Metabolomics and flavor analysis reveal the main aroma characteristics contributors during the withering process of rose white tea

Ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) was used to detect the metabolites during the withering process of rose white tea to find out the differential metabolites, and headspace solid-phase microextraction–gas chromatography–mass spectroscopy (HS–SPME–GC–MS) was used to detect flavor compounds during the withering process of rose white tea and identify characteristic aroma compounds. By studying the flavor characteristics during the withering process, the reasons for the formation of the aroma of rose white tea can be revealed, providing a theoretical basis for the development of new tea products. There was a significant positive correlation (p<0.05) between total flavonoids and benzoids, organoheterocyclic compounds. The contents of compounds such as linalool, trans-cinnamic acid, L-phenylalanine, tyramine, indole-3-acrylic acid, and valine gradually rose during withering, yet declined subsequent to drying. The moisture content, total phenol content, and hydroxyl radical scavenging activity showed a negative correlation with the withering time. GC-MS results showed that 148 flavor compounds were identified in rose white tea, with linalool, citronellol, geraniol, phenylethanol, citral, phenylacetate, and methyl eugenol identified as the main contributors to the aroma characteristics of rose white tea. Citronellyl acetate and 2-undecanone were characteristic aroma compounds during the rose withering stages (WT0-WT48). The concentrations of citronellyl acetate exhibited an initial increase followed by a subsequent decline (WT0: 2.347mg/kg; WT12: 2.455mg/kg; WT24: 3.646mg/kg; WT36: 3.176mg/kg; WT48: 1.217mg/kg;). Phenylacetaldehyde and cyclotridecanone were unique aroma compounds found in dried rose white tea (HAD).