The influence of fining agents on the removal of some pesticides from white wine of Vitis vinifera L. cv. Emir.

The influences of fining agents (activated carbon, casein, kieselsol-gelatine, bentonite and polyvinylpolypyrrolidone) and their doses (low, middle, high) on the removal of six pesticides used in viticulture (vinclozolin, penconazole, α-endosulfan, imazalil, nuarimol and tetradifon) from white wine were investigated. The pesticides were added into white wine obtained from the Emir grape, and then the wine was clarified with the use of fining agents at low, middle and high doses. After the fining, extraction of pesticides from the wine was made by liquid-liquid extraction. Quantification and identification were performed by the multiresidual method using GC-MS and GC-ECD techniques. The effect of the fining agents on these pesticides ranged from little to large. Of the fining agents, activated carbon showed the largest effect on the removal of pesticides. The pesticide removal efficiencies of the fining agents were in the following order: activated carbon, casein, bentonite and kieselsol-gelatine. Polyvinylpolypyrrolidone (PVPP) had the least effect on the removal of pesticides. A linear relation was not found between fining agent doses and the amount of removed pesticides. α-Endosulfan, penconazole, imazalil and tetradifon were removed by the fining agents at the highest levels. Vinclozolin and nuarimol were the pesticides least affected, except activated carbon and casein.

Influence of Saccharomyces cerevisiae strains on fermentation and flavor compounds of white wines made from cv. Emir grown in Central Anatolia, Turkey.

The effect of inoculation with selected Saccharomyces cerevisiae strains was studied on fermentation and flavor compounds of wines made from Vitis vinifera L. cv. Emir grown in Central Anatolia, Turkey. Flavor compounds were analysed and identified by GC-FID and GC-MS, respectively. The total concentrations of flavor compounds did not increase with the addition of indigenous and commercial wine yeasts, but differences were noted in individual volatile compounds. Cluster and factor analyses of flavor compounds also showed that wines produced were different depending on the wine strain used. Wines were completely fermented to less than 1.4 g/l residual sugar. Yeasts other than S. cerevisiae survived longer than previously reported. Inoculation with selected strains increased the ethanol level.