中文摘要：

冷冻浓缩是一种可望替代或部分替代传统蒸发浓缩或反渗透浓缩、用于对食品溶液或生物溶液进行浓缩或预浓缩的特殊方法。然而在冷冻浓缩的实践中发现,冰层对制冷面的包覆,即冰淤塞,即使换热面是在很小的过冷下度下（如过冷温度只有0.2℃）仍然是不可避免的。冰淤塞使制冷面的传热系数显著下降。本研究还发现冰晶在制冷面上直接释放结晶潜热使制冷面的温度跃升,即热响应,标志着制冷面上冰晶开始生成。随后,薄冰层铺展开并最终覆盖整个制冷面。覆盖完成可用金属表面与溶液之间交流阻抗的变化及增加来表征。

英文摘要：

Freeze concentration is an excellent alternative to conventional evaporation and reverse osmosis for concentration or pre-concentration of many liquid foods.However,the build-up of an ice layer on the cooler surface,which is known as ice fouling and unavoidable even at a low degree of supercooling,e.g.around 0.2°C.This significantly reduces the heat-extraction rate and increases the cost of freeze concentration.In this study,the onset time of ice fouling on the subcooled metal surface can be indicated by the step increase of the surface temperature due to the release of the latent heat of ice fusion.A method was developed to indicate the ice fouling induction time on the cooler surface according to an increase of the AC impedance between the solution and the cooler surface.