P10
Selection of Saccharomyces
cerevisiae
strains with high ability to
adsorb ochratoxin A during fermentation
Giuseppe Blaiotta'', Valentina Coppola", Alberto Ritieni2, Andrea Pulvirenti" and
Andrea Caridl"
1 Scienze e Tecnologie Agro-Forestali e Ambientali, "Mediterranea" University of Reggio Calabria, Via Feo di Vito, Reggio Calabria 1-89122, ITALY, Phone: +39 0965 332642, FAX: +390965817794, e-rnail: acaridi@unircit,
Web: h!!P)/www.distafa.unirc.itldetl sezjpne.php?sect=8 2"Federico
ll
"
University of Napoli3 Modena and Reggio Emilia University
Ochratoxin A (OTA) exerts several toxic effects, mainly involving kidney and liver. Its
occurrence inwines, mainly in the red ones, has been widely reported (Zimmerli and
Dick, 1996). Recent studies prove the possibility to decontaminate grape musts with
selected yeasts able to remove OTA during winemaking (Bejaoui et al., 2004; Caridi
et al., 2006); this ability seems related tothe adsorption on the outermost layer ofthe
yeast celi wall and has been associated to the parietal mannoproteins, whose
content in
S. cerevisiae
depends on the specific yeast strain (Caridi, 2006). In thisstudy, 120 strains of
S
.
c
erevis
i
ae
coming from three Italian collections [Portici(Naples), Reggio Calabria and Reggio Emilia] previously characterized for their
physiological, technologieal and genetic features were tested invitro for OTA removal
capacity insynthetic rnust. Pre-cultures were prepared inYPD at28'C for 48 h. Tests
were performed intriplicate on 10 mi of synthetie must artificially contaminated wilh 5
ppb of OT A. After inoculums with 0.2 mi of YPD pre-culture, tubes were incubated at
25°C for 21 days. Residual OTA in wines was determined by HPLC as already
deseribed by Caridi et al. (2006), analyzing three aliquots of each tesi tube. In a
global view of results oblained itseams that S.
cerevisiae
strains are able to removeabout 45% of OTA during fermentalion (the mean value of the 120 wines was
45.75%
±
6.29). By contrast, analyzing in detail the results it is evident a highvariability: some strains were able to remove less Ihan 30% of OTA, others reached
removal levels of 55-60%. The occurrence of strains showing an OTA removal major
than 55%, and with a low standard deviation, were very low: a}two strains out 38 of the Portici colleclion (% of OTA removal: 58.83
±
1.12 and 57.13±
4.42, respectively); b) one strain out 18 of the Reggio Emilia colleclion (% of OTA removal:61.08
±
1.09); c) three strain out 64 of the Reggio Calabria colleetion (% of OTAremoval: 57.96
±
2.68, 57.35±
1.99, and 57.19±
3.88, respectively). ReferencesCaridi et al. (2006). Enzyme and Microbial Technology 40, 122-126. Caridi (2006).
Antonie van Leeuwenhoek 89, 417-422. Bejaoui et al. (2004). Journal of Applied
Microbiology 97, 1038-1044. Zimmerli and Dick (1996). Food Additives and
Contaminants 13, 655-68. This work was supported by PRIN 2007 "Wine strain
improvement strategies to enhance red wine safety based on parietal adsorption activity".
