热泵干燥对黄金奇异果维生素C含量的影响及其干燥动力学模型拟合

Effects of heat pump drying on the vitamin C content of yellow flesh kiwifruit and its drying dynamics model fitting

中文关键词:  热泵  干燥  黄金奇异果  VC  动力学

英文关键词:heat pump  drying  yellow flesh kiwifruit  vitamin C  dynamics

中文摘要:

      目的 探究热泵干燥对黄金奇异果果片干燥特性的影响, 并建立动力学模型。方法 采用不同的干燥温度(50、60、70℃), 前处理方式(盐处理、热烫、切片厚度)干燥果片, 通过测定和计算干燥特性指标, 采用Page干燥模型对干燥过程进行拟合, 构建干燥动力学方程。结果 干燥温度越高, 果片的维生素C保留率越低, 在干燥温度恒定为50℃时, 切片厚度5 mm、0.3% (m/V)亚硫酸氢钠处理1 h、热烫时间3 s时的果片维生素C保留率最好。果片的水分比随干燥时间的延长呈现指数型下降趋势; 切片厚度在5 mm、热烫时间3 s时, 黄金奇异果片的Ea为25.7709 kJ/mol, 即热泵干燥黄金奇异果片的1 mol水分所需的最低能量为25.7709 kJ; 黄金奇异果片的热泵干燥试验值与Page模型的拟合程度较好, 模型的拟合优度R2=0.9990, 卡方误差2=0.000086、方差分析的F为37410.71、P<0.01, 说明试验值与拟合值间具有显著的相关性。结论 Page模型适合用于描述黄金奇异果片的热泵干燥过程, 能较好为黄金奇异果果片的水分变化规律提供参考。

英文摘要:

      Objective To investigate the effect of heat pump drying on the drying characteristics of yellow flesh kiwifruit slices and establish a dynamic model. Methods Different drying temperatures (50, 60, 70℃) and pre-treatment methods (salt treatment, blanching, slice thickness) were used to dry fruit slices. By measuring and calculating drying characteristic indicators, the Page drying model was used to fit the drying process and construct a drying kinetics equation. Results The higher the drying temperature, the lower the vitamin C retention rate of fruit slices. When the drying temperature was constant at 50℃, the vitamin C retention rate of fruit slices was the best when the slice thickness was 5 mm, 0.3% (m/V) sodium bisulfite is treated for 1 hour, and the blanching time was 3 seconds. The moisture ratio of fruit slices showed an exponential downward trend with the extension of drying time; When the slice thickness was 5 mm and the blanching time was 3 s, the Ea of yellow flesh kiwifruit slices was 25.7709 kJ/mol, which meaned the minimum energy required for 1 mol of water in the heat pump drying of yellow flesh kiwifruit slices was 25.7709 kJ; the heat pump drying test values of yellow flesh kiwifruit slices showed a good fit with the Page model, with a goodness of fit of r2=0.9990 and a chi square error of 2=0.00086. The F-value of the analysis of variance was 37410.71, with P<0.01, indicating a significant correlation between the test values and the fitted values. Conclusion The Page model is suitable for describing the heat pump drying process of yellow flesh kiwifruit slices and can provide a good reference for the moisture change law of yellow flesh kiwifruit slices.