Characterization of the aromatic profile in “zijuan” and “pu-erh” green teas by headspace solid-phase microextraction coupled with GC-O and GC-MS
Aroma volatiles from zijuan and pu-erh green teas were extracted by headspace solid-phase microextraction (HS-SPME). They were then characterized and identified using gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). The conditions of HS-SPME, including fiber selection and optimization of sampling conditions, have been previously investigated. Under optimal conditions, 51 and 42 aroma-active compounds were detected and characterized in zijuan and pu-erh green tea samples, respectively. Alcohols, ketones, and hydrocarbons were qualitatively the most dominant aroma-active compounds in zijuan and pu-erh green teas. The aroma-active compounds with similar sensory descriptors were grouped into the same category, and the sum of individual aroma intensity values within each category showed that the “floral” aroma, “woody” aroma, and “fruity” aroma in both zijuan and pu-erh green teas were the major aroma categories. These aroma notes were closely related to the characteristics of green tea aroma and its sensory perception.