紫皮洋葱低聚糖的提取及分离研究

Extraction and Separation of Oligosaccharides from Purple Onion

以新鲜紫皮洋葱为原料,采用热水浸提法提取洋葱低聚糖并对提取物进行分离研究。通过单因素实验及正交试验确定洋葱低聚糖的最佳提取工艺,利用薄层层析法(TLC检测)和质谱(MS)分析检测提取物,Bio gel P-2生物胶层析对糖分进行分离。结果表明:紫皮洋葱低聚糖的最佳提取工艺为料液比1∶5(g/m L)、提取温度70℃、提取时间80 min,在此提取工艺下,所提取到的低聚糖含量为3.92 mg/g。TLC检测分析和MS检测表明,紫皮洋葱提取物中有多种聚合度的糖类物质存在,HPLC分析显示,紫皮洋葱低聚糖主要组成为蔗果低聚糖,β-呋喃果糖苷酶能较好的对其水解,且凝胶层析结果表明Bio gel P-2凝胶可以对紫皮洋葱低聚糖进行初步分离。

In this paper,the onion oligosaccharides were extracted from fresh purple onion by hot water extraction method and the extracts were isolated and investigated.The extraction process of carbohydrates in the purple onion was optimized by single factor test and orthogonal test.The thin-layer chromatography（ TLC） and MS were used to detect the extractive and Bio gel P-2 filtration chromatography was used to separate the carbohydrates. The results showed that the best extract conditions of oligosaccharides from the purple onion were liquid ratio 1∶ 5,extract temperature 70 ℃ and extracting time 80 min.Under these conditions,the total carbohydrates content was up to 3.92 mg/g. TLC analysis indicated that the extracts of purple onion contained six oligosaccharides with different polymerization degree. HPLC analysis showed that the purple skin onion oligosaccharides mainly consisted of fructo-oligosaccharide,and β-fructofuranosidase could better hydrolyze them. The results of gel chromatography showed that Bio gel P-2 gel could be used for the initial separation of onion oligosaccharides.