脉冲电场强化提取-膜分离耦合制备菊粉的规律及机理研究

Inulin is a nature fructan, which has attracted more and more interests for its applications in food and medicine field. However, current industrial production of inulin requires high extraction temperature (～80℃), long duration(1-2 hours) and complex purification process. The previous studies have confirmed that pulsed electric fields (PEF) technology facilitated reduction of extraction temperature and membrane technology simplified purification of inulin extract. However, the mechanism of inulin extraction intensification caused by PEF is not clear, the efficiency of membrane technology for purification of inulin with different molecular weight and the fouling mechanism during filtration also requires further study. Therefore, coupled process of PEF assisted extraction and membrane process will be used in this project, to realize cold extraction and fractional inulin production. The mechanism of inulin extraction intensification caused by PEF treatment will be studied, a mathematical model will be established, the effect of PEF treatment on molecular weight distribution of extracted inulin will be investigated and the strategies of the regulation to extract inulin with desired molecular weight will be established. Then, the purification efficiency of the membrane process to product inulin with desired molecular weight will be studied, also the model of membrane fouling will be proposed and effective membrane cleaning method will be developed. The process in this project will not only provide reliable theory and experimental evidences together with technical conditions for inulin cold extraction, cleaning production and fractional preparation, but also provide a platform for other nature extracts production.

菊粉是一种在食品和医药领域越来越受到关注的天然果聚糖，也是研究最广泛的益生元之一。针对目前传统工业菊粉生产温度高(～80℃)、时间长(1-2小时)、能耗大、级分多以及纯化工艺复杂的特点，本项目前期研究发现脉冲电场技术有利于菊粉提取温度的降低，而膜分离技术可简化菊粉纯化工艺。但是，脉冲电场强化菊粉提取传质机理模型尚待构建，膜分离技术分级纯化菊粉的效率以及菊粉提取液膜分离过程中的膜污染机理也尚待研究。因此，本项目拟采用脉冲电场强化提取与膜分离技术工艺相耦合，实现菊粉低温提取和分级制备。研究脉冲电场处理强化菊粉传质机理，建立适用于本体系的传质数学模型并建立调控菊粉分级提取的策略，研究膜耦合装置对不同分子量菊粉的分离效率并建立膜污染模型和开发有效地膜清洗方法，为菊粉的低温提取和清洁分级生产提供可靠的理论支撑、实验依据和技术条件，同时也可为相关天然提取物的生产提供良好的技术平台。

菊粉是一种天然碳水化合物和膳食纤维，也是一种具有多种功效的益生元，已被许多国家列为天然食品配料，我国已将菊粉列入新资源食品目录，具有极大的应用前景。本项目以我国大面积种植的菊芋为原料，围绕菊粉的提取传质强化、分离纯化、生理功能和应用开展了探索与研究。主要工作和成果如下： (1)建立基于酸水解的HPLC-ELSD菊粉测试方法，该方法回收率、精密度高，准确性、稳定性好;(2)研究了脉冲电场对菊芋材料结构和菊粉传质的影响，通过脉冲电场预处理可显著提高菊芋材料可压缩性和菊粉传质扩散速率。采用脉冲电场预处理可实现菊粉的中低温高效提取;(3) 超滤膜（截留分子量50kDa)过滤可有效去除提取液中的蛋白杂质，降低提取液浊度，提高菊粉纯度。膜过滤过程中的膜污染机制随膜孔径变化;(4) 不同干燥方式所得菊粉物理化学特性具有明显区别，喷雾干燥在产率、粒径分布、菊粉含量等方面指标优于冷冻干燥。菊粉添加可显著改善面团加工特性，并增加曲奇饼干的持水性和抗氧化性;(5) 菊粉可以促进高脂小鼠血液的抗氧化能力，降低血清总胆固醇，提高高密度脂蛋白/低密度脂蛋白比例，降低小鼠肝脏丙二醛和晚期糖基化终产物含量;(6) 发表SCI收录英文论文4篇，申报国家发明专利1项，培养硕士研究生2名。