Discrimination of Unfermented Pu’er Tea Aroma of Different Years Based on Electronic Nose

In this paper, the unknown tea samples were discriminated in which year it is produced, by detecting Pu’er unfermented tea aroma of different years with electronic nose. Winmuster software has been adopted to analyze its principal component analysis (PCA), sensor difference contribution rate (loading), linear discriminant analysis (LDA) and partial least square method (PLS). The result showed that the distinction degree of PCA was 96.492%, which can separate the Pu’er unfermented tea aroma of different years. Loading analysis showed that the sensors of No.8 and No.9 made the greatest contribution to the first and second principal components of aroma. LDA analysis indicated that electronic nose can differentiate the aroma of unfermented Pu’er tea with the same type in different years. PLS results of discrimination agreed well with the reality by conducting random tea samples test. The study showed that electronic nose has odor sensors that the smell will be digital; it can not only discriminate aroma of unfermented tea, but also locate the year of unknown unfermented tea quickly.