摘要
采用同步热分析仪研究12份福建乌龙茶茶样的热分解过程.试验条件为:茶样由室温以10℃·min-1匀速升温至600℃,气氛为空气,铝坩埚加盖(盖上钻1 mm的孔).结果表明:茶叶的热分解过程分为5个失重阶段:1室温至100℃左右主要为脱水阶段;2100-226℃为茶叶挥发物逸出阶段;3226-345℃为变味热分解阶段;4345-482℃为碳化阶段;5482-600℃为燃烧阶段.茶叶具有相似的失重过程,差示扫描量热法(DSC)曲线体现茶叶的特征,阶段2主要体现茶叶内含物的品质特征,阶段345主要体现茶叶的纤维素、半纤维素和木质素及粗蛋白、粗脂肪和无机盐等其他物质的含量特征,可反映不同品种、季节和加工工艺茶叶组成的差异.因此同步热分析可作为一种初步的鉴别方法.
10 kinds of Fujian oolong tea were studied by STA449 F3 - Jupiter simultaneous thermal analyzer （ NETZSCH STA449 F3-Jupiter）. The test conditions： from room temperature to 600 ℃, heating rate of 10 ℃ ·min^-1 , atmosphere of air, aluminum crucible plus with 1 mm diameter hole cover. The results showed that, the pyrolysis process could be divided into five stages, inclu- ding drying stage of the temperature from room to 100 ℃ ; escape of volatiles stage of 226 ℃ ; flavor changing stage of the tempera- ture from 226 ℃ to 345 ℃ ; carbonization pyrolysis stage of the temperature from 345 ℃ to 482 ℃ ; thermogravimetry （TG） and mi- crothermogravimetry （DTG） curves of tea are similar, but differential scanning calorimetry （DSC） curves are different, they can re- flect the characteristics of tea. The second stage reflects the inelnsion quality, last 3 stages reflect the content of hemicellulese, cel- lulese, lignin and other substances. They also reflect the difference of inclusions of different varieties, season and processing. Sim- ultaneons thermal analysis of tea can also be used as a preliminary identification method.
出处
《福建农林大学学报（自然科学版）》
CSCD
北大核心
2014年第5期465-469,共5页
Journal of Fujian Agriculture and Forestry University:Natural Science Edition
基金
国家自然科学基金资助项目(31270735)
中国乌龙茶产业协同创新中心(培育)专项(2013-51)
关键词
乌龙茶
热分解
热重(TG)
微热重(DTG)
差示扫描量热(DSC)法
Oolong tea
thermal decomposition
thermogravimetry （TG）
mierothermogravimetry （DTG）
differential scanning calorimetry （DSC）
