Inhibition of the Decrease of Linalool in Muscat Wine by Phenolic Acids

Two white wine extracts rich in phenolic acids, caffeic acid and gallic acid were tested as inhibitors of the decrease of linalool in Muscat wine. Each wine extract was added at 60 ppm and each phenolic acid at 40 ppm. Immediately after the addition of each wine extract or phenolic acid, no effect on the concentration of linalool was observed, but it decreased from the initial 470.9 to 223.3 μg/L after storage in open bottles at 20 °C for 4 days. Its decrease was significantly inhibited by each wine extract or phenolic acid

Scavenging Capacities of Some Wines and Wine Phenolic Extracts

The aim of this study was to assess the ability of different wines – a sweet red, a dry red, a sweet white, and a dry white – to scavenge the stable 1,1’-diphenyl-2-picryl-hydrazyl radical (DPPH.) and to determine their phenolic composition. Both red wines contained, apart from anthocyanins, also higher concentration of total phenolics, tartaric esters, and flavonols than the two white wines. All wines exhibited scavenging activity analogous to their total phenolic content. However, their phenolics differed in antiradical potency, which was visible in their EC50 values. The dry red wine, Xinomavro, had a lower EC50 value, indicating the higher antiradical potency of its phenolics. The scavenging capacities of phenolic extracts from Xinomavro red wine on hydroxyl radicals, superoxide radicals, and singlet oxygen were also assessed. Wine total extract was fractionated by extraction, and each of the three fractions was then subfractionated by column chromatography into two subfractions. Wine total extract, and its fractions and subfractions exhibited scavenging capacity on hydroxyl radicals, superoxide radicals, and singlet oxygen, indicating the activity of many wine phenolics. The most active wine extracts towards hydroxyl radicals were characterized by the high peaks of flavanols, anthocyanins and flavonols in their HPLC-DAD chromatograms. The most active extract towards superoxide radicals was rich in flavanols and anthocyanins. The characteristic phenolics of the most active wine extracts towards singlet oxygen were flavanols, flavonols and phenolic acids. The ability of all red wine phenolic extracts to scavenge singlet oxygen, along with hydroxyl and superoxide radicals, emphasizes its health functionality

Potential Antimicrobial Activity of Red and White Wine Phenolic Extracts against Strains of Staphylococcus aureus, Escherichia coli and Candida albicans

The aim of this study was to assess antimicrobial activities of wine phenolic extracts. The potential antimicrobial activity of alcohol-free red and white wine extracts against pathogenic strains of Staphylococcus aureus, Escherichia coli and Candida albicans was studied using the agar well diffusion method. Total phenolic content of wine extracts was determined by the Folin-Ciocalteu method, while their phenolic composition was specified by high performance liquid chromatography and diode array detector (HPLC-DAD). The antimicrobial activity of the tested extracts was related to their total phenolic content. Antimicrobial activity of the tested wine extracts was more effective against S. aureus and less effective against E. coli and C. albicans. Also, C. albicans was resistant to more wine extracts than the two bacterial species studied. The antimicrobial activity and the phenolic composition of the tested white and red wine extracts indicate that some phenolic acids have the potential to inhibit growth of certain pathogens such as S. aureus, E. coli and C. albicans strains