基于电子鼻技术对不同季节山东绿茶香气的分析

Analysis of Aroma of Shandong Green Tea in Different Seasons Based on Electronic Nose Technology

本研究以山东茶区春、夏、秋季绿茶为材料,运用感官审评对其香气特征进行评价,同时利用电子鼻技术对其香气成分组成进行分析。感官审评表明:春、夏、秋季绿茶分别呈现清香、栗香和花香,春茶综合得分最高,品质最佳。电子鼻分析表明:在主成分分析(Principal Component Analysis,PCA)中,第一主成分PC1的贡献率为74.22%,第二主成分PC2的贡献率是24.27%,总贡献率为98.49%,在线性判别分析(Linear Discriminant Analysis,LDA)中,第一主成分PC1的贡献率为96.68%,第二主成分PC2的贡献率为3.30%,总贡献率为99.98%,两者均可以将不同季节绿茶区分开来;从传感器区分贡献率分析(Loadings)分析可以看出,传感器7、9、2、10即硫化合物、芳烃化合物、硫的有机化合物、氮氧化物以及烷类和脂肪族,对区分不同季节绿茶香气的贡献较大,这几类成分可能是影响不同季节山东绿茶香气差异的主体成分。研究结果为山东不同季节绿茶的判断提供了一种科学、快速的方法。

In this study,the aroma characteristics of spring,summer and autumn green tea in Shandong tea area were evaluated by sensory evaluation,and the composition of aroma components was analyzed by electronic nose technology.Sensory evaluation showed that:spring,summer and autumn green tea presented fragrance,chestnut fragrance and flower fragrance respectively.Electronic nose analysis showed that in Principal Component Analysis(PCA),the contribution rate of the first principao component PC1was 74.22%,and that of the second principal component PC2 was 24.27%,with a total contribution rate of 98.49%.In lineat discriminant analysis(LDA),the contribution rate of the first Principal Component PC1 was 96.68%,and that of the second principal component PC2 was 3.30%,with a total contribution rate of 99.98%.The aroma of green tea in different seasons could be distinguished by both PCA and LDA analysis.From the analysis of loadings,it can be seen that sensors 7,9,2 and 10,namely sulfur compounds,aromatic compounds,organic compounds of sulfur,nitrogen oxides,alkanes and aliphatic groups,contributed a lot to distinguish the aroma of green tea in different seasons.These components might be the main components that influenced the aroma of Shandong green tea in different seasons.A scientific and rapid method for the judgment of green tea in different seasons in Shandong Province could be provided by this study.