Objective  Effect of rocking-withering in processing Wuyi rougui tea on the metabolites in leaves was analyzed using GC-TOF-MS non-targeted metabonomics.

  Method  Freshly plucked buds and leaves from Wuyi rougui tea bushes were processed according to the conventional northern Fujian technique with or without (CK) the rocking-withering procedure. The non-targeted metabolic analysis was performed to obtain data for differentiating the metabolites in the leaves by multivariate and univariate statistical analyses. A KEGG pathway enrichment analysis was conducted to identify the associated metabolic pathways.

  Result  Compared with the conventional brief withering under the sun, the different metabolites of tea leaves without rocking (CK) and after rocking-withering were 21 and 14; meanwhile tea leaves after rocking-withering had 9 significantly upregulated and 3 downregulated metabolites compared to leaves without rocking (CK) . The most significant differentiations were found in the metabolites such as shikimic acid, citric acid, L-malic acid, raffinose, and maltose.

  Conclusion   Rocking-withering stimulated the tea leaves to produce certain intermediate products in the tricarboxylic acid cycle and caused a reduction on shikimic acid. It was the metabolisms of amino acids and carbohydrates that were largely affected. The significantly reduced shikimic acid and increased phenylalanine in LY7M metabolite might play a role in the synthesis of aromatic compounds that give the oolong tea its characteristic sensory quality.