Towards a better understanding of bio-processing: drying/extraction and state/phase transitions

食品工程研究依赖于研究已知的过程和食品生物材料如何相互作用，赋予该领域新的特殊性。在这项提案中，与干燥和提取有关的现象将在微观水平上发生的相/状态转变研究的基础上被彻底应用于工业中的食品转化的两个大尺度过程。本计划将制定的具体研究目标，以及从研究结果中得出的独特的科学和工业意义如下： 1)收缩和淀粉转变：加深对空气干燥过程中淀粉和淀粉-水相互作用在食品收缩中作用的理解。 了解淀粉类食品干燥过程中的收缩与状态/相变之间的关系，将有助于制定最佳的干燥策略，以提高干燥食品的最终质量。 2)空气干燥与玻璃化转变的数学建模：建立了描述高水分食品中玻璃化转变时干燥过程中传质行为的非Fickian本构模型方程。 通过建立一个准确而简单的本构方程，包括玻璃化在干燥过程中水分传递的作用，我们将朝着高水分食品(或其他领域)应用的干燥过程的更精确的工业设计迈进。 3)低温萃取与结晶：分析了液氮浸渍提蜡过程中结晶和晶体生长对提高产率和萃取选择性的影响。 通过将组成和晶体结构与晶体生长动力学联系起来，将阐明液氮浸泡从植物表面分离蜡质的可能机理，从而提高蜡产率和提取物的量身定制的选择性，这可能为这种新的提取方法的具体应用提供启发。 上述目标通过过程工程、食品化学、植物学和材料科学研究领域的十字路口网络联系在一起。通过招聘和培养多学科领域的高素质人才来培养研究人才，将使这一科学计划的目标更加完善。

Food engineering research relays on the study of how already known processes and food biomaterials interact with each other, giving novel specificity to the field. In this proposal, phenomena related to drying and extraction, two macroscale processes thoroughly applied to transform foods in industry, will be investigated on the basis of the study of phase/state transitions occurring at the microscale level. Specific research objectives to be developed in this program, together with distinctive scientific and industrial implication from the research outcome, follow: 1) Shrinkage and starch transitions: to deepen the understanding of the role of starch and starch-water interactions in food shrinkage during air-drying. Understanding the relationship between shrinkage during drying of starchy foods and state/phase transitions will lead to optimal drying strategies for improvement of the final quality of dried foodstuffs. 2) Air-drying and glass transition through mathematical modelling: to develop a non-Fickian constitutive model equation for representing the mass transfer behavior during drying while glass transition occurs in high moisture food products. By developing an accurate yet simple constitutive equation including the role of vitrification in moisture transfer during drying, we will move towards a more precise industrial design of the drying process for high moisture foods (or other field) applications. 3) Cryogenic extraction and crystallization: to analyze the impact of crystallization and crystal growth in yield enhancement and extract selectivity during wax extraction using liquid nitrogen immersion. By relating composition and crystalline structure to crystal growth kinetics, possible mechanisms underlying the separation of waxes from plant surfaces by liquid nitrogen immersion will be elucidated, allowing increase in wax yield and tailor-made selectivity of extracts, which could enlight possible specific applications of this novel extraction method. The above-mentioned objectives are connected by a network of crossroads between process engineering, food chemistry, botany and material sciences research fields. Training of research talents by recruitment and preparation of high-qualified personnel in multidisciplinary areas will round up the objectives of this scientific program.