不同萎凋工艺云南红茶的香气差异分析

Analysis of the Aroma Differences of Yunnan Black Tea Subjected to Different Withering Processes

该研究以云南大叶种鲜叶为材料,运用感官审评和电子鼻技术对7种不同萎凋工艺云南红茶的香气特征和成分进行分析。电子鼻分析表明:在主成分分析(PCA)中,干茶香气总贡献率为98.423%、茶汤香气总贡献率为99.948%、叶底香气总贡献率为99.948%,且干茶香气较茶汤香气和叶底香气更能够较好地区分不同萎凋工艺的云南红茶;在传感器区分贡献率分析(Loadings)中,W1S(甲基类)、W1C(芳香成分、苯类)、W2S(醇类、醛酮类)和W5S(氮氧化合物)在红茶香气区分中起主要作用,其可能是影响不同萎凋工艺制成云南红茶香气差异的主体成分。感官审评结果显示WM7[室内自然萎凋,24 h,(17±2)℃,相对湿度70%±5%,摊叶厚度2 cm]制作成的大叶种云南红茶,汤色橙红明亮,香气甜香浓郁,滋味醇厚有花果香,综合感官品质最好。

In this study,the fresh leaves of the Yunnan large-leaf species were taken as the material,the aroma characteristics and components of Yunnan black teas subjected to seven different withering processes were analyzed by sensory evaluation and electronic nose technique.The electronic nose analysis showed that the total contribution rates were 98.423%for the dry tea aroma,99.948%for the tea soup aroma,and 99.948%for the leaf base aroma in the principal component analysis(PCA),with the dry tea aroma being more useful for distinguishing Yunnan black teas subjected to different withering processes compared with the tea soup aroma and leaf base aroma.In the sensor differential contribution analysis(loadings analysis),W1S(methyl group),W1C(aromatic components,benzene),W2S(alcohols,aldehydes and ketones)and W5S(nitrogen oxides)played major roles in the aroma differentiation of black tea,and they may be the main components causing the aroma differences of Yunnan black teas subjected to different withering processes.The results of the sensory evaluation showed that the WM7 large-leaf Yunnan black tea(natural withering indoors,24 h,17℃±2℃,relative humidity 70%±5%,leaf thickness 2 cm)had the best overall sensory quality with an orange-red bright soup color,sweet and rich aroma,mellow taste and floral and fruit aromas.