超声场作用下胡萝卜渗透脱水质量传递规律研究

以胡萝卜为原料,探讨了在超声场作用下,浸泡液浓度、渗透时间、温度等因素对胡萝卜—蔗糖溶液固液体系传质速率的影响.通过实验得出了胡萝卜失水率及固形物得率,由此确定了不同条件下胡萝卜失水率及固形物得率常数,基于质量守恒定律建立了胡萝卜渗透脱水传质模型.结果表明:当温度保持不变时,物料的失水率及固形物得率常数随蔗糖溶液浓度的增加而增加,同时温度对高浓度渗透液的影响比低浓度的大;当渗透液浓度不变时,随着反应温度增加失水率常数增加,固形物得率常数降低.失水率随时间变化与可渗出但仍保留在物料中的含水率呈正比线性关系.

Transfer rule of osmotic dehydration of carrots under ultrasound treatment

Using carrots as a raw material,we explored the effects of solute liquid concentration,osmotic time,and temperature on the mass transfer rate of a solid-liquid system containing plant material and liquid sucrose.Dehydration and solid gain rates for carrots were obtained from experiments.With that data,we determined the dehydration rate constant and the solid gain rate constant of carrots under varied conditions.A mass transfer model of carrot osmotic dehydration was established based on the mass conservation law.The results showed that,at a constant temperature,the constants for dehydration rate and solid gain rate of carrots increase with the increasing concentration of the sucrose solution,whereas the temperature has more impact on a highly-concentrated sucrose solution;at a constant sucrose concentration,the dehydration rate constant increases and the solid gain rate constant decreases with an increase of temperature.The dehydration rate varies with time,but is directly proportional to the quantity of water that remains available to permeate out.