Journal of Tea Science Research, 2024, Vol.14, No.5, 249-261 http://hortherbpublisher.com/index.php/jtsr 256 benzyl alcohol, and eugenol displayed significant fluctuations, indicating their potential roles in VOCs enhancement. Radar charts (B, C, D) for each tea type illustrated the changes in VOCs categories, including alcohols, aldehydes, ketones, esters, and others, over different time intervals (0, 12, 24, 48, and 168 hours). Green tea (B) showed a notable increase in alcohols and aldehydes initially, while oolong tea (C) exhibited balanced changes across all categories. Black tea (D) demonstrated substantial shifts in aldehydes and esters over time. This analysis underscored the influence of MeJA treatment on the aroma profiles of tea, contributing to enhanced flavor and potential health benefits. 6.3 Innovations in fermentation for specialty teas Innovations in fermentation techniques have led to the development of specialty teas with unique flavors and enhanced quality. For instance, the production of instant dark tea using submerged fermentation with Aspergillus niger as a starter has been optimized through the response surface methodology. This process resulted in a product with high theabrownins content, redness, and turbidity, and a sensory profile characterized by a mellow mouthfeel and mint aroma (Wang et al., 2018). Another innovative approach involved optimizing the fermentation process for dandelion black tea using the Box-Behnken response surface method. This method considered various fermentation conditions such as temperature, time, and humidity to enhance the functional components, activity, and sensory quality of the tea (Yaru et al., 2020). Additionally, determining the optimum fermentation time during black tea manufacturing is crucial for achieving the best quality. A study found that the highest theaflavins and thearubigins ratio, which was indicative of good quality, was achieved at a fermentation time of 50 minutes (Rahman et al., 2020). 7 Technological Advancements 7.1 Modern equipment and techniques in fermentation The advancement of modern equipment and techniques has significantly improved the fermentation process of tea, enhancing both its flavor and quality. For instance, the use of oxygen-enriched fermentation systems has been shown to improve the taste of black tea by reducing bitter and astringent metabolites. This method involved controlling oxygen concentrations during fermentation, which promoted the oxidation of catechins and other phenolic compounds, leading to a more desirable flavor profile (Chen et al., 2021). Additionally, the integration of high-throughput techniques such as 16S rRNA sequencing has allowed for a more detailed analysis of microbial community dynamics during fermentation, providing insights into how specific microorganisms influence tea quality (Liu et al., 2023). 7.2 Role of microbiome in tea fermentation The microbiome plays a crucial role in the fermentation of tea, affecting both its chemical composition and sensory characteristics. Studies have shown that the microbial community in natural solid-state fermentation (SSF) is essential for the formation of unique flavors in Pu-erh tea. For example, Aspergillus is identified as a key flavor-producing microorganism in the early stages of SSF, while other genera such as Bacillus and Debaryomyces contribute to flavor production in the later stages (Li et al., 2018). Integrated meta-omics approaches have further advanced our understanding of the microbiome's role in tea fermentation, revealing the complex interactions between microbiota, metabolites, and enzymes that contribute to the quality of Pu-erh tea (Zhao et al., 2019). Moreover, the modulation effects of microorganisms on tea during fermentation have been extensively reviewed, highlighting their impact on polyphenol composition, biological activities, and sensory characteristics (Hu et al., 2022). 7.3 Automation and control in fermentation processes Automation and control technologies have revolutionized the fermentation processes, ensuring consistent quality and efficiency. The use of synthetic microbiota and environmental control factors can regulate spontaneous food fermentations, making them more predictable and controllable. For instance, in the fermentation of Chinese liquor, core microbiota associated with flavor compounds formation can be identified and used to construct synthetic microbiota, which can then be regulated through environmental factors to optimize flavor production (Wu et al.,
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