香蕉冻干加工的水蒸气扩散系数  

Water Vapor Diffusion Coefficient of Freeze-dried Banana Slices

作　　者：王宏宇[1] 张绍志[1] 虞效益[1] 陈光明[1] 

机构地区：[1]浙江大学制冷与低温研究所,浙江杭州310027

出　　处：《食品科学》2013年第13期66-70,共5页Food Science

基　　金：中央高校基本科研业务费专项(2012QNA4008)

摘　　要：香蕉片冷冻干燥可以获得高质量的产品。水蒸气在干燥区内有效扩散系数的大小影响到搁板温度或辐射板温度的设定,是影响冻干过程快慢的关键参数之一。根据冷冻香蕉片一次干燥阶段的质量变化曲线,拟合得到水蒸气在干燥区内的有效扩散系数,研究香蕉成熟度、预冻速率、护色剂等因素对有效扩散系数的影响。结果表明:水蒸气有效扩散系数在1.0×10-4～3.5×10-4m2/s之间,预冻速率的影响最大,成熟度的影响较小,使用护色剂以后有效扩散系数则略有减小。Freeze drying of banana slices can offer high quality banana products.The diffusion coefficient of water vapor in the dry area influenced the setting of the shelf temperature or the radiant plate temperature,which was one of the key factors affecting the lyophilization process.According to the weight changes of banana slices during freeze drying,the effective diffusion coefficient of water vapor in the dried zone was obtained.The impacts of maturity degree,precooling velocity and color fixative on the value of diffusion coefficient were examined.Results showed that the effective diffusion coefficient of water vapor ranged between 1.0 × 10-4 m2/s and 3.5 × 10-4 m2/s.The impact of precooling velocity was the largest while maturity degree had the least effect.Addition of color fixative caused a slight reduction of the diffusion coefficient.

关 键 词：香蕉片 冷冻干燥 水蒸气 扩散系数 

分 类 号：TS255.3[轻工技术与工程—农产品加工及贮藏工程]