低温真空—热风联合干燥绿茶最佳水分转换点确定试验研究报告

Study experience of combining low-temperature vacuum and hot-air drying to determine optimal transition point of water on green tea

为了获得高品质的绿茶产品,本研究对绿茶的干燥工艺进行创新,使用低温真空—热风联合干燥工艺对绿茶进行干燥。即将揉捻好需干燥的绿茶,先在低温真空环境下脱出部分水分,保护好绿茶的叶绿素,固定茶叶外形色泽;再以一定的湿热条件发展香气,使干燥后的绿茶具有绿润的色泽和较高的香气。试验结果表明:使用联合干燥工艺干燥绿茶,首先用低温真空干燥工艺将茶叶的水分降至18%-28%,然后再利用热风干燥机干燥至水分≤6%左右,所得的绿茶外形色泽绿润、香气高、滋味醇厚。综合品质高于传统的热风干燥。

In order to obtain high-quality green tea products, we innovated a drying process for green tea, that is the technology of low-temperature vacuum combining with hot-air drying. After finishing the process of tea rolling, which is dehydrated a part of water to protect chlorophyll and fix appearance of the tea in a low-temperature vacuum environment, then develop aroma in a damp and hot condition, and to abtain green tea with excellent green color and high aroma. The results showed that when water of the tea was dehydrated to 18%-28% in low-temperature vacuum condition and then was dried to less than 6% in hot air condition, we obtained green tea with better green color, higher aroma, and mellower taste. The comprehensive quality is higher than that with traditional hot-air drying.