High-pressure processing-assisted in-situ extraction of caffeine, chlorogenic acid, phenolic content, and antioxidant properties of green coffee bean

This research aimed to efficiently extract valuable bioactive compounds from green coffee beans (GCBs), meeting the rising demand for natural compounds in the pharmaceutical and food industries. The study sought to overcome the limitations of conventional extraction techniques, such as low efficiency, prolonged processing, and heat-sensitive compound degradation, by employing an eco-friendly solvent and high-pressure assisted extraction. Experiments were conducted at different pressure levels (300, 400, and 500 MPa), treatment times (10, 20, and 30 min), and using water, ethanol, and their combination (1:1) as solvents. The study evaluated the impact of these variables on radical scavenging activity (RSA), caffeine content, chlorogenic acid (CGA) levels, total phenolic content (TPC), pH, cyclic voltammetry, and scanning electron microscopy (SEM) analysis. Results were compared with conventional extraction and untreated extracts. High-pressure processing (HPP) significantly enhanced RSA, reaching a maximum of 94.872 +/- 0.290%, except for ethanol extracts. CGA content decreased with increasing pressure, correlating with improved antioxidant activity. Caffeine content remained higher even at shorter treatment times (1.170 +/- 0.131 mg/mL). The ethanolic extract at the lowest pressure and time yielded the highest TPC (74.130 +/- 1.141 mg of GAE/mL). Importantly, pH showed no significant variations. SEM analysis revealed a denser microstructure in the residual green coffee powder. Voltammetric tests confirm potent antioxidant properties due to its polyphenolics oxidizing within the potential range. This study demonstrates HPP as an eco-friendly method for extracting bioactive compounds from GCBs. It effectively addresses the limitations of conventional extraction techniques, offering a sustainable and efficient alternative.Practical applicationsHigh-pressure-assisted extraction is a novel method of extracting bioactives from natural products. The current study proposes the innovative approach to optimize the processing parameters for extracting the bioactives (total phenols, CGA, and caffeine) from the GCB under HPP with improved antioxidant properties. This greener approach of high-pressure-assisted extraction is an alternative method to conventional extraction. This can be achieved with limited time of extraction using water or ethanol:water as a prospective alternative solvent devoid of harmful chemicals to extract with higher natural antioxidant capacity. Also, extensive research on green coffee extracts has demonstrated that extracted bioactives find applications as functional ingredients, natural preservatives, and potential natural antioxidants in the pharmaceutical and food industries. This graphical abstract provides an overview of the high-pressure processing-assisted extraction capability of bioactive compounds including caffeine, chlorogenic acid, phenolic content, and potent antioxidant properties from green coffee beans. It also includes insights into the structural changes and cyclic voltammetry analysis of the green coffee extract. image