Comparative study of crossflow microfiltration with conventional filtration of sherry wines (original) (raw)
Related papers
Cross-flow microfiltration of wine: Effect of colloids on critical fouling conditions
Journal of Membrane Science, 2011
Critical fouling conditions were studied during wine cross-flow microfiltration using a multichannel ceramic membrane (0.2 m). The aim was to determine critical operating conditions in order to limit fouling caused by wine colloids (tannins, pectin and mannoproteins) and enhance process performances. The method used is a square wave filtration based on the determination of the reversibility and irreversibility of fouling. Filtrations were performed with filtered red wine (FW) added with different concentrations of colloids. Considering FW, critical flux for irreversibility was beyond the studied range of pressure (≥1.4 × 10 −4 m/s). No clear critical flux could be determined for any of the tested molecules in the studied range of pressure. On the other hand, an upper limit of fluxes range has been identified (below which critical flux could be found). Irreversible fouling always takes place from the beginning of the filtrations and even at low pressures. For FW containing 0.2 g/l mannoprotein and 0.5 g/l pectin, a loss of average fluxes is observed beyond a given limit of transmembrane pressure. This fact was attributed to the compaction of a gel layer. Finally, a criterion (R if /R m ≤ 1) has been suggested to determine the so-called "threshold flux" below it, fouling remains acceptable.
Improvement of wine crossflow microfiltration by a new hybrid process
Journal of Food Engineering, 2007
A hybrid process comprising column adsorption and crossflow microfiltration was applied to reduce the unstable proteins of Pinot Noir wine and improve the permeate flux during wine microfiltration. The process was performed using a packed column with zirconium oxide and a ceramic membrane. Proteins and polyphenols were reduced by bentonite and activated carbon addition in order to evaluate their influence on permeate flux decline. The column adsorption process achieved a better protein stability and increased the permeate flux by 15-20%. The molecular weight range of 20-70 kDa could be related to unstable proteins or cause membrane fouling. The phenolic composition of wine was not affected by adsorption with zirconium oxide or the microfiltration process.
IMPACT OF THE PHYSICO-CHEMISTRY OF THE WINE ON MEMBRANE FILTRATION PERFORMANCE
During the process of wine making, operation of cross-flow microfiltration allows a one-step clarification and sterilization of wine, with lower waste compared to the conventional processes of clarification and sterilization. Indeed, these processes are sources of voluminous waste (earth, Kieselguhr, additives), when discharges are becoming more and more restricted by environmental and health rules. Nevertheless, cross-flow microfiltration of wine presents a major drawback: membrane fouling causes a significant decrease in the flow rates, due to excessive retention of some wine components which could lead ultimately to the alteration of the quality of wine. The aim of this work was to study the impact of some specific wine components (phenolic compounds and yeast extract), as well as some physico-chemical parameters (pH) in regard to membrane fouling. Studies were performed using one red wine and synthetic wines, using cellulose acetate membranes (0.2 μm) operated in the dead-end mode under 2 bar pressure. The simultaneous presence of the both species of phenolic compounds (anthocyanins and tannins) in the synthetic wine was shown to be the main cause of fouling, whereas the presence of one specie leads only to standard blocking type behavior. An important decrease in the flow rates was also observed when yeast extract was added to the liquid. This yeast extract was shown to contain 300 mg/g of proteins and to be free of mannoproteins. The influence of these proteins on fouling was demonstrated while pre-treating the synthetic wine with bentonite, which was able to adsorb proteins, and in this case, no fouling was observed. It was also shown that, when decreasing the pH, the flow rate was enhanced. For all experiments, a fouling index or cake specific resistance, according to the type of fouling, was calculated in order to be used as a reference to estimate the filterability of a given wine, according to its composition in some targeted molecules. Finally, the experiments of the actual red wine exhibited complete rapid fouling of the membrane, probably due to the presence of high concentration of phenolic compounds.
Chemical Engineering and Processing: Process Intensification, 2008
The aim of the present study was to investigate the respective impact of wine particles, i.e. Saccharomyces cerevisiae yeast and fines (lactic bacteria and colloidal aggregates), on the performances of cross-flow microfiltration under different permeate flux rate/wall shear stress conditions. Yeast were grown in a synthetic red wine and their surface properties characterized. The cells exhibited a hydrophilic character and were uncharged in the wine conditions. Yeast and fine behaviors were first investigated separately and then compared to that of their mixture. The shear induced diffusion theory well accounted for the whole evolution of the performances under the application of different hydrodynamic conditions. These performances were related to the deposit structure, which reversibility was experienced by alternating high and low TMP steps, and by SEM observations of the membrane surface. Yeast alone always formed reversible deposits, in relation with their surface properties. By contrast, fines formed a coherent and adherent cake above a given TMP. When yeast and fines were processed together, the TMP stepping mode strongly influenced the composition, final resistance and reversibility of the deposit.
Journal of Food Science, 1990
Two red wines, from the same cultivar, differing by polysaccharide content were filtered using cross-flow microfiltration with an alumina membrane, pore size 0.2 km. Filtration flow rates were different. The wine richest in polysaccharides (A) showed a typical external fouling profile with progressive stabilization, while wine B showed a permanent decrease in flux (external and internal fouling). Retention of polysaccharides negatively correlated with their hydrodynamic volume, overall losses being higher for wine B. Polysaccharides had a possible role in fouling related to their structures and molecular weight distribution in the two wines.
2000
Several main wine polysaccharides, isolated from a red wine and characterized in terms of composition and structural organization, have been microfiltered separately in a colloid-free synthetic wine to determine their respective incidence on the permeation fluxes of an hydrophilic organic microfiltration membrane. Most wine polysaccharides induced a significant decrease of the permeation flux density. The permeation flux decline were concentration-dependent
2015
In the present study, the clarification process appropriate operating values were identified by investigating the influence of temperature, transmembrane pressure (TMP) and feed flow rate on the crossflow microfiltration (CFM) process without enzymatic pre-treatment. Multichannel ceramic membrane with active filtration area 0.08494m 2 and nominal pore diameter of 2µm was used in lab-scale microfiltration unit to attain clarified apple juice. The experiments were performed using two modes (total recirculation mode and concentration mode). In total recirculation, the performance of flux with time was observed at feed flowrate 11 L.min -1 and at TMP of 3 and 4 bar respectively. A reduction in permeate flux was observed with time. The results showed in contrast to 3 bar run, the flux values at 4 bar was higher but the decay in flux of permeate with time at 4 bar was more rapid. In concentration mode, the flux behavior was almost the same as in total recycle mode but the values of flux ...