纳滤法制备高纯度雪莲果低聚果糖及其结构表征

采用纳滤分离技术以雪莲果为原料纯化低聚果糖，通过Box-Behnken中心组合设计（CCD）及响应面分析（RSM）建立预测低聚果糖纯度的二次多项数学模型，优化分离纯化工艺。结果表明：操作压力0.15 MPa，循环流量5.3 mL/min，pH值2.7时，纯化倍数为5，实际低聚果糖纯度为95.1%，达到P级产品标准。通过应用HPLC-MS、IR、¹H NMR及¹³C NMR等对雪莲果低聚果糖组分的纯度、组成、结构进行表征，结果表明：分离纯化得到的雪莲果低聚果糖由蔗果三糖、蔗果四糖和蔗果五糖组成，纯度为95.1%，平均包含5个果糖单元，主要是由β-呋喃构型的果糖组成。

Preparation of High Purity Yacon Fructo-oligosaccharides by Nanofiltration and Its Characterization

The yacon fructo-oligosaccharides(FOS) was separated and purified by the nanometer membrane from yacon. A quadratic mathematical model for predioting the concentration of oligosaccharides was developed to optimize the purification process by Box-Behnken central composite design(CCD) and response surface methodology(RSM). Consequently, the optimized processing parameters were determined as operating pressure 0.15 MPa, circulation flow rate 5.3 mL/min, pH value 2.7, purification fold 5, the purity of the obtained FOS was 95.1%, which could reach P grade standard. HPLC-MS, IR, ¹H NMR and ¹³C NMR were used to characterize the purity, composition and structure of FOS. The results showed that the purified FOS was composed of kestose, nystose and bestonentaose. The purity was 95.1% and it contained on average of 5 fructose units. The yacon FOS was mainly composed of β-furan-fructose tested by IR.