炒青绿茶烟焦劣变因子及其检测方法

用毛细管气相色谱和色谱一质谱联用技术剖析了炒青绿茶中烟、焦异味物质的结构及其化学实质。研究结果首次证明,传统炒青绿茶中存在的烟气和焦味,在化学上具有本质的区别。焦味以吡嗪类化合物为主体;烟气则按其来源不同,分属于IH一茚、萘和愈创木酚等化合物。本研究提出了对上述特征化合物的检测方法,并对其形成条件和可能先质及生成途径进行了讨论,还初步拟定了烟焦物质的允许限量。

Smoky-burnt Odour in Roasted Green Tea and Its Analytical Methods

Smoky and burnt odours are the major problems which widely exist in the roasted green tea (RGT). The volatile constituents of smoky-burnt tea, which have not been studied prior to this report, have been analyzed with capillary gas chromatography and gas chromatography/mass spectrmetry. Experiments show that the burnt odour of tea mainly occurred in drying process, while the smoky odour occured in all steps with heat xreatment.Pyrazines and pyrroles are the chemical bases of burnt tea, and 2.5-dimethylpyrazine can be used as an indicatic compound of burnt odour. Guaiacol, naphthalene and indene are the chemical bases of smoky odour. The allowable amounts of these indicatic compounds have been set up primarily according to the results of instrumentic analysis and organoleptic evaluation.