预处理方式及干燥温度对养心菜热风干燥特性与品质的影响

为了解决养心菜干燥生产过程中干燥时间长、能耗高、干燥效率低等问题，本文研究了不同预处理方式（切段、压扁、压扁+切段）、温度（60、70、80 ℃）对养心菜热风干燥特性的影响，以及全株、茎、叶干燥特性的差异，建立干燥过程数学模型，并分析不同预处理方式、热风温度对养心菜品质的影响。结果表明:提高热风温度以及进行压扁、压扁+切段预处理可以显著提高干燥速率（P<0.05），压扁+切段处理下热风温度80 ℃干燥时间仅为70 ℃、60 ℃的47%、21%；热风温度80 ℃下压扁、压扁+切段处理干燥时间仅为未处理组的40%、35%；另外压扁+切段预处理可以大幅降低茎秆干燥时间，提高茎叶干燥均匀性。Weibull干燥模型与试验数据的拟合度均高于0.99。提高热风温度以及进行预处理有利于减少全株养心菜可溶性蛋白质损失，但会造成VC含量的下降。在热风温度80 ℃、压扁+切段预处理下可溶性蛋白含量最高，达到6.577 gprot/L；而VC含量在热风温度80 ℃、切段预处理下最高，达到8.503 mg/100 g。在相同干燥条件下，茎、叶单独干燥后可溶性蛋白含量均高于整株。热风温度80 ℃与压扁+切段预处理为养心菜最合适的干燥工艺。本研究的结果可以为养心菜干燥工艺的优化提供理论基础，有利于提高其干燥加工的效益。

Effects of Physical Pretreatment Methods and Hot Air Temperatures on the Hot Air Drying Characteristics and Quality of Yangxincai (Sedum aizoon L.)

In order to solve the problems of long drying time, high energy consumption and low drying efficiency, the drying experiment was conducted which study the effects of physical pretreatment methods (flattening, cutting, flattening + cutting) and hot air temperatures (60, 70, 80 ℃) on the drying characteristics of the whole plant, stem and leaf of Yangxincai. The drying model was established. The effects of different treatments was analyzed on the quality of Yangxincai . Experiment results showed that increasing hot air temperature and conducting flattening, flattening + cutting pretreatment could increase the drying rate and lower the drying time (P<0.05). Under flattening + cutting treatment, the drying time of hot air at 80 ℃ was only 47%, 21% of that at 70, 60 ℃, respectively. Under hot air temperature 80 ℃, the drying time of flattening and flattening + cutting treatment was only 40%, 35% of untreatment. The fitting degree of Weibull model was higher than 0.99 with experiment data. Increasing the hot air temperature and conducting physical pretreatment could reduce the soluble protein loss and make VC concentration decrease. The content of soluble protein was the highest, reaching 6.577 gprot/L under the hot air temperature 80 ℃ and flattening + cutting treatment. The content of V_C reached the highest level of 8.503 mg/100 g under the hot air temperature 80 ℃ and cutting treatment. Under the same treatment conditions, the content of soluble protein in dried stems and leaves was higher than the whole plant. The best drying method of Yangxincai was hot air temperature 80 ℃ and flattening + cutting treatment. The results of this study can provide a theoretical basis for the optimization of the drying process of Yangxincai, and improve the economic benefit of drying process.