Green Tea: Bioactive Compounds, Phytochemical Profile and theirApplications in Value-added Functional Food Products - A SystematicReview

Introduction: Green tea, a minimally processed Camellia sinensis product, retains abundant polyphenols and catechins; this review synthesizes evidence on its bioactives and their applications in value-added functional food development. Methods: A systematic search of Web of Science, Scopus, PubMed, and Google Scholar identified 78 studies, of which 21 met the inclusion criteria and focused on randomized controlled trials. The review followed PRISMA guidelines, with protocol alignment to PROSPERO. Two independent reviewers screened studies, extracted data using a standardized form, validated findings, and fully documented the process to ensure transparency, accuracy, and methodological credibility. Results: Green tea bioactives, particularly epigallocatechin gallate (EGCG), demonstrated significant antioxidant, anti-inflammatory, cardioprotective, antimicrobial, and anticancer activities across preclinical and clinical evidence. However, translational application in functional foods and nutraceuticals remains constrained by physicochemical instability, poor bioavailability, sensory limitations (notably bitterness), safety considerations, and regulatory challenges Discussion: Green tea is rich in polyphenols, notably EGCG, plus L-theanine, caffeine, and organic acids, conferring antioxidant, anti-inflammatory, antimicrobial, cardioprotective, and anticancer effects relevant to functional foods. Wider application is limited by catechin instability, poor bioavailability, bitterness, safety, and regulation. Current research targets improved processing, encapsulation-based delivery systems, and synergistic bioactive formulations to enhance stability, efficacy, sensory acceptance, and translational potential. Conclusion: Green tea offers strong functional food potential due to its antioxidant-driven anti-cancer, anti-inflammatory, and neuroprotective effects, but challenges like low bioavailability and inconsistent trial results persist. Evidence suggests benefits for chronic disease and weight management, yet large, well-controlled trials—especially in non-Asian populations— are still needed.