## 1 Introduction  
Black tea is a fully fermented beverage with a high consumer preference, owing to its distinctive flavor profile and remarkable physiological health benefits [1]. In China, black tea can be classified into souchong, congou, and broken black tea, with congou representing the primary category for the largest production and sales volume [2]. The fundamental processing steps of congou black tea encompass withering, rolling, fermenting, and drying, which collectively contribute to the development of the appearance, infusion color, aroma, and taste [3, 4]. Drying is the final stage in black tea processing, serving to halt the fermentation by deactivating enzymes at high temperatures and to dehydrate the tea leaves. This process ensures the preservation and enhancement of the desirable qualities developed during fermentation [5, 6]. Different drying methods can yield variations in the black tea quality. [PERSON] et al. found that hot-air drying promoted the formation of sweet aroma substancesin black tea, while strip drying, drum drying, and pan-fired drying were beneficial for developing fruity aromas [7]. [PERSON] et al. demonstrated that, compared with the conventional hot-air drying, the black teas produced by microwave drying and halogen lamp-microwave drying showed superior color, taste, and aroma [8]. [PERSON] et al. investigated the effects of five different drying methods (hot-air drying, drum drying, sun drying, vacuum drying, and freeze-drying) on the sensory quality of black tea, indicating that hot air-dried black tea, rather than vacuum-dried black tea, exhibited a superior sensory quality [9]. [PERSON] et al. investigated the differences in the aroma of black tea under hot-air drying, sun drying, and pan-fired drying, showing that hot-air drying significantly enhanced the floral and roasted aroma of black tea [10]. The investigation by [PERSON] et al. also indicated that, compared to drum drying, hot-air drying exhibited a superior antioxidant capacity [11]. The drying time and temperature also affect the quality of black tea. The investigation by [PERSON] et al. discovered that the aroma profiles of black tea varied with the drying time, following a rise-fall trend with an increasing drying time, with drying at 85 \({}^{\circ}\)C for 45 min identified as a critical point influencing the aroma quality [12]. [PERSON] et al. demonstrated that increasing the drying temperature led to a gradual reduction in the levels of theaflavins, thearbigins, monosaccharides, and free amino acids, and a similar pattern was observed for the inhibitory effects on the \(\alpha\)-glucosidase and \(\alpha\)-amylase activity [13]. In China, different varieties of tea trees are used for congou black tea from different regions, but there is relatively little research on the processing technology of congou black tea with specific varieties. Lichuan black tea (LBT), a well-known congou black tea in China, is produced from the fresh leaves of local cultivar Echa No. 10, the primary cultivar in Lichuan City, Enshi Autonomous Prefecture, Hubei, China. The tea is manufactured through the steps of withering, rolling, fermenting, and drying to attain its distinctive characteristics: a wiry and even appearance, a fairly red and bright infusion color, a mellow and fresh taste, a strong and long-lasting aroma, as well as red and bright infused leaves. Previous studies on LBT were primarily focused on industrial development and brand establishment [14], paying little attention to its processing technology and quality chemistry [15; 16]. Currently, the research on its processing technology mainly revolves around variety optimization, withering methods, and fermentation degree. For example, [PERSON] et al. compared the quality differences in Lichuan black teas made from nine tea tree varieties and found Echa No. 10, Baiya Qilan, and Meizhan were suitable for processing Lichuan black tea [17]. [PERSON] et al.