Analysis of Key Flavor Substances and Quality of Pomelo White Tea

The pomelo white tea obtained by the same tea billet and different scenting treatments was used as the experimental raw material, gas chromatography-mass spectrometry (GC-MS) combined with stoichiometry was used to analyze the differences in sensory quality, main flavor substances and volatile substances among the best, middle and worst samples (W2-1, W2-2, W2-3), tea blank (W2CK) and grapefruit (GF) of pomelo white tea, the aim was to explore the key flavor substances of pomelo white tea. The sensory results showed that the pomelo flower white tea W2-1 had obvious fragrance, fresh and thick, mellow taste and flower flavor. The corresponding process was scenting time of 14 h, flower amount of 80%, drying temperature of 70 ℃. The analysis of main flavor substances showed that the contents of tea polyphenols, caffeine and theanine in pomelo white tea and tea blank were significantly different (P<0.05), and the difference of water extract was small. The analysis of volatiles showed that a total of 233 volatile compounds were detected from the samples, mainly including terpenoids, esters and heterocyclic compounds. Among them, 64 substances had a relative content of more than 1%. The relative contents of linalool and dehydrolinalool were more than 100 μg/g, which were the main active substances of pomelo white tea. The analysis of aroma activity value showed that methyl benzoate, tetrahydro-4-methyl-2-(2-methyl-1-propenyl)-2H-pyran, β-ionone, linalool, 2,2,6-trimethyl-cyclohexanone, (E,E)-3,5-octadiene-2-one, dehydrolinalool and other substances were the aroma substances of grapefruit tea. The OAV values of these substances were more than 1000, which were mainly floral and fruity. The results of sensory evaluation, flavor substances and volatile substances were basically the same. This study is helpful to understand the aroma and taste quality chemistry of pomelo-flavored white tea, and provides a theoretical basis for improving the quality of pomelo-flavored white tea.