Detection with flash gas chromatography electronic nose of the general influences of glutathione, ascorbic acid, tannin and carbon dioxide treatments on the volatile profiles of white wines of feteasca regala

Abstract

The present work aimed to determine some of the influences of the treatments with glutathione (GSH), ascorbic acid (AA), catechinic tannin (T) and carbon dioxide (CO2 ) during winemaking or bottling on the volatile profiles of white wines of Feteasca Regala. The study is based on the use of a flash gas chromatography electronic nose, which is able to discriminate various clusters of wine samples prepared with various combinations of antioxidants. The treatments that induce enough differences in the volatile profiles of the wine that the electronic nose is able to discriminate are likely to be discriminated also by the consumers. When the electronic nose does not discriminate the clusters of samples with certain treatments it is very likely that those treatments are not sufficient to induce a practically important difference in the aromatic profile of wines. The main detectable influences of the antioxidant treatments are presented and discussed. The treatment of musts with AA (50 mg/l) clearly influences the volatile profile of the wines, reducing their aromatic complexity. The treatment during bottling with catechinic tannin (20 mg/l) does not seem to have an important influence of the profile of the wines produced with the addition of AA and or GSH. The addition of carbon dioxide during bottling does not show much influence one year after bottling, but it shows that in the samples most prone to oxidation, a difference is present. The CO2 treated wines belonging to the cluster of wines treated with 40 mg/l GSH and 50 mg/l AA have distinct profiles, different from those not protected and closer to the clusters of the less oxidised wines. The treatment of musts with GSH shows clear influences at the dose of 40 mg/l, but for the lower dose of 20 mg/l GSH in Feteasca regala wines it is difficult to identify differences compared to the wines included in the cluster of samples not treated with GSH. This finding is particularly relevant as the dose of 20 mg/l GSH is the maximum allowed at present to be added in must and wines.