Paper Title
Effect Of Methanol Concentration On Total Phenolic Content, Antioxidant Activity And Antibacterial Activity Of Spent Coffee Ground Extract

Total phenolic content, antioxidant and antibacterial activities of the extracts from spent coffee ground (SCGE) (Coffeaarabica) were investigated. First, the extraction experiments were carried out by the conventional solid–liquid method, using methanol as solvent at a different concentration range from 0 to 100%, and the influence of these operational variables on the content of total phenolic compounds and antioxidant activity of the produced extracts were evaluated. Extraction of SCGE using 60% methanol exhibited the highest total phenolic content of 158.20 mg gallic acid equivalents/g SCGE (Folin–Ciocalteau colorimetry assay) and antioxidant activity of IC50 3.41 mg/ml (DPPH assay). For the antibacterial activities investigated by disc diffusion and broth dilution assays, SCGE showed the inhibitory effects against the growth of both Gram-positive and Gram-negative pathogenic bacteria. The minimum inhibitory concentration (MIC) of SCGE was demonstrated against Escherichia coli, Salmonella typhimurium and Bacillus cereus. The lowest MIC was exhibited for SCGE extracted with 60% methanolshowing25 mg/ml. Hence, including the advantage for the sustainable management of the industrial by-product, spent coffee ground can be recycled and used as a source of alternative natural functional food ingredients. Index Terms- Antibacterial activity, Antioxidant, Coffee ground, Methanol