Antimicrobial properties, antioxidant activity and phenolic content of grape vinegars

A research on the total antioxidant capacity, total phenolic content and antimicrobial properties against Staphylococcus aureus, Escherichia coli and Candida albicans of grape vinegars was conducted. The research material consisted of vinegars made from different wine grape varieties grown in Poland. The study used white grape varieties: Solaris, Johanniter and Souvignier gris, as well as red varieties: Prior and Cabernet cortis. For each variety, two variants were prepared: with and without the addition of sugar in the fermentation process. The total antioxidant capacity and total phenolic content were determined by spectrophotometry. The minimum inhibitory concentration of the vinegars was determined using the microdilution method. The highest antimicrobial activity against all microorganisms was observed in the vinegar made from Solaris grapes with added sugar. The highest polyphenol content was observed in the vinegar made from the Prior grape variety with added sugar (143.77±14.74 mg of gallic acid /1 liter of liquid), and the highest total antioxidant capacity – in Johanniter with added sugar (203.67±35.73 mg Trolox Equivalent/1 liter of liquid). The vinegars examined in this study differed, depending on grape variety, in terms of antimicrobial properties, antioxidant capacity and total phenolic content. These differences were strongly associated with the grape variety used to vinegar preparation. Sugar addition caused an significant differences in the antioxidant capacity of vinegar samples.