Identification of the aroma-active compounds in Longjing tea characterized by odor activity value, gas chromatography-olfactometry, and aroma recombination

Volatile compounds in the three Longjing tea were analyzed by gas chromatography-mass spectrometry with method of solid phase microextraction-gas chromatography. Furthermore, aroma-active compounds of three Longjing tea were analyzed by gas chromatography-olfactometry and odor activity value. However, the kinds of aroma-active compounds identified from those two methods were different. The results showed that dihydroactinidiolide (aroma intensity = 9.1-9.2), (Z)-nerolidol (aroma intensity = 8.4-8.8), benzyl alcohol (aroma intensity = 8.1-8.4), and epoxylinalool (aroma intensity = 8.1-8.5) presented the highest aroma intensity in three green tea samples. While geraniol (422.4-2508.3), epoxylinalool (601.5-1033.9), (Z)-nerolidol (235.5-559.3), 2-ethyl-3,5-dimethylpyrazine (328.0-420.6), -ionone (227.7-387.3) presented higher odor activity values than other compounds. Thus, this study uses recombination aroma models to identify selected important aroma-active compounds from gas chromatography-olfactometry and odor activity value and verifies their effectiveness to identify the aroma profile characterization of three Longjing tea samples using electronic nose analysis and sensory evaluation. The radar plot of electronic nose analysis tallied with sensory evaluation indicated that the odor activity value-based aroma models were more similar to the original Longjing tea aroma than gas chromatography-olfactometry-based models.