Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts

Abstract This study investigates the extraction of phenolic compounds and antioxidant activity from spent coffee ground (SCG) and coffee cherry pulp (CCP) using subcritical water extraction combined with high-pressure carbon dioxide (CO₂). The objective was to optimize extraction conditions to maxim...

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Main Authors: Varunnarin karprakhon, Rinlada Sirisangsawang, Kanidta Kaewkroek, Thammasak Rojviroon, Natacha Phetyim, Somboon Sukpancharoen
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-92401-1
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author Varunnarin karprakhon
Rinlada Sirisangsawang
Kanidta Kaewkroek
Thammasak Rojviroon
Natacha Phetyim
Somboon Sukpancharoen
author_facet Varunnarin karprakhon
Rinlada Sirisangsawang
Kanidta Kaewkroek
Thammasak Rojviroon
Natacha Phetyim
Somboon Sukpancharoen
author_sort Varunnarin karprakhon
collection DOAJ
description Abstract This study investigates the extraction of phenolic compounds and antioxidant activity from spent coffee ground (SCG) and coffee cherry pulp (CCP) using subcritical water extraction combined with high-pressure carbon dioxide (CO₂). The objective was to optimize extraction conditions to maximize total phenolic content (TPC) and DPPH radical scavenging activity. Using Design Expert V.13 and Central Composite Design (CCD), key parameters including extraction time (30–60 min), temperature (180–220 °C), and solid-to-water ratio (0.024–0.027 g/mL) were systematically analyzed. The optimal conditions for SCG were determined to be 198 °C, 0.027 g/mL solid-to-water ratio, and 60 min, yielding a TPC of 217.26 mg GAE/g DW and a DPPH value of 23.28 µMol TE/g DW. For CCP, the best extraction conditions were 189 °C, 0.024 g/mL solid-to-water ratio, and 54 min, resulting in a TPC of 230.13 mg GAE/g DW and a DPPH value of 32.63 µMol TE/g DW. The results indicate that CCP exhibited higher phenolic content and antioxidant activity than SCG, emphasizing its potential for valorization. Furthermore, Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Thin-Layer Chromatography (TLC) analyses confirmed the presence of bioactive compounds such as quinic acid, theobromine, and caffeine. These findings demonstrate the effectiveness of subcritical water and CO₂ extraction in enhancing the recovery of bioactive compounds from coffee byproducts. This optimized method provides a sustainable and solvent-free approach to extracting high-value phenolic compounds, with potential applications in functional food, nutraceutical, and pharmaceutical industries.
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spelling doaj-art-e29c120ad9774fc5aa7bd4cd7f33138e2025-08-20T03:01:23ZengNature PortfolioScientific Reports2045-23222025-03-0115111610.1038/s41598-025-92401-1Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproductsVarunnarin karprakhon0Rinlada Sirisangsawang1Kanidta Kaewkroek2Thammasak Rojviroon3Natacha Phetyim4Somboon Sukpancharoen5Department of Chemical and Materials Engineering, Faculty of Engineering, Rajamangala University of Technology ThanyaburiDepartment of Chemical and Materials Engineering, Faculty of Engineering, Rajamangala University of Technology ThanyaburiFaculty of Integrative Medicine, Rajamangala University of Technology ThanyaburiDepartment of Civil Engineering, Faculty of Engineering, Rajamangala University of Technology ThanyaburiDepartment of Chemical and Materials Engineering, Faculty of Engineering, Rajamangala University of Technology ThanyaburiDepartment of Agricultural Engineering, Faculty of Engineering, Khon Kaen UniversityAbstract This study investigates the extraction of phenolic compounds and antioxidant activity from spent coffee ground (SCG) and coffee cherry pulp (CCP) using subcritical water extraction combined with high-pressure carbon dioxide (CO₂). The objective was to optimize extraction conditions to maximize total phenolic content (TPC) and DPPH radical scavenging activity. Using Design Expert V.13 and Central Composite Design (CCD), key parameters including extraction time (30–60 min), temperature (180–220 °C), and solid-to-water ratio (0.024–0.027 g/mL) were systematically analyzed. The optimal conditions for SCG were determined to be 198 °C, 0.027 g/mL solid-to-water ratio, and 60 min, yielding a TPC of 217.26 mg GAE/g DW and a DPPH value of 23.28 µMol TE/g DW. For CCP, the best extraction conditions were 189 °C, 0.024 g/mL solid-to-water ratio, and 54 min, resulting in a TPC of 230.13 mg GAE/g DW and a DPPH value of 32.63 µMol TE/g DW. The results indicate that CCP exhibited higher phenolic content and antioxidant activity than SCG, emphasizing its potential for valorization. Furthermore, Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Thin-Layer Chromatography (TLC) analyses confirmed the presence of bioactive compounds such as quinic acid, theobromine, and caffeine. These findings demonstrate the effectiveness of subcritical water and CO₂ extraction in enhancing the recovery of bioactive compounds from coffee byproducts. This optimized method provides a sustainable and solvent-free approach to extracting high-value phenolic compounds, with potential applications in functional food, nutraceutical, and pharmaceutical industries.https://doi.org/10.1038/s41598-025-92401-1Spent coffee groundsCoffee cherry pulpSubcritical water-CO2 extractionPhenolic optimization
spellingShingle Varunnarin karprakhon
Rinlada Sirisangsawang
Kanidta Kaewkroek
Thammasak Rojviroon
Natacha Phetyim
Somboon Sukpancharoen
Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
Scientific Reports
Spent coffee grounds
Coffee cherry pulp
Subcritical water-CO2 extraction
Phenolic optimization
title Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
title_full Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
title_fullStr Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
title_full_unstemmed Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
title_short Optimization of combined subcritical water and CO2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
title_sort optimization of combined subcritical water and co2 extraction for enhanced phenolics and antioxidant activity from coffee byproducts
topic Spent coffee grounds
Coffee cherry pulp
Subcritical water-CO2 extraction
Phenolic optimization
url https://doi.org/10.1038/s41598-025-92401-1
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