Evaluation of antioxidant, anti-pathogenic and probiotic growth stimulatory activities of spent coffee ground polyphenol extracts

Antioxidant, anti-pathogenic and prebiotic activities of polyphenol extracts from spent coffee grounds (SCGE) (Coffea arabica) obtained after drip-brewing were investigated. Extraction experiments were done by a conventional solid-liquid method, using ethanol as a solvent at a different concentration ranges from 0 to 100%. Extraction of SCGE using 60% ethanol exhibited the highest total phenolic content of 146.78 mg gallic acid equivalents/g SCGE and antioxidant activity of IC50 2.83 mg/ml. The minimum inhibitory concentration of SCGE was demonstrated against Escherichia coli, Salmonella Typhimurium, Bacillus cereus and Staphylococcus aureus at 12.5 mg/ml. In comparison, SCGE did not express an inhibitory effect on the common probiotic bacteria, Lactobacillus spp. and Bifidobacteria spp. As such, spent coffee grounds can be recycled and used as a source of alternative natural functional food ingredients, while also providing sustainable management of an industrial by-product. (c) All Rights Reserved