White wine clarification by micro/ultrafiltration: effect of removed colloids in tartaric stability

A white wine was clarified by tangential microfiltration (MF) and ultrafilt ration (UF). The permeation experiments were carried out in a Dow Lab-unit M20 with a membrane area of 0.036 m(2). Two membranes were tested, one of M F with a pore size of 1.0 mum and another of UF with a molecular weight cut -off (MWCO) of 100 kDa. They are both made of a fluor polymer and supplied by DSS-Denmark. The operating conditions (pressure and circulation flow rat e) were optimised for both membranes. The MF and UF clarification experimen ts were performed at the same optimal conditions of 1 x 10(5) Pa transmembr ane pressure and 554 1 h(-1) circulation flowrate. The results were compare d in terms of permeate productivity, particle and polysaccharide removal. T he polysaccharides were precipitated from the raw wine, the UF permeate and the UF concentrate. Potassium hydrogen tartrate crystallisation induction times were measured at 0 degreesC using hydroalcoholic solutions with and w ithout these polysaccharides. MF and UF presented similar permeate producti vities and particle removal. The UF membrane proved to be easier to clean. Polysaccharide removal was low with both membranes: 10% for MF and 16% for UF. The polysaccharides retained by UF did not alter significantly the pota ssium hydrogen tartrate crystallisation induction times. These induction ti mes are similar for the model solution with the polysaccharides from the ra w wine and the UF clarified wine. (C) 2001 Elsevier Science B.V. All rights reserved.