基于超声驱动磁性微纳米马达的苹果汁中有害微生物高效捕获-分离技术研究

Microbiological contamination is a very severe problem for apple juice products in China. The existing sterilization technologies could affect the quality of juice products and induce the release of endotoxin from microorganism, and even are often high cost. Therefore, developing green and efficient separation technologies towards whole harmful microorganisms can not only eliminate microbiological contamination, but also guarantee the quality and safety of the processed apple juice. In this project, by applying green and efficient ultrasound-propelled magnetic micro/nanomotor, the restricted Brownian motion of normal functional materials in apple juice with high viscosity and high ion concentration is reversed. Combined with the broad-spectrum recognition of lectin towards microorganisms and the convenient magnetic separation, an ultrasound-propelled magnetic micro/nanomotor which can move efficiently in juice and capture and separate a variety of microorganisms is designed. By studying the ultrasonic response of the micro/nanomotor in juice, the mechanism of its motion enhancement in juice is analyzed. Then the parameters of capture-separation, the corrosion resistance of micro/nanomotor in fruit juice and the impacts on the quality of the apple juice are explored. As such, based on ultrasound-propelled magnetic micro/nanomotor, an efficient capture-separation method towards harmful microorganisms in apple juice is established, providing an essential technological support to ensure the quality and safety of apple juice and also affording a new way for microorganism separation in other liquid foods.

有害微生物造成的我国苹果浓缩汁质量安全问题日益突显。现有灭菌技术存在造价高、易造成菌内毒素释放、影响果汁品质等不足，发展绿色、高效的有害微生物全菌分离技术，不仅可以消除微生物污染，更可以保障苹果汁加工后的品质和安全性。本项目拟以超声波对磁性微纳米马达的绿色高效驱动为核心技术，扭转功能材料在高粘度、高离子强度果汁中受限的布朗运动，并结合凝集素对微生物的广谱识别机制和磁性材料便捷分离的特性，设计并制备一种在果汁中可高效运动且能捕获-分离多种微生物的超声波驱动磁性微纳米马达。通过研究该马达在果汁中的超声波响应行为，解析其在果汁中运动加强的机制；优化马达捕获-分离果汁中有害微生物的参数，并考察其在果汁中的耐腐蚀性及对果汁品质的影响，最终构建基于超声波驱动磁性微纳米马达的苹果汁中有害微生物捕获-分离技术，为保障苹果汁质量安全提供必要的技术支撑，也为其它液态食品中微生物的分离提供新的思路和理论指导。

有害微生物造成的我国苹果浓缩汁质量安全问题日益突显。现有灭菌技术存在造价高、易造成菌内毒素释放、影响果汁品质等不足，发展绿色、高效的有害微生物全菌分离技术，不仅可以消除微生物污染，更可以保障苹果汁加工后的品质和安全性。本项目筛选出了可以在苹果汁中对有害微生物进行识别-捕获的两种天然物质（单宁酸、植酸），并通过理论计算证实了单宁酸对细菌的捕获机制主要是通过单宁酸与细菌表面肽聚糖的结合。进一步通过原位合成及金属离子对单宁酸的螯合作用，构建出单宁酸功能化的磁性微纳米马达，并明确该微纳米马达对超声波响应的机制。最后利用单宁酸对微生物的广谱识别机制、超声对微纳米马达的高效驱动作用以及磁性便捷分离的优势，采用所构建的基于超声驱动磁性微纳米马达的有害微生物高效捕获-分离技术，实现了对苹果汁中有害微生物的全菌高效捕获-分离。