Work

Valorization of Spent Coffee Grounds as a Functional Protein Ingredient for Sustainable Aquafeed Production

Year: 2026

Type: article

Abstract: Spent coffee grounds (SCGs) represent a globally abundant agro-industrial byproduct with underexploited potential in circular bioeconomy applications. This study investigates the extraction, characterization and functional integration of SCG protein concentrate into aquafeed formulations for common carp (Cyprinus carpio). Protein was recovered through alkaline extraction followed by isoelectric precipitation, yielding a concentrate incorporated at 5% into a mixed plant and fishmeal diet produced by cold pelletizing. Compositional analysis performed by FT-NIR showed 33.6% crude protein, 7.24% lipids and 7.85% fiber, while ICP-OES confirmed substantial levels of essential minerals including Ca, P, K and Mg (15.3, 8.4, 10.4 and 2.3 g/kg). SCGs contributed bioactive compounds, with total polyphenols reaching 1.521 ± 0.065 mg GAE/g DM and an antioxidant capacity of 3.35 ± 0.03 mg TE/g DM. Pellets exhibited high water stability (91.8% retention after 30 min), and a short-term feeding test demonstrated strong acceptance by juvenile carp (91.2 ± 2.1%) consumption. Residual caffeine levels remained low (3.5 mg per g dry weight) and within safe exposure margins for freshwater fish. The results demonstrate the technical feasibility of incorporating SCG protein concentrate into compound aquafeeds without compromising pellet integrity or short-term palatability, while increasing feed-level antioxidant potential. However, the findings represent a proof-of-concept evaluation. Further research involving longer-term feeding trials, digestibility assessment, and amino acid profiling of complete diets is required to validate nutritional performance and optimize inclusion strategies for sustainable aquaculture.

Source: Applied Sciences

DOI: 10.3390/app16041914

Authors: Anca Becze, Dorina Simedru, Lucian Dordai, Adrian Vasile Timar, Paul Uiuiu

Institutions: Research Institute for Analytical Instrumentation, National Institute of Research and Development for Optoelectronics, University of Oradea, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca

Language: English

Topic: Aquaculture Nutrition and Growth

Subfield: Aquatic Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Responsible consumption and production, Zero hunger, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $2,896