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), β-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.

E-jiao (Colla Corii Asini, CCA) has been widely used as a healthy food and Chinese medicine. Although authentic CCA is characterized by its typical sweet and neutral fragrance, its aroma components have been rarely investigated. This work investigated the aroma-active components and antioxidant activity of 19 CCAs from different geographical origins. CCA extracts obtained by simultaneous distillation and extraction were analyzed by gas chromatography–mass spectrometry (GC–MS), gas chromatography–olfactometry (GC–O) and sensory analysis. The antioxidant activity of CCAs was determined by ABTS and DPPH assays. A total of 65 volatile compounds were identified and quantified by GC–MS and 23 aroma-active compounds were identified by GC–O and aroma extract dilution analysis. The most powerful aroma-active compounds were identified based on the flavor dilution factor and their contents were compared among the 19 CCAs. Principal component analysis of the 23 aroma-active components showed 3 significant clusters. Canonical correlation analysis between antioxidant assays and the 23 aroma-active compounds indicates strong correlation (r = 0.9776, p = 0.0281). Analysis of aroma-active components shows potential for quality evaluation and discrimination of CCAs from different geographical origins. Graphical Abstract