Phenolic compounds present in natural haze protein of Sauvignon white wine

Protein haze in white wines remains a problem for wineries. In addition to protein composition, many other factors have been identified that can participate in and even trigger the appearance of hazes. Phenolic compounds may be one of the non-protein factors involved in protein haze formation. The aim of this study was to identify and quantify the polyphenols present in the natural precipitate of a Sauvignon wine. The identification and quantification of polyphenols present in wine before and after natural precipitation and also in a natural precipitate were carried out by GC/MS and HPLC/ESI-TOF. The natural precipitate was also hydrolyzed in an acidic medium (Bate-Smith reaction). The results indicate that several phenolic compounds were present in the protein haze (tyrosol, trans-p-coumaric, trans-caffeic, vanillic, protocatechuic, syringic, gallic, ferulic, shikimic acids, (+)-catechin, ethyl coumaric acid ester and quercetin). Moreover, the detection of cyanidin after acid hydrolysis indicates the presence of procyanidins.