Comparison of different aroma-active compounds of Sichuan Dark brick tea ( Camellia sinensis ) and Sichuan Fuzhuan brick tea using gas chromatography–mass spectrometry (GC–MS) and aroma descriptive profile tests

Sichuan dark brick tea ( Camellia sinensis ) and Sichuan Fuzhuan brick tea have significantly different aroma characteristics although both of them have almost the same processing methods. Thus, these two types of tea were used as the research materials to determine the differences in their aroma compounds. The volatile compounds in the two types of tea were identified and quantified by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS), results showed that they both had 37 common volatile compounds. Then the aroma-active components were identified by odour activity value (OAV). It was found that SFBT had 20 aroma-active components, of which β-ionone had the largest OAV (199547.72). SDBT has 21 aroma-active ingredients (including all 20 aroma-active components of SFBT), of which β-ionone again has the largest OAV (114800.66). Finally, the aroma profile differences between the two tea samples were studied by aroma profile tests, and the results showed that the main aroma differences of SDBT and SFBT were caused by β-ionone, epoxydihydrolinalool II, methyl salicylate, geranylacetone, nerolidol, benzaldehyde, benzyl acetate, nonanal, trans , trans -2,4-heptadienal and 1-octen-3-ol, in addition, defined SFBT’s ‘fungi flower aroma’ and SDBT’s ‘aged fragrance’ from the level of aroma monomer.