Title:
Solvothermal Extraction of Phenolic Compounds and Antioxidants from Spent Coffee Grounds
Author(s):
Kapetanidis, A., Liakos, D., Vakalis, S.
Document(s):
Paper
Poster
Abstract:
Spent coffee grounds are generated worldwide as an underutilised residue that still contains recoverable phenolic and antioxidant compounds after brewing. This work compares three extraction routes for valorising spent coffee grounds: ultrasonic bath extraction, mechanical shaking and hydrothermal solvothermal treatment. Prepared samples containing 0.15 g of spent coffee grounds and 15 mL of methanol, ethanol or water were processed at 45 °C for 15, 30 and 45 min for the ultrasonic method and at 120 °C for 30, 60 and 120 min for hydrothermal extraction. Mechanical shaking was assessed for the same short extraction times under ambient laboratory conditions. Total phenolic content was determined by the Folin-Ciocalteu method and antioxidant activity by the DPPH radical scavenging assay. Ultrasonic extraction delivered rapid recovery, with phenolic contents up to 1250.6 mg kg-1 and antioxidant activity up to 31.96% RSA. Hydrothermal extraction produced the strongest intensification effect, reaching 6987 mg kg-1 with methanol and 7677.7 mg kg-1 with ethanol after 120 min, while methanol gave the highest antioxidant activity of 39.16% RSA.
Keywords:
antioxidant, biorefinery, resource recovery, spent coffee grounds, solvothermal extraction, analytical methods
Topic:
Biomass, Bio-based Products and Bioenergy Integration
Subtopic:
Integrated biorefineries for co-production of biofuels, biochemicals and bio-based products
Event:
34th European Biomass Conference and Exhibition
Session:
3CV.4.26
Pages:
494 - 499
ISBN:
978-88-89407-27-1
Paper DOI:
10.5071/34thEUBCE2026-3CV.4.26
Price:
FREE
