The Valorization of Coffee By-Products and Waste Through the Use of Green Extraction Techniques: A Bibliometric Analysis

Coffee is one of the most widely consumed beverages worldwide. This has motivated the coffee industry to adopt sustainable practices, with an increased emphasis on environmentally friendly extraction methods. The objective of this study was to explore, through a bibliometric analysis, the identification of influential researchers, institutions, emerging topics, and gaps concerning the valorization of coffee by-products and residues using green extraction techniques. A total of 7306 scientific publications on green extraction were identified, 72 specifically addressing coffee or its by-products. The analysis highlights a focus on innovative green technologies, such as natural deep eutectic solvents, ultrasound-assisted or microwave-assisted extraction. These methods enable the efficient and sustainable extraction of bioactive compounds, including polyphenols, chlorogenic acid, caffeine, with potential applications in food, pharmaceutical, and energy industries. Despite this, research on coffee by-products remains limited, partly due to their use in other applications, such as biochar, animal feed, and construction materials, which do not rely heavily on green technologies. Key contributors to the field include countries such as Spain, Italy, Brazil, and China. This study emphasizes the potential of coffee waste to generate high-value products through sustainable methodologies, identifies noteworthy research and key actors in the field, and underscores the necessity for further innovation and collaboration.