木屑为原料提取阿拉伯半乳聚糖(AG),并利用超声波辅助AG定向降解,以降解后阿拉伯半乳低聚糖(AG-O)对自由基清除率为检测指标,在单因素试验的基础上,再利用响应面优化确定最佳降解条件。研究结果表明:最佳降解条件为多糖质量浓度10 g/L、反应温度60℃、H2O2体积分数6%、超声波作用时间60 min,在此条件下获得的阿拉伯半乳低聚糖对·OH清除率为89.6%,且可使原阿拉伯半乳聚糖的分子质量由52 ku定向降解到25 ku左右,且多糖累积质量分数达到60%;AG-O抗氧化活性较AG明显增强,其IC50值由2.058 g/L降低到0.497 g/L。

Arabinogalactan （AG） was extracted from the sawdust of larch （ Larix gmelinii （Rupr.） Kuzen）. The arabinogalactan obtained was physically degraded by ultrasound-assisted free radicals. The free radical scavenging ability of decomposed AG was selected as an indicator on the evaluation of the antioxidant activity. On the basis of single-factor test, response surface optimization was used to determine the optimal degradation conditions, and the optimum conditions are found as follows： the dpolysaccharide concentration was 10 g/L; ultrasonic temperature was 60℃; the H 2 O 2 volume fraction was 6%;and the ultrasonic time was 60 min . Under this optimum degradation condition, the ·OH scavenging rate of arabinogalactan was 89.6%, and M r of AG was degraded from 52 ku to around 25 ku, and the cumulative weight fraction of this molecular weight reached 60%.Compared with AG, the antioxidant activity of arabinogalactan oligosaccharide（AG-O） obtained in the anti-oxidative activity was significantly enhanced, and its IC 50 value decreased from 2.058 g/L to 0.497g/L.