ORIGINAL PAPER Study of herbal tea beverage discrimination method using electronic nose Jiaojiao Jin • Shanggui Deng • Xiaoguo Ying • Xiao Ye • Tingting Lu • Guohua Hui Received: 5 April 2014 / Accepted: 2 September 2014 / Published online: 23 September 2014 Ó Springer Science+Business Media New York 2014 Abstract Herbal tea, a kind of traditional Chinese bever- age, is widely used in China for its health benefits. This kind of tea beverage usually consists of several traditional Chi- nese medicines. So the taste of different herbal tea species varies a lot for their diverse components. In this paper, herbal tea discrimination method based on electronic nose (EN) is investigated. A laboratory developed EN, consisting of eight metal oxide semiconductor (MOS) gas sensors, is used in this study. EN responses to herbal tea samples at three temper- atures’ environment (20, 30, and 50 °C) are collected by a desktop. Principal component analysis (PCA) and stochastic resonance (SR) is used for EN measurement data processing. PCA results indicate that herbal tea samples are discrimi- nated more clearly with the increase of measurement tem- perature. The SR output signal-to-noise ratio (SNR) parameter is used for herbal tea discrimination. PCA method can not discriminate all herbal tea samples under different temperature. SR SNR method successfully discriminates all herbal tea samples under 20, 30, and 50 °C. Denglao herbal tea SNR eigenvalues have much difference from other tea samples. Higher measurement temperature leads to better herbal tea discrimination based on EN. Keywords Herbal tea  Temperature  Electronic nose  Stochastic resonance  Signal-to-noise ratio Introduction Herbal tea, or herbal tisane, a kind of traditional Chinese beverage, is widely used in China for its health benefits. The components of herbal tea beverage is brewed from the dried leaves, flowers, seeds, grasses, nuts, fruits, stems or roots of plant species rather than Camellia sinensis [1, 2]. This kind of tea usually consists of several traditional Chinese medicines, such as selfheal, chrysanthemum, honeysuckle, licorice and other compounds. So it has unique biological activities and health benefits that include health care, clearing summer-heat, anticancer, antimicro- bial, antidiabetic, antiinflammatory and antioxidant prop- erties [3, 4]. It usually tastes bitter or lightly sweet, and its color is typically black or dark brown. However, the taste of different herbal tea species is different for their diverse components. Usually, human sensory examination, chem- ical examination, and instrumental analysis methods are utilized in herbal tea quality evaluation. Human sensory examination evaluates herbal tea characteristics, such as color, odor, flavor, etc. But the evaluating results lack stability, reproducibility, etc. Chemical examination method is relatively precise. But this method is usually time-consuming and destructive. Instrumental analysis methods, including ICP-MS [5], Chemical fingerprinting methodology [6] and HPLC-ELSD [7], are usually utilized for herbal tea evaluation in-lab. Instrumental analysis methods can qualitatively and quantitatively characterize herbal tea. However, these methods are high cost, and time-consuming. Moreover, skilled operator is required to perform the instrumental analytical experiments. So there J. Jin  X. Ye  T. Lu  G. Hui (&) School of Computer Science and Information Engineering, Zhejiang Gongshang University, Hangzhou 310035, China e-mail: ghui@zjgsu.edu.cn J. Jin  X. Ye  T. Lu  G. Hui College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, China S. Deng  X. Ying College of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316000, China 123 Food Measure (2015) 9:52–60 DOI 10.1007/s11694-014-9209-0