Fac-simile Scheda Linee di Ricerca - Federalimentare

Parole chiave- vino- uva- proteine- polisaccaridi- stabilitàDati pubblicati inerenti il tema di ricerca:1. Curioni A., Vincenzi S., Flamini R. 2008: In “Hyphenated Techniques in Grape and WineChemistry”, Chapter VIII “Proteins and Peptides in Grape & Wine”. R. Flamini Ed., John Wiley& Sons, Chichester, UK.2. Lomolino G., Curioni A. 2007 Protein faze formation in white wines: effect of Saccharomycescerevisiae cell wall components prepared with different procedures. Journal of Agriculturaland Food Chemistry, 55, 8737–8744.Cell wall material was extracted by five different methods from an oenological strain of Saccharomyces cerevisiae.Enzyme preparations containing beta-glucanase activity (Zymolyase, Glucanex, and Finizym 250L) alloweda better extraction yield compared to that of dithiothreitol (DTT) and EDTA. The yeast extracts were onlysoluble in part in wine. The wine-soluble fraction (WSF) of the five extracts, differing in both protein and sugarcontents, when added in increasing amounts to white wine differently affected protein haze formation, as determinedby the heat test, giving dose/response curves of different shapes. The curves obtained with the WSF derivedfrom DDT and Zymolyase extracts showed a plateau value corresponding to 90% and 80% of wine hazereduction, respectively. In contrast, additino of the WSF derived from the other extracts resulted in increasedturbidity with respect to the original wine. The mannoproteins (MP), isolated from each yeast extract by Concanavalin-Achromatography, gave dose/response curves showing shapes more similar among them than those obtainedwith the whole WSFs. The best wine stabilization was obtained with the MP of the DTT and Zymolyaseextracts. The supernatants obtained after heating the MP of the different extracts were also tested. The stabilizingeffect of the heat-stable MP (HSMP) was always larger than that of the corresponding total (un-heated) MP. TheHSMP obtained starting from the DTT and Zymolyase extracts showed the best haze-protecting effect, whichwas, however, lower than that obtained with their corresponding WSF. This result suggests that wine protein stabilizationby compounds of the yeast cell wall could be related, in addition to the action of the MP, also to thepresence of other substances of different nature.3. Lomolino G., Lante A., Rizzi C., Spettoli P., Curioni A. 2005 Comparison of esterase patternsof three yeast strains as obtained with different synthetic substrates. Journal of the Institute ofBrewing 111, 234-236.The visualisation of wine yeast esterase (carboxylesterase EC 3.1.1.1) activity was performed by using differentchromogenic and fluorescent substrates. The zymograms revealed the presence of several isoforms in yeast extracts,differing in sub-cellular location, substrate specificity and electrophoretic mobility, indicating a high levelof polymorphism.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it306