Applications of Electronic Nose Technology in Tea Processing: A Comprehensive Review

Tea quality is fundamentally determined by the complex biochemical transformations occurring during manufacturing. Traditional sensory evaluation, while essential, suffers from inherent subjectivity and cannot meet the demands of modern, industrial-scale production monitoring. This review critically examines the application of electronic nose (E-nose) technology throughout the tea-processing pipeline, covering multiple transducer technologies including metal oxide semiconductor (MOS) sensors, quartz crystal microbalance (QCM) sensors, conducting polymer (CP) sensors, and emerging chemiresistive platforms. Particular emphasis is placed on the E-nose’s capacity for real-time, non-destructive monitoring of key processing stages, including withering, rolling, fermentation, and drying. We analyze how optimized sensor arrays capture dynamic volatile organic compound (VOC) evolution, enabling the precise identification of optimal processing endpoints, especially in black tea fermentation control. Furthermore, this review evaluates how advanced pattern recognition algorithms (such as deep learning models) and multi-sensor data fusion strategies enhance the robustness and accuracy of process monitoring. By correlating E-nose response patterns with critical biochemical markers and traditional taster metrics, this paper demonstrates the technology’s pivotal role in transitioning tea manufacturing from experience-based craftsmanship to data-driven automation, ultimately ensuring superior product consistency and efficiency.