Black tea (Fuyun 6) samples collected from three regions, Youxi, Fu’an, and Datian, were analysed by automatic thermal desorption-gas chromatography–mass spectrometry (ATD-GC–MS) combined with the electronic nose (E-nose) technique to investigate the aroma composition differences between black teas from different regions. The response surface methodology was used to optimize the ATD conditions for extracting the aroma components from the black tea. The results revealed that the optimal conditions for aroma component accumulation from black tea samples included a sample weight of 2.8 g, an adsorption time of 39 min, an adsorption temperature of 75 °C, and a cold trap temperature of −30 °C. The ATD-GC–MS analyses identified a total of 71 aroma components in the black tea samples, of which 31 were utilized to differentiate the origins of the black teas. Additional aroma activity analyses indicated that benzyl alcohol, linalool, hexanal, octanal, and nonanal had odour activity values (OAVs) greater than 10. Additionally, the OAV of decanal exceeded 100, indicating its significant contribution to the aroma profile of Fuyun 6 black tea. The E-nose results demonstrated the ability to differentiate the black tea samples from the three different origins. This study successfully identified the specific aroma substances associated with different tea origins, providing valuable insights into the aroma characteristics of black teas from various regions.

This study investigated the potential mechanism of action of tea polyphenols (TPs), one of the major active ingredients in tea, to enhance heat resistance in Drosophila and the attenuating effect of heat treatment of TPs on their efficacy. The results showed that TPs were able to prolong the average survival time of Drosophila under high-temperature stress (p < 0.05), but the effect of TPs in prolonging the survival time of Drosophila melanogaster was significantly reduced (p < 0.05) with increasing TP heat-treatment time until it disappeared. The composition of TPs changed after heat treatment. It was also shown that the weakening of the effect of TPs in improving the heat tolerance of Drosophila was related to the decrease in the content of catechins and phenolic acids in their fractions as well as with the increase in the content of laccase. Transcriptomic analysis showed that the effect of TPs on heat tolerance in Drosophila melanogaster was closely related to the longevity regulation pathway, the neuroactive ligand–receptor interaction signaling pathway, and the drug metabolism–cytochrome P450 pathway. Metabolomics analysis showed that the effect of TP intervention in improving the body’s heat tolerance was mainly related to amino acid metabolism and energy metabolism. However, thermal processing weakened the relevance of these transcriptomes and metabolomes. The present study reveals the mechanism of action by which heat-treated TPs affect the body’s heat tolerance, which is important for the development and utilization of the heat-protection function of tea.

White tea (WT) and Indocalamus latifolius leaves (ILLs) are valued for their distinctive aromas and bioactive properties. In this study, flavonoid extraction from ILLs was optimized using total flavonoid yield as the response variable through single-factor experiments and response surface methodology. The resulting Indocalamus latifolius leaf extract (ILLE) was vacuum-concentrated and sprayed onto WT to produce Indocalamus latifolius leaf–white tea (IT). The effects of spray ratio, spraying liquid temperature, and drying temperature on the sensory and chemical qualities of IT were further evaluated. Untargeted metabolomics was performed to compare the metabolite profiles of IT and WT. The optimal extraction conditions for ILLs’ flavonoids were 95 °C, 120 min, and a liquid-to-solid ratio of 60:1 mL/g, yielding 4.39 mg/g total flavonoids. The optimal processing parameters for IT were a spray ratio of 1:1.75 g/g, a spraying liquid temperature of 50 °C, and a drying temperature of 105 °C. Compared with WT, IT showed improved sensory and biochemical qualities, including a richer and more persistent ILLs aroma, a more refreshing and more layered taste, and significantly higher levels of water extracts, flavonoids, tea polyphenols, soluble sugars, and amino acids (p < 0.05). Metabolomic analysis revealed clear compositional differentiation between IT and WT, including the enrichment of several metabolites, some with potential functional relevance, as well as aroma-active compounds. These findings provide chemical and sensory evidence for the distinctive quality of IT and support further development of this novel specialty tea.