Change of Aroma Components in Instant Baiyaqilan Tea Powder during Processing

In this study, the change of aroma components in instant Baiyaqilan tea powder during processing was investigated by sensory evaluation, gas chromatography-mass spectrometry (GC-MS) and odor activity value (OAV). The results showed that the over aroma profile and the types of aroma components in instant Baiyaqilan tea powder were similar at different stages of processing, while the aroma intensity and volatile components were significantly different. 3-Ethyl-2,5-dimethylpyrazine, hotrienol, methyl salicylate, safranal, geraniol, indole, β-damascenone, cis-jasmonone, geranyl acetone, trans-nerolidol and methyl jasmonate were found to make key contributions to aroma changes. The extraction process significantly increased the OAV of safranal, geraniol, indole, β-damascenone and cis-jasmonone. Disc separation, reverse osmosis and freeze drying significantly reduced the OAV of geraniol, indole, β-damascenone, cis-jasmonone, methyl jasmonate, trans-nerolidol, 3-ethyl-2,5-dimethylpyrazine and safranal. Moreover, ultrafiltration treatment removed tea polyphenol complexes, promoting the release of aroma volatile compounds combined with polyphenols and thus increasing the OAV of geraniol, indole, β-damascenone, cis-jasmonone and methyl jasmonate. This study clarified the aroma change during the processing of instant Baiyaqilan tea powder and showed that ultrafiltration treatment promoted the release of aromatic volatiles. This study can provide a theoretical basis for improving the processing of instant Baiyaqilan tea powder for improved aroma quality and the processing technology of instant tea.