Utilizing nontargeted metabolomics integrated with quality component quantitation via differential analysis to reveal the taste differences between and metabolite characteristics of hawk black tea and hawk white tea.

This study conducted a comprehensive analysis of the differences in the taste characteristics of hawk black tea and hawk white tea, exploring the intrinsic relationship between nonvolatile metabolites and these taste characteristics. The results revealed significant differences in taste properties of the two types of hawk tea. Hawk black tea mainly exhibits a fresh, sweet, and sweet aftertaste quality, whereas hawk white tea offers a mellow and pure taste. Comparative analysis revealed that the content of amino acids and carbohydrates in hawk black tea was significantly higher than that in hawk white tea, while the content of flavonoids and organic acids was relatively lower. Quality composition results indicated significant differences in the 13 major quality components and water extracts between the two hawk teas, aligning with the quantitative descriptive analysis results. Additionally, through weighted gene coexpression network analysis, significant associations were found between 671 metabolites across 155 metabolic pathways and 9 taste characteristics. Among them, flavonoid biosynthesis and degradation are the main metabolic pathways of the two types of hawk tea. And it was found that butin, phlorizin, naringin, dihydrokaempferol, sakuranetin, apigenin, (-)-epicatechin, (+)-gallocatechin, caffeoyl shikimic acid, homoeriodictyol, which are 10 flavonoids, are the key metabolites affecting the taste difference of hawk black and white tea. Additionally, this study found that hawk tea does not contain caffeine, which is of great significance for the development of caffeine-free beverages in the future.