Effects of Different Drying Methods on Volatile Components of Jasmine Tea

To study the effect of different drying methods on volatile components of jasmine tea, headspace solid phase microextraction combined with gas chromatography-mass spectrometry and electronic nose technology were used for quantitative and qualitative analysis of the volatile compounds in jasmine tea dried by four methods, including heat pump drying, hot air drying, microwave drying and vacuum-freeze drying. The results showed that, the top three response values of electronic nose sensors were W1W, W2W and W5S. Under different drying treatments, it can better reflect the differences in volatile substances in jasmine tea. The results of HS-SPME-GC-MS showed that a total of 96 volatile components (alcohol esters, aldehydes, ketones, olefins and other classes) were identified in jasmine tea by four different drying methods. Among these components, the species of olefin compounds were the most with the amount of 37. The total amounts of the volatile components in jasmine tea by freeze-drying were the most abundant with a relative content of 47.382 μg/g, followed by heat pump drying with a relative content of 44.429 μg/g. And the relative contents of olefin and alcohols were higher than other components. The JTF (jasmine tea fragrance) index of jasmine tea was the highest with a amount of 4.766 by heat pump drying. Therefore, HS-SPME-GC-MS combined with electronic nose technology could be used to distinguish the quality of jasmine tea by different drying methods, and would provide theoretical reference for the selection of drying methods in jasmine tea production.