Physicochemical and phytochemical characterization of green coffee, cinnamon clove, and nutmeg EEGO, and aroma evaluation of the raw powders

The aim of the present study was to estimate the antioxidant activity, total phenolic, caffeic acid and quercetin contents, along with color parameters and pH of green coffee, cinnamon clove and nutmeg powders using their ethanolic extracts of grape origin (EEGO). In addition, volatile compounds’ analysis was done using solid phase dynamic extraction coupled to gas chromatography mass spectrometry (SPDE/GC–MS) to the raw powders. Results showed that the highest average antioxidant activity (59.62%), total phenolic content (1160.49 mg GAE/L), and caffeic acid content (1978.20 mg/L) had green coffee EEGO. The respective values for cinnamon clove EEGO were: 55.12%, 1120.24 mg GAE/L, and 634.66 mg/L, whereas those of nutmeg EEGO were: 57.24%,199.39 mg GAE/L, and 30.43 mg/L. Quercetin had the highest content in cinnamon clove (566.77 mg/L), followed by green coffee (141.75 mg/L), and nutmeg 18.24 (mg/L) EEGO, respectively. Color parameters and pH differed significantly ( p < 0.05 ) among the studied EEGO. Volatile compounds (alcohols, aldehydes, esters, ketones, phenolic compounds, etc.) differed significantly ( p < 0.05 ) among the studied powders. The present findings confirm that ethanol of grape origin can be used as an edible and eco-friendly solvent to extract the phytochemicals found in green coffee, cinnamon clove, and nutmeg powders (which also possess a characteristic aroma), providing additional knowledge, on the potential use of these extracts as natural food preservatives. Ongoing research will further approve this hypothesis.