An Alternative Method for the Determination of Some of the Antioxidant Phenolics in Varietal Turkish Red Wines

The concentration of eight biologically important phenolic compounds (β-coumaric acid, gallic acid, ferulic acid, caffeic acid, trans-resveratrol, quercetin, (+)- catechin and (−)- epicatechin) of red wines produced on a pilot plant scale were determined using gas chromatography with mass spectrometric detection in the selective ion monitoring mode (GC/MS-SIM). The procedure involved an easy fractionation and liquid-liquid extraction method. For derivatization, BSA [N,O-bis-trimethylsilyl aceta-mide] / TMCS was used. The results showed that the p-coumaric acid, gallic acid, ferulic acid, caffeic acid, trans-resveratrol, quercetin, (+)- catechin and (−)-epicatechin levels in the wine samples ranged between 2.05 and 4.21 mg/L; 21.78 and 60.83 mg/L; 0.33 and 0.82 mg/L; 1.50 and 4.06 mg/L; 0.96 and 3.93 mg/L; 2.66 and 3.14 mg/L; 8.72 and 11.30 mg/L; 5.50 and 9.58 mg/L, respectively. Although the quercetin and trans-resveratrol levels of Turkish red wines were similar to previously reported values, (+)- catechin and (−)- epicatechin levels were lower than the values of red wines originating from other countries.