Bingdao ancient tree tea (BATT), a type of raw Pu-erh tea, is renowned for its brewing durability, characterized by a unique aroma and flavor. To explore the dynamic changes in infusion quality and the impact of multiple steeping process, BATT was brewed 14 times, and its sensory attributes, infusion color, and chemical composition were assessed across different brewing intervals. The color of the tea infusion remained relatively stable throughout the brewing process. Sensory evaluation indicated that BATT exhibited optimal sensory quality between the third and seventh infusions. While the leaching of polyphenols showed minimal variation across brews, the concentrations of ester-catechins, non-ester catechins, free amino acids, and caffeine after the seventh brewing decreased by 28.82%, 21.83%, 28.86%, and 40.37%, respectively. Our results indicated that higher concentrations of flavor compounds in the BATT infusion appeared between the fourth and seventh brews. This study provides a theoretical basis for understanding the brewing characteristics of BATT.

Gardenia black tea (GBT) is a prized Chinese scented tea, renowned for its pleasant aroma. However, the influence of repeated scenting rounds on its volatile profile remains poorly characterized. This study investigated the aroma profiles of GBT produced with zero, two, and three scenting rounds (T0, T1, T2) using sensory evaluation and Headspace Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS). Sensory analysis revealed that GBTs (T1, T2) scored significantly higher in aroma and taste than the black tea base (T0). GC-MS analysis identified numerous volatile compounds, with esters, terpenoids, and ketones being predominant. Multivariate analysis identified 52 key volatiles (VIP > 2.0) that differentiated the tea samples. Among these, 28 compounds had odor activity values (OAVs) > 1, indicating significant sensory contributions. Ultimately, 11 volatiles, including (Z)-hex-3-enyl acetate, linalool, and (E)-hex-2-enal, were identified as the crucial basis for the characteristic fresh and floral scent of GBTs. The specific abundance levels of these compounds are hypothesized to underlie the superior, fresh, and elegant aroma of T1, compared to the slightly ripe and stuffy floral notes of T2. Therefore, it is advisable to prioritize two rounds of scenting during the production of gardenia black tea. These findings provide a theoretical foundation for optimizing the scenting process and enhancing the quality of GBT.

Spreading is the key process for ensuring green tea quality. However, the effect of blue light intensity conditions on the formation of green tea aroma and the evolution of key volatile compounds has not been assessed to date. Four tea samples treated with different light conditions (blue light intensities) were used to investigate the effect of spreading treatment on changes in the composition and content of volatile compounds. Volatile compounds in green tea samples were detected using headspace-solid phase microextraction and gas chromatography-mass spectrometry under different light conditions. Orthogonal partial least squares discriminant analysis (OPLS-DA) and relative odor activity value (rOAV) analyses were then applied to clarify the best blue light condition for forming aroma and associated compounds. The 116 volatile compounds were detected in the green tea samples, of which alcohols were the most abundant. The findings demonstrated that MBL (middle-intensity blue light; 150 μmol/(m²∙s)) treatment was the most effective condition for developing an intense and persistent fruity and floral scent compared to HBL (high-intensity blue light; 300 μmol/(m²∙s)) and LBL (low-intensity blue light; 75 μmol/(m²∙s)). This study underscores how blue light intensity conditions shape green tea aromas and offers operational insights. It also provides a theoretical basis for controlling light conditions in the process of green tea spreading

Anthracnose is a leaf fungal disease caused by multiple Colletotrichum species. Currently, the predominant deployment of chemical agents for anthracnose control increases ecological pollution risks and potential food safety concerns. The comprehension of the pathogenic mechanism and physicochemical properties of anthracnose is, therefore, essential for effective prevention and control. In this study, the pathogenic strain (pathogen) was isolated from the infected tea plant (Camellia sinensis) leaves and was identified as Colletotrichum gloeosporioides based on microscope observations and gene sequences. This fungus exhibited optimal growth at 28 °C and a pH of 6, with a lethal temperature threshold of 53 °C on PDA plate medium. The 80% tea saponin and 10% polymycin B could effectively inhibit its mycelium growth. Notably, the 10% polyoxin B exhibits a stronger inhibitory effect with an EC₅₀ value of 1.07 mg mL⁻¹. Following infection with Colletotrichum gloeosporioides, the resistant cultivar ‘Zhongcha 108’ exhibited higher levels of H₂O₂ and O₂⁻ than the susceptible ‘Longjing 43’, with later symptom onset and slower disease progression. Although the exogenous treatment of methyl jasmonate (MeJA) did not inhibit C. gloeosporioides directly, it significantly reduced lesion areas in ‘Longjing 43’ leaves caused by C. gloeosporioides. This treatment increased peroxidase and superoxide dismutase activities, but limited malondialdehyde content, thereby enhancing ‘Longjing 43’ resistance to the pathogen. The findings provide scientific guidance for the anthracnose prevention and control in tea gardens.

Tea plants (Camellia sinensis) uniquely hyperaccumulate fluoride (F) and concurrently exhibit a preference for ammonium nitrogen (NH₄⁺-N) over nitrate nitrogen (NO₃⁻-N). However, the mechanistic basis for co-existence of NH₄⁺-N preference and F hyperaccumulation in C. sinensis remains unexplored. Here, we investigated F accumulation and translocation with varying N supplies (0 mM and 2.854 mM N with NH₄⁺-N:NO₃⁻-N ratios of 3:1, 4:0 and 0:4) and F concentrations (0, 8 and 16 mg·L⁻¹ NaF) to reveal the mechanism driving NH₄⁺-N preference and F hyperaccumulation in C. sinensis. Results show that NH₄⁺-N supply enhanced H⁺ efflux, mobilizing aluminum (Al) to form mobile Al-F complexes for translocation to shoots, thereby alleviating F toxicity in roots. This process was facilitated by transporters including CsCLCd, CsCLCe, CsCLCf2 and CsFEX. In contrast, NO₃⁻-N promoted root sequestration of F as immobile calcium (Ca)-F complexes, exacerbating damage. Under NO₃⁻-N supply, CsCLCb primarily mediated NO₃⁻ transport, while CsCLCc, CsCLCe, CsCLCf1, CsCLCf2 and CsFEX were involved in F transport. In leaves, CsCLCd, CsCLCe, CsCLCf1, CsCLCf2, CsCLCg and CsFEX mediated vacuolar sequestration under both N conditions. These findings elucidate that NH₄⁺-N preference is mechanistically linked to F hyperaccumulation through an Al-assisted translocation pathway, which confers tolerance by exporting F from roots.

The warm and smooth taste, combined with the pleasant sweet aroma, are unique quality characteristics of Pingyang Huangtang (PYHT) tea. However, the potential to refine the quality through agricultural practices remains poorly explored. In this study, a one-year field experiment was conducted in the core production region of PYHT tea to assess the impacts of organic fertilizer substitution on tea quality. The experiment consisted of three fertilization regimes: T0 (pure chemical fertilizer), T1 (chemical fertilizer with rapeseed cake), and T2 (chemical fertilizer with newly organic fertilizer). Through sensory evaluation, determination of major biochemical components, and GC-MS analysis of aromatic compounds, combined with multivariate statistical methods, results showed that varied fertilization treatments significantly affected the aroma quality of PYHT tea, as indicated by T2 scoring the highest, surpassing the T0 and T1 scores, whereas no significant differences were observed in appearance, taste, liquor color, infused tea, or total score. Compared with chemical fertilization, organic fertilizer substitutes significantly reduced the total content of ammonia acids, a change primarily attributed to the decrease in the Thea, Arg, and Val levels, while the tea polyphenols and caffeine had no significant differences among treatments. GC-MS and multivariate analysis identified five key volatiles as octan-1-ol, linalool, geraniol, benzeneacetaldehyde, and δ-cadinene that differentiated the tea samples’ aroma profile. The distinct abundance patterns of these compounds are likely responsible for a fresher and more pronounced floral style of T2 tea, compared to the slightly less fresh floral notes of T0 tea and the stuffy floral expression of T1 tea. In summary, the research findings offer actionable guidelines for fertilizer application to PYHT tea production, improving aroma quality and increasing its overall market value.