扫频超声的原位声谱监控及对黄秋葵冻干热质传递效率影响机理研究

The improvement of material heat and mass transfer efficiency is one of the core scientific problems in the development of freeze-drying with energy conservation and high efficiency. The ultrasound pretreatment of material is a new method to reduce production cost and improve freeze-drying efficiency. The okra has large volume and heterogeneous tissue with viscous gum polysaccharide. Thus, it is difficult to meet the improvement of heat and mass transfer efficiency of freeze-drying by fixed frequency ultrasound pretreatment. In this project, the pre-judgement and regulatory model “sweeping frequency ultrasound pretreatment → pulsation behavior of cavitation bubbles → heat and mass transfer efficiency” will be built according to black-box method in cybernetics. The sweeping frequency ultrasound equipment developed by our research group will be used to assist freeze-drying of okra, and the acoustic sensor monitoring system will be introduced to construct the mechanism of sweeping frequency ultrasound pretreatment based on in-situ monitoring of acoustic spectrum. On this basis, the various tissues of okra will be separated, and their thermodynamic/kinetic processes will be analyzed individually, and the theoretical system of heat and mass transfer will be perfected. For sensory and biochemical properties, the correlation between freeze-drying quality of okra and acoustic characteristic of sweeping frequency ultrasound field will be established, and the influencing effect of sweeping frequency ultrasound pretreatment on the freeze-drying efficiency will be revealed at the biological molecular level. Ultimately, the reference of research strategy will be provided for the green intelligent development of fruit and vegetable drying technology and mechanism reveal of ultrasonic application in other fields.

物料热质传递效率的提高，是冷冻干燥节能化、高效化发展面临的核心科学问题之一。对物料进行超声预处理，是降低生产成本、提高冻干效率的新方法。黄秋葵，体积较大且组织不均一、含有黏性胶质多糖，采用定频超声预处理难以满足冻干热质传递效率提高的需求。本项目根据控制论黑箱方法，建立“扫频超声预处理→空泡脉动行为→热质传递效率”预判与调控模型，利用课题组开发的扫频模式超声设备辅助黄秋葵冷冻干燥，引入声传感器监测系统，构建扫频超声预处理的原位声谱监控机理；在此基础上，对黄秋葵各组织结构进行分离制备，逐个分析黄秋葵及其不同组织结构的热/动力学过程，完善热质传递理论体系；在感官、生化属性方面，建立黄秋葵冻干品质与扫频超声场声特性之间的相关性，从生物分子水平进一步揭示扫频超声预处理对冻干效率影响机理。最终，为果蔬干燥技术绿色智能化发展，以及超声技术在其它领域应用机理揭示，提供研究策略参考。

为解决核心科学问题：提高物料热质传递效率，促进干燥节能化和高效化发展，对其进行超声预处理，降低生产成本并提高干燥效率，以“扫频超声预处理与黄秋葵干燥热质传递效率预判体系、扫频超声预处理与空泡脉动行为调控体系、扫频超声的原位声谱监控应用与验证”为主线，进行项目研究。开展了扫频超声预处理技术对黄秋葵真空脉动干燥特性及其品质的影响；融合其它预处理手段，进一步开发了扫频超声-冻融预处理技术对黄秋葵真空冷冻干燥特性及其品质的影响，为黄秋葵干燥技术的机械智能化发展提供理论基础。基于原位声谱监控技术，对黄秋葵扫频超声预处理过程进行原位声谱监控；在此基础上，构建扫频超声预处理对黄秋葵果胶的影响及其原位声谱监控的关联，为黄秋葵加工处理源头—扫频超声预处理效能的提升与调控提供机理借鉴。在本项目研究全部完成的前提下，将本项目中的亮点技术—扫频超声的原位声谱监控技术应用到对其它物料处理过程中，并研究超声场对这些物料传质效率的影响，验证本项目亮点技术的可及性与价值性。项目按照研究计划全部完成研究内容，同时还进行了系统性的完善、补充与应用。在国内外学术期刊发表论文9篇，其中，SCI论文8篇；申请发明专利6件；培养研究生4名；以本项目研究思想延续扩展，指导学生获得2021年江苏省研究生科研与实践创新计划1项，江苏大学校级大学生创新训练计划项目3项；参加会议4次；申请人当选为江苏省农业工程学会青年工作委员会常务委员；参与完成中国农学会的科学技术成果评价报告1份；获得技术开发（委托）横向项目1项，促进本项目研究成果转化。同时，基于本项目研究成果，还可应用于其它领域并进行探索研究。