高压静电场下肉类冻结-解冻特性变化规律与机理研究

High voltage electrostatic field (HVEF) is attracting more and more attention for its special properties during the meat freezing and thawing process. Previous study has shown that the pork tenderloin meat can keep unfrozen state stored at the temperature below freezing point. At the same time, through HVEF thawing, energy consumption can be saved by 1/2~1/3, and meat storage quality was improved. This study is to explore the influence law about electromagnetism characteristics of HVEF on water molecules state in meat, and the dependence between characteristic parameters of the electric field and mutual transformation about water dissolving and crystalline state. It is from cellular level to explore the reasons that HVEF inhibits the ice crystal formation thus reducing the muscle cells damage and the material loss such as amino acids. At the same time, in view of the impact of ozone and charged ions produced by HVEF on the meat surface microorganisms, as well as to the fat oxidation and protein denaturation, it reveals the mechanism of HVEF killing bacteria and improving meat product. It will construct mathematical models among HVEF parameters, meat characteristics and the defrosting efficiency. This study is from two general directions in fresh keeping and frozen thawing to preliminarily build HVEF platform and the basic parameters used for meat storage, and lay a solid theoretical basis for high efficiency and energy saving HVEF technology industrialization development.

高压静电场下（HVEF）肉类冻结和解冻过程表现出的特殊性质日益受到关注。前期研究表明，HVEF下猪里脊肉在低于冰点温度下贮藏，可保持不冻状态；通过HVEF解冻，可以缩短解冻时间，节约能耗1/2~1/3，肉类贮藏品质得到提高。本研究旨在探索HVEF的电磁学特性对肉类中水分子状态的影响规律，以及水的溶解-结晶态相互转化与电场特性参数的依存性。从细胞水平探索HVEF抑制冰晶形成进而减轻对肌细胞产生破损，降低氨基酸等物质流出的原因。同时，针对HVEF产生的臭氧和荷电离子对肉类表面微生物的作用，以及对脂肪氧化和蛋白质变性产生的影响，揭示HVEF致死微生物及提高肉类品质的机理。构建HVEF参数与肉类特性及解冻效率的数学模型。本研究从贮藏保鲜和冻藏解冻两大方向出发，初步建立HVEF用于肉品贮藏的基本参数和平台，为高效节能的高压静电场技术工业化发展奠定扎实的理论基础。

本项目设计了高压静电场（HVEF）冷冻与解冻平台，研究了HVEF作用下去离子水、明胶及猪里脊肉的冷冻历程。率先构建了解冻时间、能耗和电场强度的关系模型，比较了多种解冻技术的能量损耗，确立了HVEF解冻速率是自然解冻的2.29倍，解冻能耗小于190 kJ/kg，为常见解冻方法中的最低值。研究了HVEF对去离子水和猪里脊肉冷冻-解冻特性及对品质的影响，发现HVEF下去离子水的成核温度提高3.5°C，猪里脊肉没有体现出明显的成核温度。HVEF解冻后肉品冷藏期间微生物数量比对照低0.5-1 log CFU/g，挥发性盐基氮的含量也较低，解冻质量较优。开展了HVEF解冻对猪肉肌原纤维蛋白的影响，通过理化性质及蛋白质高级结构分析，发现该解冻方法未加剧蛋白质的氧化及变性，部分代谢物及挥发性风味物质含量存在差异。该成果明晰了HVEF处理后猪肉蛋白质的理化特性，为该技术的应用提供重要支撑。