Cross-flow microfiltration applied to oenology: A review

Abstract

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.

Impact of winemaking practices on the concentration and composition of tannins in red wine

“…Filtering red wines prior to bottling is considered essential by many winemakers for maintaining clarity and stability in the finished wine (El Rayess et al 2011) as well as removing residual fining agents (Deckwart et al 2014). Wines are generally first treated with more coarse filtration membranes such as pad filtration with hydrophilic polyvinylidene fluoride (Bohanan et al 2012) or cross-flow filtration (El Rayess et al 2012a,b) and can then be filtered through a series of membranes with decreasing pore size (Ulbricht et al 2009).…”

Improvement on the concentrated grape juice physico-chemical characteristics by an enzymatic treatment and Membrane Separation Processes

“…After the firsts trials of cross-flow microfiltration with unsuitable results on the wine quality, the development of new filtration membrane along with a better understanding of the compounds involved in the membrane fouling have brought the selection of membrane suitable for wine fi ltration. In spite of progress made, some technological and economical barriers associated to the membrane fouling are still a limitation of the widespread application of this technique (El Rayess et al 2011). Unfortunately, even though macromolecules present in clarified fruit juice are much smaller than the pore size of typical microfi ltration membranes, they cause signifi cant fouling (Czekaj et al 2000).…”

Determination of Must and Wine Polysaccharides by Gas Chromatography-Mass Spectrometry (GC-MS) and Size-Exclusion Chromatography (SEC)

“…The ultrafiltration membranes covering a wide range of molecular weight cutoffs (MWCO) that overlap the molecular weight distribution of wine polysaccharides make this operation particularly appropriate to separate the wine polysaccharides. Applications of ultrafiltration membranes in enology have been described in the review of El Rayess et al (2011). However, dialysis is a method of choice in comparison to the ultrafiltration methods because there is no problem of membrane fouling which affects the operating costs and limits the application of the filtration membranes.…”