The application of an improved method for trans-resveratrol to determine the origin of Greek red wines

A rapid and sensitive method has been developed for the determination of trans-resveratrol in wine. This method consists of a solid phase extraction step followed by a rapid HPLC quantification step (30 min). The improvement of this method consists of the washing step of the solid phase extraction method carried out at pH 8.0 (12% ethanol in a phosphate buffer solution), thus permitting a more efficient removal of the interfering phenolic compounds in conjunction with the required low volume of tested sample. Trans-resveratrol content was determined for 29 red Greek wines of appellation of origin. The concentrations found varied between 0.550 and 2.534 mg/l. The wines produced by grape varieties grown in the Greek islands (Rhodes, Crete and Paros) were richer in trans-resveratrol. The grape variety Mandilaria, in particular, was the Greek variety with the highest trans-resveratrol content.