Characterization of the proteins from grapes and wines by immunological methods

In a previous work, we produced highly specific, polyclonal antibodies agai nst the total proteins or individual polypeptides of a Portuguese wine prep ared from the single grape variety Assario. Using immunological methods, im munoblotting in particular, we have applied these antibodies to analyze the origin of the wine proteins and to detect the presence of identical or sim ilar proteins in distinct wines or in wines prepared from different grape v arieties, The results obtained indicate that the different Assario wine pro teins show some degree of structural similarity. Furthermore, when the tota l protein composition of grape skin, pulp, seed, stem, leaf and yeast was a nalyzed, the Assario proteins were found to originate entirely from the pul p. However, important changes were noted to occur in the pulp proteins duri ng vinification. On the other hand, grapes from different, white or red var ieties, were found to contain a set of polypeptides identical to those pres ent in the Assario grapes. In addition, wines appear to contain a structura lly identical or very similar set of polypeptides, regardless of the variet y, year or region of the grapes utilized in their production.