提香方式对工夫红茶品质的影响

Effect of Aroma Enhancement Methods on the Quality of Congou Black Tea

以宜红茶为材料,采用热风、远红外、微波、光波、微波+光波组合(微波火力∶光波火力=67%∶33%)对其进行提香,通过感官品质评价、理化指标测定以及香气成分分析比较各方式的提香效果。结果表明,提香后红茶的甜香度增强,滋味鲜爽度提高,其中以远红外和微波提香效果尤为明显。理化指标测定结果表明,不同提香方式对水浸出物含量影响较小,对氨基酸含量及其组成、可溶性糖含量、茶多酚含量、儿茶素组成、茶黄素含量以及芳香成分有较大影响。与未提香组相比,所有提香处理均能提高茶叶中茶黄素含量,其中以光波处理(0.96 mg/g)最明显,其次是微波处理(0.86 mg/g)、远红外处理(0.85 mg/g)和热风处理(0.82 mg/g)。提香后茶叶中芳樟醇、苯甲醇等部分物质含量下降,苯甲醛、(E)-β-紫罗酮、反式-橙花叔醇等物质含量升高,同时还出现吡嗪、嘧啶等具有烘烤香的杂环化合物,芳香物质的变化利于茶叶甜香风味的形成。热风、远红外、微波提香处理的茶叶,香气组成中酮类、酯类、酸醚类和芳香类物质含量远高于其他处理。结合感官品质和理化分析得出远红外和微波处理是工夫红茶理想的提香方式。

The effects of different aroma enhancement treatments(hot air, far-infrared, microwave, light wave and microwave + light wave(microwave : light wave = 67%:33%)) on the sensory evaluation, physicochemical properties and aroma composition of Yihong black tea were studied. Sensory evaluation results showed that each of the treatments especially far-infrared and microwave irradiation could significantly strengthen the sweet aroma and fresh taste of black tea. Physicochemical analysis indicated that the different treatments had little effect on the content of water extractable substances in black tea, but greatly affected the composition of amino acids, aromatic compounds and catechins, and the contents of soluble sugar, tea polyphenols and theaflavins. Compared with the control, all these treatments could increase the content of theaflavins, and their effects followed the descending order: light wave(0.96 mg/g)> microwave(0.86 mg/g)>far-infrared(0.85 mg/g)> hot air(0.82 mg/g). The results also revealed that the treatments could decrease the amounts of linalool and benzyl alcohol and increase the amounts of benzaldehyde,(E)-β-lonone and(E)-trans-nerolidol, as well as lead to the formation of new heterocyclic compounds responsible for roasted aroma such as pyrazine and pyrimidine. Changes in each of the aromatic substances contributed to the sweet aroma of black tea. Furthermore, the contents of ketones, esters,ethers and aromatic components after hot air, far-infrared, and microwave treatments were significantly higher than in those subjected to any other treatments. Overall, far-infrared and microwave treatments were considered to be more suitable for aroma enhancement of Congou black tea.