摘要
研究南瓜片在不同温度（60℃、70℃和80℃）下的热风干燥特性。采用Fick扩散模型对南瓜片的水分质量传递进行描述，并计算水分扩散系数。结果表明，热风温度越高，干燥速率越快，干燥过程发生在降速阶段。水分扩散系数随温度的升高而增大，在试验温度范围内，有效扩散系数值在5．4150＆#215;10-10～1．0077＆#215;10-9 m2/s之间。温度对水分扩散的影响可用Arrhenius关系方程来表示，其决定系数为0．997。南瓜的活化能值为30．33kJ/mol。采用12种数学模型对南瓜片的薄层干燥过程进行描述，通过比较水分比的试验值和预测值之间的统计参数---决定系数（R2）、卡方（X2）和均方根误差（RMSE），发现Modified Henderson and Pabis模型最适宜于描述南瓜片的薄层干燥过程，该模型能较准确地表达和预测南瓜热风干燥过程的水分变化规律。
Air-drying characteristics of pumpkin slices were investigated under air temperatures of 60℃, 70℃and 80 ℃.Moisture transfer from the test samples was described by applying the Fick’s diffusion model and the effective diffusivity was calculated.Results indicated that the drying rate increased with drying air tem-perature and drying took place in the falling rate period.The effective diffusivity was found to increase with the drying air temperature and ranged between 5.41 50 ＆#215;1 0 -10 ~1 .0077 ＆#215;1 0 -9m2/s.The effect of temperature on diffusivity could be expressed by an Arrhenius type relationship with a high R2 of 0.997.The activation energy of pumpkin was found to be 30.33 kJ/mol.Twelve mathematical models for describing the thin-layer drying process of pumpkin slices were investigated.The mathematical models compared according statistical parame-ters such as the coefficient of determination （R2 ）,reduced chi-square （X2 ）and root means square error （RMSE）between experimental and predicted moisture ratios.In conclusion,the Modified Henderson and Pabis model is the most suitable model for describing the thin layer drying process of pumpkin slices and could exact-ly describe and predict the moisture dynamics of pumpkin slices during hot air drying process.
出处
《包装与食品机械》
CAS
2014年第1期23-27,共5页
Packaging and Food Machinery
关键词
南瓜
干燥模型
有效扩散系数
活化能
pumpkin
drying model
effective diffusivity
activation energy
