Abstract: In order to explore the migration of moisture and the variation in aroma components during the scenting of jasmine tea, tea samples before scenting, before heat release, before flower pick-out and after drying were analyzed for water distribution by low-field nuclear magnetic resonance (NMR), and the composition and content of aroma components in these samples were determined by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The results showed that the moisture content of jasmine tea was significantly different at different stages of scenting, and all tea samples except tea base before scenting exhibited the signal peaks of bound water, immobilized water and free water. Bound water was the major water state, and the proportion of peak area of bound water tended to increase initially and then decrease, and was higher than that before scenting. The proportion of peak area of immobilized water decreased first and then increased, and was lower than that before scenting. The?proportion of peak area of free water was the lowest and not found before scenting, and presented a trend of first decreasing and then increasing during scenting. A total of 75 aroma components were identified in the jasmine tea scenting process, including alcohols, esters, alkenes and aldehydes. The aroma released from jasmine flowers was adsorbed by tea, so the content of aroma components increased in jasmine tea after drying. Among them, the content of esters was the highest (9.721 μg/g), followed by alcohols (3.854 μg/g), and alkenes (3.377 μg/g), and the number of alkenes was the largest (26). The score for aroma quality of jasmine tea increased, then decreased and increased again during scenting, and was higher than that before scenting, which was more suitable than aroma index for evaluating the aroma quality of jasmine tea. Correlation analysis showed that the peak areas of bound water and immobilized water had a positive correlation with the relati contents of alcohols, and the peak area of free water had a significantly negative correlation with the contents of esters but a significantly positive correlation with the contents of alkenes. The results provide a theoretical basis for enriching the knowledge about the aroma adsorption mechanism of jasmine tea and regulating the processing parameters of jasmine tea.

Key words: jasmine tea; scenting; moisture state; aroma components; correlation