Abstract: In order to investigate amino acids during the withering of white tea, metabolomics and proteomics were used to detect amino acids and related enzymes in the withered leaves at 0 h, 12 h and 30 h. The results show that the total amino acids had no significant change during withering process. While serine, leucine, phenylalanine, lysine, tyrosine, histidine, isoleucine, proline, valine, phenylalanine and γ-aminobutyric acid contents increased but N-acetyl-L-glutamic acid, reduced glutathione, N-α-acetyl-L-arginine decreased in the early stage of withering (0-12 h). The contents of glutamic acid and acetylglycine decreased in the later stage. Proteins tended to degrade during the withering process and the enzymes enriched in amino acid synthesis pathway were down-regulated in the early stage of withering, and the enzymes related to degradation were up-regulated in the later stage. The protein amino acids were mainly derived from protein hydrolysis, and then converted into non-protein amino acids. The γ-aminobutyric acid was regulated by glutamate decarboxylase under dehydration conditions. The increase of its content promoted the umami taste of white tea.

Key words: white tea, withering, metabolomics, proteomics, amino acid