Abstract: The tea shoots of cultivars Zijuan, Zhongcha 108 and Wuniuzao, with high, middle and low resistances to the tea green leafhopper were collected and cultured in water. Every tea shoot was introduced by 3 leafhoppers with 2 day old, and the shoots suffered for 0, 12, 24, 36, 48 and 60 h respectively. After being damaged, the tea shoots were plucked to produce the steamed tea samples. The taste, aroma and color of tea soup of the steamed tea samples were detected by electronic tongue, electronic nose and colorimeter respectively. The leafhopper-damaged duration was significantly and positively correlated with sourness value (SRS) and saltiness value (STS) of tea soups of three cultivars. The leafhopper-damaged duration on cultivar Zijuan was positively correlated with sourness value (BRS), and significantly negatively correlated with both umami value (UMS) and sweetness value (SWS). The leafhopper-damaged duration on cultivar Zhongcha 108 was positively correlated with BRS, and significantly positively correlated with both UMS and SWS. The leafhopper-damaged duration on cultivar Wuniuzao was significantly and negatively correlated with BRS, UMS and SWS respectively. Data acquired by electronic tongue was analyzed by the principal component analysis (PCA) and the soft independent modeling of class analogy (SIMCA). In both PCA and SIMCA coordinate systems, the six leafhopper-damaged tea samples distributed linearly for each cultivar. Data by electronic nose was also analyzed by PCA and SIMCA, then by PCA or SIMCA coordinate system, the 6 leafhopper-damaged tea samples also distributed linearly for cultivars Zijuan and Zhongcha108, but not Wuniuzao. The colorimeter results revealed that during the time course of damage from 0 h to 60 h, the chroma of yellow-green of tea soups of cultivars Zijuan and Wuniuzao deepened, and the brightness of tea soup of cultivar Zhongcha 108 obviously fell. It was considered that electronic tougue and electronic nose may effectively discriminate resistant cultivar from susceptible cultivar, and differentiate damage degree in tea samples.

Key words: electronic tongue, electronic nose, Empoasca onukii Matsuda, taste and aroma and color, colorimeter