Assessment of residual immunoreactivity in red or white wines clarified with pea or lupin extracts

Vegetable proteins could be a suitable alternative to animal proteins in the clarification of wine, but their residues could represent a risk for subjects with food allergy or intolerance. The aim of this study was to investigate the presence of specific immunoreactivity in red and white wines treated, as must or wine, with vegetable proteins in the clarification process. The proteins considered were prepared from lupins and peas, which are not included among the allergens listed in annex Illbis of Directive 2003/89/EC. The presence of residual immunoreactivity to specific rabbit anti-lupin and anti-pea polyclonal antibodies in treated wines was assessed by electrophoresis (SDS-PAGE) and immunoblotting. Residual protein was not detectable in red wines clarified with lupin, pea or a mixture of pea and lupin proteins or in white wines clarified with pea proteins. A small number of musts treated with lupin or pea proteins and white wines treated with lupin proteins yielded equivocal results, probably because of the presence of interfering material (e.g., sugar-rich proteins from grape and yeast). The use of bentonite as a secondary clarifying agent is therefore recommended since its combination with vegetable proteins is particularly effective in removing overall protein immunoreactivity.