Correlation Analysis and Spiking Validation of Flavor Compounds Modulating Bitterness and Astringency in Jasmine Tea

To elucidate the chemical basis underlying bitterness and astringency modulation in jasmine tea, four green tea bases and their corresponding jasmine teas were analyzed using weighted gene co-expression network analysis (WGCNA) combined with spiking validation experiments. WGCNA revealed that catechin, gallocatechin gallate, aspartic acid (Asp), glutamic acid (Glu), arginine (Arg), and alanine (Ala) were positively associated with sweetness and umami but negatively associated with bitterness and astringency. Spiking experiments showed that taste modulation was both concentration- and matrix-dependent. Glu and Asp effectively reduced bitterness at suitable concentrations, whereas the effects of theanine and Arg varied among tea matrices. Bitterness and astringency of jasmine tea infusion are modulated by the combined effects of the chemical matrix of tea base, providing a theoretical basis for tea-base selection and jasmine tea flavor optimization.