Beyond Composition: Processing-Driven Transformations and Functional Trade-Offs of Matcha Tea in Foods

Matcha tea, a powdered green tea produced from shade-grown Camellia sinensis leaves, has gained increasing attention as both a traditional beverage and a functional food ingredient. While previous reviews have focused on its phytochemical profile and biological activities, less attention has been given to the effects of food processing and matrix interactions on matcha bioactives. This review critically synthesizes current evidence on the processing-induced transformation, stability, and digestive bioaccessibility of key matcha compounds in real food systems. The production methods, phytochemical compositions, and reported health effects are summarized, with a particular emphasis on matrix-dependent changes during processing, including catechin degradation and epimerization, caffeine retention, L-theanine stability, and chlorophyll loss. The implications of these alterations for sensory quality, safety, and gastrointestinal release are discussed. Emerging findings on gut microbiota modulation and omics-based approaches are also highlighted. Collectively, the available evidence indicates that the functional value of matcha in foods is strongly influenced by processing–matrix interactions rather than native composition alone, leading to trade-offs among health functionality, consumer acceptance, and safety. By integrating food chemistry, processing, and nutritional perspectives, this review proposes a framework to guide the rational formulation of matcha-enriched foods and align health claims with realistic processing outcomes.