Methyl jasmonate-induced changes of flavor profiles during the processing of green, oolong, and black tea (Frontiers Plant Sci)

Tea quality depends on the product’s taste and aroma, which are provided by phenolic and volatile compounds respectively.  Here, Shi et al. analyzed changes of volatile and amino acid (AA) profiles in fresh tea leaves (Camellia sinensis L.) and during the processing of three tea products (green, oolong and black) after after preharvest methyl jasmonate (MeJa) treatment. By a descriptive sensory evaluation, all treated teas showed a slightly increased flowery aroma that is associated with good quality. Volatile analysis by Gas Chromatography-Mass Spectrometry (GC-MS) showed an increase in 2-phenylethyl alcohol and benzyl alcohol which are related to the flowery aroma. Amino acid changes depended on the type of processing, with a decrease in aromatic AA during tea processing which correlates with a direct conversion of tryptophan- and phenylalanine-derived volatile compounds. The authors concluded that MeJa treatment induces changes in volatiles and amino acids levels by affecting the lipoxygenase,  terpenoid and the shikimate pathways. (Summary by Ana Valladares) Front. Plant Sci. 10.3389/fpls.2019.00781