High added-value compounds with antibacterial properties from Ginja Cherries by-products

Purpose: To test the antimicrobial properties of the extracts of stems and leaves of Ginja cherry plant. Both stems and leaves are waste in the production of the cherry liquor and they could be valorised by extracting valuable compounds, making the process more environmentally sustainable. Methods: The ethanol extracts from both stems and leaves were analysed by LC-ESI/MS to determine the phenolic composition. They were tested against Gram positive and Gram negative bacteria (Bacillus subtilis, Staphylococcus aureus MSSA, Staphylococcus aureus MRSA, Pseudomonas sp., Pseudomonas aeruginosa, Flavobacterium sp., Escherichia coli, Salmonella), using the disk diffusion technique and the broth dilution technique. Results: The extracts showed good antibacterial properties towards Gram positive and Gram negative bacteria. The values of the Minimum Inhibitory Concentration (MIC) were lower for Gram positive bacteria (10–15 mg/ml) than for Gram negative ones (10–100 mg/ml). The values of Minimum Bactericidal Concentration (MBC) were between 2 and 4 times higher than the MICs. Conclusions: The waste from Ginja cherry plants can be successfully employed to extract valuable compounds such as polyphenols, with antibacterial properties.info:eu-repo/semantics/publishedVersio

The potential of near and mid-infrared spectroscopy for rapid quantification of oleuropein, total phenolics, total flavonoids and antioxidant activity in olive tree (Olea europaea) leaves

Natural foods and food-related antioxidants such as phenolic phytochemicals are of great interest due to their preventive properties against oxidative damage. Olive tree leaves contain high quality and amount of phenolic compounds including oleuropein and therefore considered as nutraceutically valuable materials. The composition of olive leaves, its phenolics and antioxidant power are influenced by numerous factors causing great variation among samples. Additionally, traditional analytical methods performed to quantify these parameters in each product entail long and complicated sample preparation procedures, the use of toxic chemicals, skilled labors, instrumentation and sophisticated laboratory conditions. One appealing alternative is the use of infrared spectroscopy since it gives information about the food composition quickly and it is a multi-parametric and environmentally friendly choice. Therefore, we investigated the oleuropein, total phenolic content, total flavonoid content and antioxidant activity levels of 23 common cultivars of olive leaves harvested from Turkey and Italy using traditional reference methods and also developed near and mid-infrared based partial least squares regression (PLSR) models to predict these parameters without the need of sample preparation. Internal validations of the PLSR calibration models were done using full cross-validation and yielded very high correlation coefficients (0.95) and low errors in predictions (% standard error of cross-validation for parameters were lower than 7.54%). The levels of all the parameters of interest could be successfully predicted using both NIR and MIR instrumentation within seconds. Overall, infrared spectroscopy along with chemometrics exhibited great potential for future olive leave studies