Evaluation of the antioxidant and antimicrobial activities of the spent coffee extracts and their applications as natural food preservatives of chicken fillets

Document Type : Original Article


Regional Center for Food and Feed, Agricultural Research Center, Giza, Egypt


The present study aimed at evaluating the phytochemical composition, antioxidant, and antimicrobial potentials of spent coffee extracts (SCE) to use these extracts as natural preservatives of food. The effectiveness of SCE in postponing the oxidation and extending the shelf life of chicken fillets through delaying the microbial growth were investigated. Spent coffee was collected and extracted using water and ethanol. The extracts were analyzed for their bioactive components using Gas chromatography-mass spectrometry (GC/MS) and antioxidant properties using different spectrophotometric assays. The detected bioactive components were mainly fatty acids (80 %), flavonoids, terpenoids and caffeine (5.4 %). Spent coffee ethanolic extract was richer in its active components than the aqueous one. Additionally, the in vitro antibacterial efficacy of the extracts against several food-borne bacterial strains revealed that spent coffee ethanolic extract was effective against all the tested bacteria with inhibitory percentages ranging from 34.62 to 66.69 %, whereas the aqueous extract expressed an inhibitory effect only against Salmonella typhimurium  (35.82 %). To assess the practical utility of SCE as food preservatives, chicken fillets were treated with SCE at two levels (0.1 % and 0.2 %) and butylated hydroxytoluene (BHT, 0.02 %) was used as a synthetic preservative. The antioxidant and microbiological attributes of the SCE treated chicken fillets were investigated at 3 d intervals for 15 d.  The results showed that inclusion of SCE enhanced the chicken fillets antioxidant properties and microbiological characteristics. Furthermore, the chicken fillets treatments succeeded in stopping the rise of the total bacterial count, with no Salmonella sp. or fungal contamination, and additionally, the overall total coliform was less than 102 cfu/ g; indicating their safety for human consumption. In conclusion, this study proved that spent coffee-treated chicken fillets exhibited extended shelf life through delaying the microbial spoilage and maintaining the antioxidant quality.