香葱分段式变温催化红外干燥的特性及品质研究

Characteristics and Quality of Chinese Chives Dried by A Temperature-segmented Catalytic Infrared System

摘要:

为提高脱水香葱品质、缩短干燥时间、降低能耗，本研究采取了红外分段式变温加热技术。利用单板和双板进行高温加低温结合的工艺，对香葱不同干燥模式下干燥特性、色泽和复水比进行研究。研究表明，单板模式下第一阶段80、90 ℃分别处理12、6 min能够去大量水分，水分比分别降至0.38和0.12，第二阶段的低温干燥60、70 ℃干燥速率没有明显区别，总干燥时间为17~18 min。双板组合条件下，第一阶段60~90 ℃在2~3.5 min能够快速去除约一半水分，第二阶段温度为70 ℃组总干燥时间为19~23 min，60 ℃总干燥时间为27~29 min。组合干燥模式解决了干燥过程中因高温而造成的色泽焦变的现象。通过对比不同组合干燥后香葱的色泽变化和复水比可以看出，经单板+单板的变温组合处理的产品具有较高的复水比，而双板+单板的变温组处理的产品够具有较优的色泽。

Abstract:

To improve the quality of dehydrated Chinese chives, shorten the drying time and reduce energy consumption, temperature-segmented infrared heating technology was adopted in this research. The drying characteristics, color and rehydration ratio of chives dried by different methods were studied via the combination of high temperature and low temperature using single- and double- plates. The results showed that a large amount of water were removed in the first stage of single-plate drying mode at 80 ℃ for 12 min and 90 ℃ for 6 min, respectively, with the water ratio down to 0.38 and 0.12 respectively. In the second stage, no significant difference in the drying rate for the low-temperature drying at 60 and 70 ℃, with the total drying time ranging in 17~18 min. In the double-plate mode, about half of the moisture was removed quickly in the first stage of drying at 60~90 ℃ for 2~3.5 min, while the second stage of drying was performed at 70 ℃ for 19~23 min or at 60 ℃ for 27~29 min. The combined drying mode eliminated color darkening caused by high-temperature drying. By comparing the color change and rehydration ratio of chives dried by different combinations of processes, one may conclude that the dehydrated chive product treated by single-single temperature variable drying mode had a higher rehydration ratio, while the product treated by double-single temperature variable drying modes had a better color.