Synergistic Approach to Green Coffee Bean Bioactive Extraction: Integrating Cold Plasma Bubbling and In Situ High-Pressure Processing

This study investigated the combined effect of plasma bubbling and high-pressure processing (HPP) on the extraction of bioactive compounds from green coffee beans (GCBs). Plasma bubbling pretreatment was conducted for 10 min, followed by HPP with different factors: pressure (300, 400, and 500 MPa), extraction time (10 and 20 min), and solvent (water, ethanol, and water–ethanol mixture). The extracted green coffee samples were analyzed for pH, chlorogenic acid (CGA) content, caffeine content, total phenols, and radical scavenging activity. Among the solvents tested, water exhibited the highest efficiency in extracting caffeine from green coffee extract (GCE), while an ethanol–water mixture yielded the highest CGA content. Ethanol proved to be more effective in extracting total phenols. The antioxidant activity of water and ethanol–water extracts was stronger than that of ethanol extracts. The pH of the extracts varied depending on the solvent and treatment conditions. The combination of plasma bubbling and HPP provides a promising method for extracting bioactive compounds from GCBs. The results indicate that water and ethanol–water mixtures are suitable solvents for extracting caffeine, CGA, and total phenols. The stronger antioxidant activity observed in water and ethanol–water extracts suggests their potential application in the food and pharmaceutical industries. These findings contribute to developing efficient extraction techniques for bioactive compounds, offering new opportunities for green coffee utilization.