Milk tea is a globally popular new-style tea beverage product. In recent years, the industry has achieved rapid development in terms of scale expansion and quality iteration and upgrading. The flavor quality and product stability have become the focus of attention and research hotspots in this field. The chemical foundation of milk tea flavor, processing methods, and flavor quality evaluation approaches are thoroughly elaborated. The chemical basis of tea-based, milk-based, and milk tea flavors is systematically summarized, primarily including the analysis of key flavor compounds and the interactions between tea-based and milk-based substances. Subsequently, the tea-based production methods, mixed processing techniques, and factors influencing storage and preservation of milk tea are discussed. Furthermore, evaluation methods for milk tea flavor quality, including traditional sensory evaluation and intelligent assessment techniques are systematically outlined. This review not only summarizes the recent research progress but also looks forward to the interdisciplinary work that needs to be carried out in the future. These efforts aim to provide information on the transformation from the research stage of tea milk product formulas to the development of solutions with controllable quality. Thus, they offer valuable theoretical guidance for the formation and regulation of tea milk flavor and quality as well as the development of new products. This work aims to provide theoretical insights and technical support for the translation from laboratory formulations to quality-controlled industrial solutions.

The thick and mellow flavor of green tea serves as a core sensory indicator for assessing its quality grade and market value. This characteristic fundamentally represents the dynamic equilibrium of multiple flavor-contributing substances within the tea leaves, coupled with the synergistic effects of multi-sensory perception. Currently, the characteristics, chemical composition, and interactions underlying the thick and mellow flavor of green tea are the subject of intense research, yet no consensus has been reached within the academic community. This review systematically details the research progress on the chemical and quality characteristics and interactive effects of green tea’s thick flavor. First, the physiological basis for perceiving this thick and mellow flavor—the multisensory integration mechanism involving taste, smell, and oral tactile sensations—is explored. Second, evaluation methods for the thick and mellow flavor of green tea, including sensory analysis, instrumental analysis, and the integrated application of artificial intelligence technologies, are outlined. Third, the chemical basis of the thick and mellow flavor of green tea and the mechanisms of its interactions are systematically summarized. This review aims to systematically analyze the formation mechanisms and regulatory characteristics of the thick and mellow flavor of green tea, providing valuable reference for standardizing green tea flavor quality control.