Phenolic and Antioxidant Profile of Red Wines from Different Regions of Bulgaria Aged with Oak Chips

Abstract

The phenolic and antioxidant profiles of four red wines (Cabernet Franc, Syrah, Cabernet Sauvignon/Merlot blend, Carménère/Cabernet Sauvignon/Cabernet Franc/Merlot blend) from regions of northern and southern Bulgaria, aged in oak, were determined. Oak chips with different origins and degrees of toasting, as well as different times of contact with the wines, were applied. Different phenolic fractions were determined – the total phenolic compounds (TPC), flavonoid phenolic compounds (FPC), nonflavonoid phenolic compounds (NPC), the total phenolic index (TPI), and anthocyanins (ACNs). The spectral characteristics of the wines and their in vitro antioxidant activity were defined. The highest accumulation of phenols was found in the complex blend Carménère/Cabernet Sauvignon/Cabernet Franc/Merlot, harvest 2022, Harmanli, Southern Bulgaria. In direct relation to the phenolic profile, this wine also exhibited the highest radical scavenging capacity – with a potential to eliminate free DPPH radicals in vitro, reaching 91.43±0.04%. High antioxidant activity (83.14±0.01%) was also displayed by the wine of the Syrah variety from the region surrounding the town of Varna in Northern Bulgaria. The differences in the phenolic composition of the studied wines from the commercial network were the result of varietal characteristics, the type and amount of oak wood used, as well as the contact time. The conducted study enriched the scientific literature with valuable data regarding the phenolic and antioxidant profile, determining the biological potential of wines obtained in contact with oak wood, from grapes of vine varieties from different regions of Bulgaria.