响应面试验优化海蓬子外种皮水溶性多糖提取工艺及其抗菌活性

Optimization of Extraction and Antimicrobial Activity of Water-Soluble Polysaccharides from Salicornia bigelovii Torr.Testa

对海蓬子外种皮多糖提取工艺进行研究,以干枯的海蓬子外种皮为原料,水提醇沉法获得多糖,考察提取时间、提取温度、料液比对多糖提取量的影响,通过单因素试验和响应面法对影响海蓬子外种皮多糖提取量的主要因素进行分析优化,微孔-平板法测定粗多糖对金黄色葡萄球菌、大肠杆菌的最小抑菌浓度(minimal inhibitory concentration,MIC)。结果表明:影响海蓬子外种皮多糖提取量工艺的因素按主次顺序排列为提取温度>料液比>提取时间;确定海蓬子外种皮多糖水提取的最佳工艺条件为提取温度87℃、提取时间5 h、料液比1∶57(g/m L),在该条件下,海蓬子外种皮多糖的提取量为(13.03±0.63)mg/g,与预测值12.42?mg/g接近,粗多糖对金黄色葡萄球菌、大肠杆菌的MIC值分别为50、100?mg/m L,由此表明,响应面模型与实际情况拟合良好,能较好地预测海蓬子外种皮多糖的提取量,海蓬子外种皮粗多糖对金黄色葡萄球菌、大肠杆菌抑制作用。

A water extraction-alcohol precipitation method to extract water-soluble polysaccharides from the dry testa of Salicornia bigelovii Torr. was developed in this study. The extraction process was optimized by investigating polysaccharide yield as a function of extraction time, extraction temperature and solid to solvent ratio using combination of one-factor-at- a-time experiments and response surface methodology. Minimal inhibitory concentrations （MICs） of crude polysaccharides from S. bigelovii Tort. testa against Staphylococcus aureus and Escherichia coli were detected by microweU plate method. The results showed that polysaccharide yield was affected in decreasing order by the three factors： extraction temperature, solid to liquid ratio and extraction time. An extraction temperature of 87℃, a solid to liquid ratio of 1：57 （g/mL） and 5 h extraction proved optimal. Expeximents carried out under the optimized conditions led to an extraction yield of （13.03 ± 0.63） mg/g, agreeing with the predicted value （12.42 mg/g）, indicating that the response surface model has good prediction ability for the extraction of polysaccharides from the testa of Salicornia bigelovii Torr.. Minimal inhibitory concentrations（MICs） of the crude polysaccharides against S. aureus and E. coli were 50 and 100 mg/mL, respectively, suggesting potent antibacterial activity.