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In this work reverse osmosis technology was used for removing alcohol from beer. The process was carried out in a diafiltration mode and it was possible to obtain a final beer with low ethanol content (less than 0.5% v/v). Several cellulose acetate and polyamide membranes were tested with transmembranar pressures ranging from 20 to 40 bar. Temperature and feed flowrate varied from 5 to 208C and from 2 to 7 l . min 21 , respectively. It was observed that permeate flux and alcohols rejection increase with the feed pressure, whereas esters rejection decreases with pressure. Permeate flux increases with temperature, while rejections decrease with it. Concentration polarization occurs at low feed flowrates.

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The aim of this study was to develop a rapid methodology for the analysis of α-tocopherol in vegetable oils as an alternative to the high-performance liquid chromatography (HPLC) methods: Fourier transform infrared (FT-IR) methodology. Thirteen vegetable oils (corn, peanut, soybean, sunflower and mixtures) commercially obtained were analysed by reverse-phase HPLC with fluorescence detection (FD) in order to obtain standard values for α-tocopherol. Validation tests were performed concerning the HPLC method. The HPLC method is valid for α-tocopherol analysis in the 1-90 mg/L linear range.Method repeatability was 3.6%, and accuracy results were within 70-95%. FT-IR spectra of the vegetable oils were acquired in the attenuated total reflection mode (45°and 60°crystals of ZnSe). To predict the α-tocopherol content in samples, calibration models were designed, and the partial least squares method was used to analyse data from FT-IR spectral region at 1,472-1,078 cm −1 . Results obtained showed that the calibration model implemented with a 45°c rystal is more suitable for the proposed analysis. Five extra samples of vegetable oils were analysed by HPLC/FD and by FT-IR. Using the calibration model implemented for FT-IR (45°crystal), the α-tocopherol content in samples was determined. The results obtained by HPLC/FD and FT-IR were compared, and there were no significant differences among them. Results showed that FT-IR can be used as an alternative method for rapid screening of α-tocopherol in vegetable oils without sample pre-treatment.

A mathematical model of fractionated condensation is proposed for predicting the recovery and fractionation of target aromas from red wine fermentation headspaces in order to remove off-flavours. The applicability of the model is assessed for two different alternative processes: fractionated condensation and vapour permeation–fractionated condensation. The aromas of the headspace of red wine fermentation are commonly lost through the fermenter venting system and are enhanced by the stripping effect of the produced CO2. To mimic the operating conditions during the red wine fermentation, all experiments were performed at 30 °C with a red wine model solution containing relevant red wine aromas, the cosolvent ethanol at representative concentrations, and CO2. Both studied processes allow for a good recovery of esters in the 2nd condenser, with over 80% of ethyl acetate and isoamyl acetate recovery when using vapour permeation–fractionated condensation and a recovery of 84–96% of all esters when using fractionated condensation. However, only the integrated process of vapour permeation–fractionated condensation achieves a significant decrease in the amount of ethyl phenols (off-flavours compounds) in the 1st condenser, above 50%, as expected due to the use of an organophilic membrane. The developed model was validated experimentally for the integrated process, proving to be a highly valuable tool for the prediction of aroma fractionation, aiming at the removal of off-flavours.