Antimicrobial properties, antioxidant activity and phenolic content of grape vinegars

Justyna Antoniewicz,Wojciech Żwierełło,Katarzyna Janda,Karolina Jakubczyk,Marta Skórka- Majewicz,Paweł Kwiatkowski,Joanna Kochman

doi:10.3390/ecmc2020-07294

Abstract

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.

Highlights

The common grape vine (Vitis vinifera L.) is a fruit crop grown in many regions of the world, widely used in the food industry
The aim of the study was to determine the antioxidant capacity, total phenolic content and antimicrobial properties against E. coli, S. aureus and C. albicans of grape vinegars made from different varieties of the common grape vine (Vitis vinifera L.)
A change of colour from blue to pink after 3-hour incubation with resazurin at 37°C indicated the presence of bacteria/yeast

Summary

Introduction

The common grape vine (Vitis vinifera L.) is a fruit crop grown in many regions of the world, widely used in the food industry. They are most commonly eaten fresh, dried as a raisins, and can be processed into juice, wine, and vinegar. Fermentable sugars are converted to ethanol mainly by the yeasts. The most common substrates used for vinegar production are products with a high sugar content, but it can be made from alcohols, including wine. Fruit vinegars, including wine vinegars, contain many compounds with antioxidant properties, which may originate from the source material (i.e. fruit) as well as arise during the acetic fermentation process. The phenolic compounds found in vinegar increase its antioxidant capacity, and affect its colour and astringency

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Methods

Conclusion