| Popis: |
The organic acid content in red wine is very important due to its impact on wine aroma and it differs between wine varieties. Most common organic acids in red wine are tartaric, acetic, lactic or succinic acid. Their concentrations depend on wine production and storage conditions. Wine production procedures can include membrane filtration of wine, such as reverse osmosis (RO), that is used for wine concentration and chemical composition correction. The aim of this study was to investigate the influence of different pressures (2.5, 3.5, 4.5 and 5.5 MPa) and temperature regimes (with and without cooling) during reverse osmosis process on organic acid content in conventional and ecological Cabernet Sauvignon red wine concentrates. The results showed that initial concentrations of all acids decreased after RO process, but the retention of organic acids was higher if higher pressure and cooling was applied, especially at 5.5 MPa with cooling. However, the pressure of 2.5 MPa with cooling was also favourable for organic acids retention in conventional wine concentrate. Higher retention of tartaric and succinic acid was achieved in ecological wine concentrates, and higher retention of lactic acid was achieved in conventional wine concentrates at same processing parameters. The retention of acetic acid was similar in both wine concentrates, and its initial concentration decreased for more than 50%. The PCA analysis showed visible changes in organic acid profile of both wine, with differences between concentrates obtained at different operating conditions. |
