果蔬压差膨化干制品多孔结构的形成机理与调控

Explosion puffing is a technique used for controlling the texture and drying of fresh fruit and vegetables. During puffing, as the pressure drops abruptly, the superheated water inside fruit and vegetable gasifies and puffs the fruit and vegetables and form a kind of porous structure which is determining factor in the texture quality of food. A lot of factors are involved in the very short puffing process but little is known about intrinsic relationship between puffing parameter, puffing process and porous structure of the puffed products. We proposed to investigate to mechanism of bubble nucleation, the growth, shrinkage, and breakage of internal gas bubbles and set up a finite element analysis model to illuminate the dynamic fluid field, water concentration field, temperature field, force field based on the heat, mass, and momentum transfer and deformation of viscoelastic material. The mathematical models for the relationship between porous structure and textural properties will be set up, theoretical guidelines for control the texture and structure of puffed product will be put forward.

压差膨化是通过瞬间泄压使果蔬内部水分急剧相变，从而导致果蔬结构变化、体积膨胀、干燥的一种新型果蔬质构调控方法。果蔬压差膨化干制品的多孔结构是膨化过程中力、果蔬物性、热质传递等综合作用的结果，对产品质构具有决定性影响。但因膨化时间短，影响因素复杂，目前的研究主要集中在工艺与产品品质方面，对压差膨化过程、孔隙结构的形成机制尚缺乏本质上的认识。基于此，本项目提出果蔬内部气核形成基础理论，通过实验、理论分析、数值模拟相结合的方法，全面、系统地研究果蔬压差膨化过程涉及的力、果蔬物性以及热量、质量、动量传递等多物理过程机制，建立果蔬样品内部气泡生长、收缩变形、破裂和宏观样品膨化的数学控制模型，得出压差膨化过程中果蔬样品体系内的气泡尺寸、膨化率、水分分布、温度场、力场、密度、开孔、闭孔等的动态变化规律，建立多孔结构与质构力学性能间的数学关系模型，提出果蔬压差膨化干制品结构、质构调控的理论与方法。

压差膨化是通过瞬间泄压使果蔬内部水分急剧相变，从而导致果蔬结构变化、体积膨胀、干燥的一种新型果蔬质构调控方法。果蔬压差膨化干制品的多孔结构是膨化过程中力、果蔬物性、热质传递等综合作用的结果，对产品质构具有决定性影响。但因膨化时间短，影响因素复杂，目前的研究主要集中在工艺与产品品质方面，对压差膨化过程、孔隙结构的形成机制尚缺乏本质上的认识。基于此，本项目提出果蔬内部气核形成基础理论，通过实验、理论分析、数值模拟相结合的方法，全面、系统地研究了果蔬压差膨化过程涉及的力、果蔬物性以及热量、质量、动量传递等多物理过程机制，建立了果蔬样品内部气泡生长、破裂的数学控制模型，得出了压差膨化过程中果蔬样品体系内的气泡尺寸、水分分布、温度场、力、密度、开孔、闭孔等的动态变化规律及其影响因素。本项目从本质上系统、深入地研究果蔬压差膨化干制品多孔结构的形成机理，对全面揭示果蔬压差膨化干燥机理，过程规律，进一步推进其理论与技术革新，开展果蔬压差膨化干制品的质构调控，优化压差膨化设备设计等方面具有关键性的基础研究和指导意义。