参数对高水分加工食品真空冷却效果的影响

Effect of parameters on the cooling effect of high moisture processed food during vacuum cooling

搭建了真空冷却实验平台,研究冷却压力、物料初始温度、物料相对表面积以及物料堆叠方式对豆腐真空冷却过程中冷却时间和失水率的影响。结果表明,冷却压力越低,所需冷却时间越短,但质量损失越大。当初始温度较高时(>40℃),豆腐的温度存在快速降低阶段,而初始温度较低时,温度的降低曲线比较平缓,随时间近似呈线性降低;失水率随初始温度的升高,呈现先快速增加后趋于平缓的规律。另外,物料相对表面积越大,所需冷却时间和失水率均会显著降低。不同堆叠方式对豆腐的冷却效果不同,斜向堆叠方式的冷却效果最佳;随着堆叠数量的增加,横向堆叠和纵向堆叠的冷却时间和失水率均会显著增加,但斜向堆叠与它们不同的是其失水率基本保持不变。

In this paper,a vacuum cooling experiment device was set up to study the effects of cooling pressure,initial temperature,relative surface area and stacked forms of materials on the cooling time and water loss rate of tofu during the vacuum cooling.The results show the lower the cooling pressure,the shorter the cooling time,but the greater the mass loss.When the initial temperature is higher(>40℃),the temperature of tofu has a rapid decline stage,while the initial temperature is lower,the decrease curve of temperature is relatively gentle and approximately linear with time;with the increase of initial temperature,the water loss rate first increases rapidly and then changes smoothly.In addition,with the increase of the relative surface area of the material,the cooling time and the water loss rate will be reduced significantly.The cooling effect of stacked forms on tofu was studied,and the oblique stacked form is the best;with the increase of the number of tofu slices,the cooling time and water loss rate of the horizontal stacked form and the vertical stacked form will increase significantly,but the water loss rate of the oblique stacked form will remain basically the same.