甜菊糖苷样品分析纯化方法研究进展

Research progress in purification methods for steviol glycosides testing in stevia sample

甜菊糖苷是一种高甜度、低热量、安全的天然甜味剂,在食品加工中应用广泛。常见甜菊糖苷有9种成分,其纯化测定较为复杂。本文对目前甜菊糖苷常用的纯化方法进行了综述,比较了沉淀法、吸附法和膜分离技术的优缺点和差异性。在沉淀法中,醇沉法相对化学絮凝法损失率低,不会引入其他杂质和无机离子且过程简单。在吸附法中,大孔吸附树脂可多次重复利用,成本较低,适宜大量粗提液进行纯化过滤;固相萃取小柱一般为一次性使用,更适合少量的样品粗提液。膜分离技术主要用于大规模提取生产中,该技术小样化纯化分离技术则适用于甜菊糖苷的检测。在进行高效液相检测前,甜菊糖苷粗提液可以先用醇沉法进行初步纯化,再用大孔吸附树脂或者固相萃取柱进行进一步精提,以提高色谱柱分辨率和使用寿命以及分析结果准确性。

Steviol glycoside is a kind of natural sweetener with high sweetness,low calorie and safety,which is widely used in food processing.Nine components of steviol glycosides are commonly found,and the purification and determination of steviol glycoside is complicated.In this paper,the common purification methods of steviol glycosides were reviewed,and the advantages and disadvantages of precipitation method,adsorption method and membrane separation were compared.In the precipitation method,the ethanol subsiding has a lower loss rate compared with the chemical flocculation method,and it does not introduce other impurities and inorganic ions,and with a simple process.In the adsorption method,the macroporous adsorption resin can be reused for many times,and the cost is comparatively low,which is suitable for purification and filtration of a large number of crude extract.Solid phase extraction column is generally used for one-time,which is more suitable for a small amount of sample crude extract.Membrane separation technology is mainly used in large-scale extraction and production,while the sampling purification and separation technology is suitable for the detection of steviol glycosides.In order to improve the resolution and service life of the column and the accuracy of the analysis results,the crude extract of steviol glycosides can be purified by ethanol subsiding method,and then further refined by macroporous adsorption resin or solid phase extraction column before high performance liquid phase detection.