Trans-resveratrol (trans-3,5,4′-trihydroxystilbene) has been reported as contributing to the health promoting properties of wine. In this study wines made exclusively from native Portuguese varieties were assayed for the levels of trans-resveratrol. The method developed uses GC-FID and GC-MS determinations of TMS derivatives; dcrivatisation by hexamethyldisilazane following ether extraction of wines. Two currently used food anti-oxydants nordihydroguaiaretic acid (NDGA) and 2′,4′,5′-trihydroxybutyrophenone (THBP), were employed as internal standards, being extracted and derivatised in exactly the same way as the determined resveratrol. These internal standards permitted the verification of a good linearity and reproducibility for this determination, with a detection limit of 5 μg/l. A characteristic of this method is the enhanced discrimination between cis- and trans- isomers of resveratrol with the consequent possibility of the determination of cis-resveratrol. The levels of resveratrol from wines of different regions of Portugal was studied. There appeared to be considerable variation in the concentrations encountered in the various wines although generally red wines contained much higher levels than white wines. The use of glucosidase enzymes in winemaking led to an increase of 3- to 4-fold in the levels of resveratrol encountered in Vinho Verde wines. Differences were noted between the resveratrol levels of specific varietal wines from the Vinho Verde.
|Translated title of the contribution||Analysis of cis- and trans-resveratrol in Portuguese wines|
|Number of pages||7|
|Journal||Journal International des Sciences de la Vigne et du Vin|
|Publication status||Published - Jan 1996|
- GC analysis